[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

The following issue has been set as RELATED TO issue 051. 
== 
https://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: Applied
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  Approved 
Final Accepted Text:https://austingroupbugs.net/view.php?id=1150#c4184 
Resolution: Accepted As Marked
Fixed in Version:   
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2019-11-07 09:21 UTC
== 
Summary:exit status of command substitution not properly
specified
==
Relationships   ID  Summary
--
related to  0001309 Clarity needed for initial value of $? ...
related to  051 sh exit status not clear for built-in t...
== 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
2018-12-11 16:33 chet_ramey Note Added: 0004181  
2018-12-13 16:24 geoffclare Note Added: 0004184  
2018-12-13 16:25 geoffclare Interp Status => Pending 
2018-12-13 16:25 geoffclare Final Accepted Text   =>
https://austingroupbugs.net/view.php?id=1150#c4184
2018-12-13 16:25 geoffclare Status   New => Interpretation
Required
2018-12-13 16:25 

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

The following issue has been set as RELATED TO issue 0001309. 
== 
https://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: Applied
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  Approved 
Final Accepted Text:https://austingroupbugs.net/view.php?id=1150#c4184 
Resolution: Accepted As Marked
Fixed in Version:   
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2019-11-07 09:21 UTC
== 
Summary:exit status of command substitution not properly
specified
==
Relationships   ID  Summary
--
related to  0001309 Clarity needed for initial value of $? ...
== 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
2018-12-11 16:33 chet_ramey Note Added: 0004181  
2018-12-13 16:24 geoffclare Note Added: 0004184  
2018-12-13 16:25 geoffclare Interp Status => Pending 
2018-12-13 16:25 geoffclare Final Accepted Text   =>
https://austingroupbugs.net/view.php?id=1150#c4184
2018-12-13 16:25 geoffclare Status   New => Interpretation
Required
2018-12-13 16:25 geoffclare Resolution   Open => Accepted As
Marked

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

The following issue has a resolution that has been APPLIED. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: Applied
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  Approved 
Final Accepted Text:http://austingroupbugs.net/view.php?id=1150#c4184 
Resolution: Accepted As Marked
Fixed in Version:   
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2019-11-07 09:21 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
2018-12-11 16:33 chet_ramey Note Added: 0004181  
2018-12-13 16:24 geoffclare Note Added: 0004184  
2018-12-13 16:25 geoffclare Interp Status => Pending 
2018-12-13 16:25 geoffclare Final Accepted Text   =>
http://austingroupbugs.net/view.php?id=1150#c4184
2018-12-13 16:25 geoffclare Status   New => Interpretation
Required
2018-12-13 16:25 geoffclare Resolution   Open => Accepted As
Marked
2018-12-13 16:26 geoffclare Tag Attached: tc3-2008   
2019-01-08 14:40 agadminInterp StatusPending => Proposed 
2019-01-08 14:40 agadminNote Added: 0004199  
2019-02-11 17:28 agadmin  

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

The following issue has been UPDATED. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: Interpretation Required
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  Approved 
Final Accepted Text:http://austingroupbugs.net/view.php?id=1150#c4184 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2019-02-11 17:28 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004248) agadmin (administrator) - 2019-02-11 17:28
 http://austingroupbugs.net/view.php?id=1150#c4248 
-- 
Interpretation approved: 11 Feb 2019 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
2018-12-11 16:33 chet_ramey Note Added: 0004181  
2018-12-13 16:24 geoffclare Note Added: 0004184  
2018-12-13 16:25 geoffclare Interp Status => Pending 
2018-12-13 16:25 geoffclare Final Accepted Text   =>
http://austingroupbugs.net/view.php?id=1150#c4184
2018-12-13 16:25 geoffclare Status   New => Interpretation
Required
2018-12-13 16:25 geoffclare Resolution   Open => Accepted As
Marked
2018-12-13 16:26 geoffclare Tag Attached: 

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

The following issue NEEDS AN INTERPRETATION. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: Interpretation Required
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  Pending 
Final Accepted Text:http://austingroupbugs.net/view.php?id=1150#c4184 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-13 16:25 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
2018-12-11 16:33 chet_ramey Note Added: 0004181  
2018-12-13 16:24 geoffclare Note Added: 0004184  
2018-12-13 16:25 geoffclare Interp Status => Pending 
2018-12-13 16:25 geoffclare Final Accepted Text   =>
http://austingroupbugs.net/view.php?id=1150#c4184
2018-12-13 16:25 geoffclare Status   New => Interpretation
Required
2018-12-13 16:25 geoffclare Resolution   Open => Accepted As
Marked
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-13 16:24 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004184) geoffclare (manager) - 2018-12-13 16:24
 http://austingroupbugs.net/view.php?id=1150#c4184 
-- 
Interpretation response

The standard is unclear on this issue, and no conformance distinction can
be made between alternative implementations based on this. This is being
referred to the sponsor.

Rationale:
-
None.

Notes to the Editor (not part of this interpretation):
---
On page 2350 line 74877 section 2.5.2, change:Expands to the
decimal exit status of the most recent pipeline (see [xref to
2.9.2]).to:Expands to the decimal exit status of
the most recent pipeline (see [xref to 2.9.2]) that was not within a
command substitution (see [xref to 2.6.3]).
Note: In var=$(some_command); echo $? the output is the exit
status of some_command but this is because its exit status becomes
the exit status of the assignment command var=$(some_command) (see
[xref to 2.9.1]) and this assignment command is the most recent
pipeline.
On page 2366 line 75543 section 2.9.1, change:with the exit
status of the last command substitution
performedto:with the exit status of the command
substitution whose exit status was the last to be obtained
On page 2410 line 77132 section 2.14 set, change:The failure of
any individual command in a multi-command pipeline shall not cause the
shell to exit. Only the failure of the pipeline itself shall be
considered.to:The failure of any individual
command in a multi-command pipeline, or of any subshell environments in
which command substitution was performed during word expansion, shall not
cause the shell to exit. Only the failure of the pipeline itself shall be
considered.
On page 2410 line 77145 section 2.14 set, add:In
set -e; echo $(false; echo one) two
the false command causes the subshell in which the command
substitution is performed to exit without executing echo one; the
exit status of the subshell is ignored and the shell then executes the
word-expanded command echo two. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kre   

Re: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Geoff Clare]

Robert Elz  wrote, on 12 Dec 2018:
>
> Date:Tue, 11 Dec 2018 16:33:39 +
> From:Austin Group Bug Tracker 
> Message-ID:  <83857fbeb34fcb776e74f9e733705...@austingroupbugs.net>
> 
> 
>   | But they're not performed by the same execution environment.
>   |
>   | From the perspective of the assignment statement, there is only one 
> command
>   | substitution. Maybe that's the assumption that needs to be cleaned up. 
> 
> Perhaps.   Currently the spec is juist "the last command substitution 
> performed" - not wrt anything in particular's perspective.   The inner
> ones have to be performed too.
> 
> Whatever is fixed, something needs to be.

How about changing:

with the exit status of the last command substitution performed

to:

with the exit status of the command substitution whose exit status
was the last to be obtained

-- 
Geoff Clare 
The Open Group, Apex Plaza, Forbury Road, Reading, RG1 1AX, England

Re: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Robert Elz]

Date:Tue, 11 Dec 2018 16:33:39 +
From:Austin Group Bug Tracker 
Message-ID:  <83857fbeb34fcb776e74f9e733705...@austingroupbugs.net>


  | But they're not performed by the same execution environment.
  |
  | From the perspective of the assignment statement, there is only one command
  | substitution. Maybe that's the assumption that needs to be cleaned up. 

Perhaps.   Currently the spec is juist "the last command substitution 
performed" - not wrt anything in particular's perspective.   The inner
ones have to be performed too.

Whatever is fixed, something needs to be.

kre

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-11 16:33 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004181) chet_ramey (reporter) - 2018-12-11 16:33
 http://austingroupbugs.net/view.php?id=1150#c4181 
-- 
Re: 4180

But they're not performed by the same execution environment.

>From the perspective of the assignment statement, there is only one command
substitution. Maybe that's the assumption that needs to be cleaned up. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
2018-12-11 16:33 chet_ramey Note Added: 0004181  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-11 16:25 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004180) kre (reporter) - 2018-12-11 16:25
 http://austingroupbugs.net/view.php?id=1150#c4180 
-- 
Re 4179

In a=$(cmd $(exit 1) )  the outer command substitution has to start
first (or the inner one is never expanded) yet the outer one cannot
finish until the inner one is finished.

It may seem obvious that that the inner one cannot provide the exit status
of the outer var-assign, but there's nothing that actually says that.
All we have is that the last one performed is the one that provides the
status.

What the answer should be I am taking no position on at all, just that all
of this needs to be cleaned up, one way or another. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
2018-12-11 16:25 kreNote Added: 0004180  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-11 15:38 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004179) chet_ramey (reporter) - 2018-12-11 15:38
 http://austingroupbugs.net/view.php?id=1150#c4179 
-- 
Re: 4176

Given that command substitutions are performed "beginning to end," as are
all the word expansions, and they are intended to be synchronous, isn't the
last one started the last one finished?

Maybe the thing to do is to make the synchronous nature of command
substitution explicit. I couldn't find anything that says the shell waits
for the subshell environment to finish before moving onto the next
expansion, but everyone seems to do it that way. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
2018-12-11 15:38 chet_ramey Note Added: 0004179  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-11 14:52 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004178) chet_ramey (reporter) - 2018-12-11 14:52
 http://austingroupbugs.net/view.php?id=1150#c4178 
-- 
Re: 4177

POSIX already uses "beginning to end" where that makes a difference: the
order in which the shell expands words, and the order of processing words
in a simple command, to name two.

Whether or not the last element of a pipeline should run in the parent
shell context is already covered (and made optional) in 2.12.

Changing the behavior of `echo foo | read var' to run the last element in
the parent's context in a shell where job control is enabled and you have
to support suspending the processes is a nasty job, and I, for one, am not
interested at this time. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
2018-12-11 12:50 joerg  Note Edited: 0004177 
2018-12-11 14:52 chet_ramey Note Added: 0004178  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-11 12:49 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004177) joerg (reporter) - 2018-12-11 12:49
 http://austingroupbugs.net/view.php?id=1150#c4177 
-- 
While newer shells seem to agree that

  a=1 b=2 

is evaluated from left to right, note that the original Bourne Shell
does it from right to left and I am not aware of a text in POSIX that
requires a specific order.


a=$( $(exit 1) $(exit 3) )

behaves different from

a=$(ls $(exit 1) $(exit 3) )

and in this area, most shells (except zsh) seem to be aligned.

There is a nasty list of things that I believe should be defined in
POSIX and that is e.g.

The order of evaluation for

   a=1 b=2

whether the command

   echo foo | read var

should put foo in $var

and similar things.

The problem is that changing the behavior for exit or shell -ce
should take less than a day if the maintainerknows his shell, but
changing the behavior for echo foo | read var may take more than a 
month. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
2018-12-11 10:09 kreNote Added: 0004176  
2018-12-11 12:49 joerg  Note Added: 0004177  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-12-11 10:09 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0004176) kre (reporter) - 2018-12-11 10:09
 http://austingroupbugs.net/view.php?id=1150#c4176 
-- 
There is one more issue that ought to be resolved with
all of this, as it is all related.

In XCU section 2.9.1, page 2366, lines 75541-3) we see:

  If there is no command name, but the command contained
  a command substitution, the command shall complete with
  the exit status of the last command substitution performed.

This is the one case where the use of the exit status
of a cmd sub is stated explicitly - but even this is
not really properly defined.

Which is "the last" command substitution performed ?
This turns on just what "performed" means for this,
I think.   And I do not know the answer in general.

It is easy in the simple cases:
a=$(cmd1) b=$(cmd2)
it is the exit status of cmd2, as those are eval'd
left to right.   Same in:
>$(echo file1; exit 1) 2>$(echo file2; exit 2)
it is 2, as those are also eval'd L to R.

Even in
a=$(cmd) >$(echo file; exit 17)
where it can be either the exit status of cmd, or 17,
as it depends upon which order the shell decides to
eval var-assigns and cmd-subs when there is no command
word (which can vary according to lines 75498-500), so
even though a user cannot rely upon which it will be,
the status that should be returned by any particular
shell is clear.

But what about a=$(cmd $(exit 3)) ?

Which command substitution is performed last?
Is it the one started last, or the one that
finished last?

In that cmd is run with no args, its stdout is
assigned to a, and the exit status is???

It seems obvious to say the exit status of cmd, as
that one finishes last, and one might say that the
command substitution has not been performed until it
has completed, but what if cmd is $(exit 1) so
what we have is ...

a=$( $(exit 1) $(exit 3) )

which one is now the command substitution that is
performed last?   Is it still "cmd" ?

Note here that we are talking about the exit status
of the command which is the empty command word with
the variable assignment to a, not the exit status of
the command substitution performed in order to discover
the value to be assigned - except if that one is the one
picked as the "last performed".

I have not tested what the various shells do with this
(not even the NetBSD shell) - I really do not care.
Nor does anyone else.  However that the standard should
be complete - and not leave things as "anyone's guess".

What the shells currently do with any of these now is,
I would submit, irrelevant - they can all be changed if
needed (nothing is going to break because of that as
no-one in any real script is insane enough to actually
use any of these constructs, and if there is one, they
deserve whatever misfortune lands upon them).   If they
were all the same that might be useful, but we know that
is not the case.

So, what should be done is to define this (all of this
in this bug report) in the way that makes most logical
sense, which also should be the way that is easiest
to fully specify. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kre 

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2018-03-09 22:55 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003936) stephane (reporter) - 2018-03-09 22:55
 http://austingroupbugs.net/view.php?id=1150#c3936 
-- 
Another case where we see diverging behaviours:

   for i in $(exit 4); do
 not run
   done
   echo "$?"

Or

   case $(exit 4) in (x) ;; esac
   echo "$?"

Most shells output 0, ksh93 outputs 4 (doesn't exit with errexit).

In

   case x in ($(exit 4));; esac; echo "$?"

zsh and ksh93 output 4. With errexit, zsh exits, but not ksh93 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
2017-06-17 08:31 kreNote Added: 0003782  
2018-03-09 22:55 stephane   Note Added: 0003936  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-17 08:31 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003782) kre (reporter) - 2017-06-17 08:31
 http://austingroupbugs.net/view.php?id=1150#c3782 
-- 
Re 3781...

It is actually quite explicit, re-read 2.9.1 (steps 1-4 in the prelude,
and
what immediately follows) and you will see it (should see it.)

The shell takes the (unexpanded) command line, removes any words that are
var-assigns (start with unquoted name= and precede any non-redirect word
which does not start that way) and any redirect words (contain an unquoted
redirect operator), then applies the expansion rules to all the words that
are left.  The result of this can have some words vanish (expand to
nothing)
and new words appear (file name expansion, field splitting).

Once that is complete we look at what resulted, if they are any words it
is some kind of command (function, built in, whatever), and is processed
that way (and its exit status comes from the command - which can include
the 126 and 127 exit codes from the shell attempting to execute the
command.)

If there were are no words remaining (either never were any, or they
all vanished) then the rules for processing commandless redirections and
variable expansions apply.  In this case (and as stated at least, only in
this case) does the exit status of the last executed command substitution
(when the redirects and var-assigns are expanded, or possibly from the
earlier
word expansions) get used to set $? (the exit status of the empty command.) 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-17 07:51 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003781) shware_systems (reporter) - 2017-06-17 07:51
 http://austingroupbugs.net/view.php?id=1150#c3781 
-- 
Re: 3779
I agree the intent is along those lines, but isn't explicit enough to rule
out the case presented. It's little different from 'a=echo; $a "Output
TexT";', which I'd expect to write to stdout. The substitution results get
evaluated as the command name that affects $?, whether arguments present or
not. An implementation might limit 127 to case where './echox "Text";' not
found on the path, for the simpler usage not involving command
substitution, to resolve the conflicting requirements. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
2017-06-16 16:45 joerg  Note Edited: 0003780 
2017-06-17 07:51 shware_systems Note Added: 0003781  
==

Re: order of assignments (Was: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified)

[Robert Elz]

OK, when I reread the line in question more carefully, I see that it
only applies in the case where there is a command word (which is not...)

I think left to right is now specified (in all cases) as earlier it
says...

the following expansions, assignments, and redirections shall all be
performed from the beginning of the command text to the end:

bit wrt assignments all it says is ...

Each variable assignment shall be expanded for tilde expansion,
parameter expansion, command substitution, arithmetic expansion,
and quote removal prior to assigning the value.

It does not say how much prior, nor how little, so I still believe it
is possible to expand all the variable assignments (left to right, or
beginning to end) prior to assigning the values, and then assign the
values, left to right.

On the other hand I cannot imagine actually implementing it that way.

But $? is different, it is typically defined to be set once for each
command - for a simple command with no command word (just assignments
and redirects) it is to be the last command substitution performed (not
any of the others.)   We cannot know which is last until all have been
performed (all expansions expanded, at least) so we should not be
assigning to $? until everything else has been done.

Whatever the result is, clearly more (or better) specification is needed.

kre

Re: order of assignments (Was: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified)

[Joerg Schilling]

Stephane CHAZELAS  wrote:

> The discussion (on austin group) I was remembering of was in
> April 2010, with "Assignment with command: export only, or sets
> variable, too?" as the subject.
>
> Followup on dash mailing list at
> http://comments.gmane.org/gmane.comp.shells.dash/265

Just the mentioned expected result was wrong as X was not unset while
executing Y=${X=b}

Jörg

-- 
 EMail:jo...@schily.net(home) Jörg Schilling D-13353 Berlin
joerg.schill...@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
 URL: http://cdrecord.org/private/ http://sf.net/projects/schilytools/files/'

Re: order of assignments (Was: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified)

[Robert Elz]

Date:Fri, 16 Jun 2017 17:32:44 +0100
From:Stephane CHAZELAS 
Message-ID:  <20170616163244.ga4...@chaz.gmail.com>

  | Is it really? 

The text that says it is still there.   Line 75508 in TC2

  | I do remember it was discussed some time ago and the outcome was
  | that $b should be x.

If there is a bug report and resolution somewhere, it clearly has
not yet been applied.

Note that while left->right or right->left might be one issue, I
always presumed that the main question here was whether all the
variable assignments were expanded in parallel, then assigned in
parallel (well, probably assigned one after the other, but after
all expansions for the new values for all of them had been made.)

that is, input is
a=x b=$a
word expand that
a=x b=a
execute (make the assignments).

kre

Re: order of assignments (Was: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified)

[Stephane CHAZELAS]

2017-06-16 18:38:42 +0200, Joerg Schilling:
[...]
> > I do remember it was discussed some time ago and the outcome was
> > that $b should be x. It was reported to "dash" (as a POSIX
> > conformance bug) and despite initial reticence, dash was changed
> > so as to perform assignments left to right (as anybody would
> > expect).
> 
> The historic Bourne Shell made a list of macro assignments be executed right 
> to 
> left which is against common sense.
> 
> I am not sure whether POSIX requires a specific order. I changed the 
> execution 
> order in bosh to be left to right long ago.
[...]

The discussion (on austin group) I was remembering of was in
April 2010, with "Assignment with command: export only, or sets
variable, too?" as the subject.

Followup on dash mailing list at
http://comments.gmane.org/gmane.comp.shells.dash/265

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 16:45 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003780) joerg (reporter) - 2017-06-16 16:45
 http://austingroupbugs.net/view.php?id=1150#c3780 
-- 
What gets assigned with

a=$(exit 4) b=$?

may depend on whether the macro expansion is done for all assignments
first or step by step and whether/where is a checkpoint to save the
exit code for $? expansion.

You are githt for a=$(exit 4) b=$?; echo $? 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
2017-06-16 16:43 kreNote Edited: 0003779 
2017-06-16 16:45 joerg  Note Added: 0003780  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 16:40 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003779) kre (reporter) - 2017-06-16 16:40
 http://austingroupbugs.net/view.php?id=1150#c3779 
-- 
Re 3777, no it can't be read that way - if there is a command word at all
then 2.9.1 does not apply, and the exit status is that that comes from
executing the command word - even if that was originally planned on being
an arg to a command which failed to be produced, and so ends up producing
a 127 exit code.   If there was no "argish1" in your example, then the
exit code would be 5. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
2017-06-16 16:35 kreNote Added: 0003778  
2017-06-16 16:40 kreNote Added: 0003779  
==

Re: order of assignments (Was: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified)

[Joerg Schilling]

Stephane CHAZELAS  wrote:

> 2017-06-16 16:19:27 +, Austin Group Bug Tracker:
> [...]
> > In
> > a=a; a=x b=$a
> > it is explicitly unspecified whether b=a or b=x at
> > the conclusion.  It would be astounding if there was
> > to be a stricter requirement for $?
> [...]
>
> Is it really? 
>
> I do remember it was discussed some time ago and the outcome was
> that $b should be x. It was reported to "dash" (as a POSIX
> conformance bug) and despite initial reticence, dash was changed
> so as to perform assignments left to right (as anybody would
> expect).

The historic Bourne Shell made a list of macro assignments be executed right to 
left which is against common sense.

I am not sure whether POSIX requires a specific order. I changed the execution 
order in bosh to be left to right long ago.

Jörg

-- 
 EMail:jo...@schily.net(home) Jörg Schilling D-13353 Berlin
joerg.schill...@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
 URL: http://cdrecord.org/private/ http://sf.net/projects/schilytools/files/'

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 16:33 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003777) shware_systems (reporter) - 2017-06-16 16:33
 http://austingroupbugs.net/view.php?id=1150#c3777 
-- 
Re:
"There is what is said in 2.9.1 about
a=$(command)
which uses the status of command as the status of the assignment, when
there is no command word, but that is the only case that is explicit."

This can be construed that assignments and redirections are not included,
and command as used there is only the words that are what should be the
command name and any arguments. Example:
a="" $(does-not-write-a-command-to-stdout-but-exits-5) argish1
would have the 5 as new value for $?.
If the command name does not name a function, built-in, or file on the
path, the result from the command substitution would override the 127
return of "command not found". I'm not saying this is the intent, just that
it can be read that way and lead to some of the differences discussed. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
2017-06-16 16:33 shware_systems Note Added: 0003777  
==

order of assignments (Was: [1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified)

[Stephane CHAZELAS]

2017-06-16 16:19:27 +, Austin Group Bug Tracker:
[...]
> In
> a=a; a=x b=$a
> it is explicitly unspecified whether b=a or b=x at
> the conclusion.  It would be astounding if there was
> to be a stricter requirement for $?
[...]

Is it really? 

I do remember it was discussed some time ago and the outcome was
that $b should be x. It was reported to "dash" (as a POSIX
conformance bug) and despite initial reticence, dash was changed
so as to perform assignments left to right (as anybody would
expect).

I'll try and dig up the discussion(s), though not today.

-- 
Stephane

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 16:19 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003776) kre (reporter) - 2017-06-16 16:19
 http://austingroupbugs.net/view.php?id=1150#c3776 
-- 
Re note 3773:

  | Not many people would object that
  | a=$(exit 4) b=$?
  | may (if not should) assign 4 to $b 

I would not object to may, but would to should.

In
a=a; a=x b=$a
it is explicitly unspecified whether b=a or b=x at
the conclusion.  It would be astounding if there was
to be a stricter requirement for $?

ash based shells (not just dash) only set $? after
this whole simple command has completed, then set
it to 4 (the result of the last cmdsub in a command
with no command word, as required.)

Exactly when $? is required to be updated is perhaps
something else that needs better specification, this
relates to the "checkpoints" that Joerg mentions in
note 3774.

I doubt much, if anything, will be broken, whatever
ends up being specified here, until the issue appeared
during an academic discussion on a related topic a day
or two ago, I had no idea that shells behaved differently.
If any scripts were being affected by that, I think we
would have heard about it before now. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
2017-06-16 16:19 kreNote Added: 0003776  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 16:05 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003775) stephane (reporter) - 2017-06-16 16:05
 http://austingroupbugs.net/view.php?id=1150#c3775 
-- 
Re: http://austingroupbugs.net/view.php?id=1150#c3774

Here, that's one case where it doesn't really matter. I agree 3 is the most
sensible outcome. Like in

$SHELL -c 'f() { (exit 3); a=$(exit 1) return; } ; f; echo $?'

(ksh93 returns 0 which clearly is a bug)

But that doesn't really matter because nobody is going to pass a cmdsubst
that expands to nothing to exit or return or call return with a preceding
assignment. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
2017-06-16 15:59 joerg  Note Edited: 0003774 
2017-06-16 16:05 stephane   Note Added: 0003775  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 15:52 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003774) joerg (reporter) - 2017-06-16 15:52
 http://austingroupbugs.net/view.php?id=1150#c3774 
-- 
Re: http://austingroupbugs.net/view.php?id=1150#c3773

it seems that many shells are broken here...

Does anybody disagree that:

   $SHELL -c 'f() { (exit 3); return $( exit 1); } ; f; echo $?'

should print "3"?

The reason for the diverging behavior is the places where
the shells implement checkpoints to save the current value
of "exitcode" for the next expansion of $?.

The Bourne Shell and it's childs have such a checkpoint at the
end of the interpreter function and this function is called
from the command substitution.

ksh88 removed one such checkpoint after the wait() for the
$(cmd), but left the checkpoint in the interpreter function... 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
2017-06-16 10:21 joerg  Note Edited: 0003771 
2017-06-16 11:07 kreNote Added: 0003772  
2017-06-16 15:38 stephane   Note Added: 0003773  
2017-06-16 15:52 joerg  Note Added: 0003774  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 10:16 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003771) joerg (reporter) - 2017-06-16 10:16
 http://austingroupbugs.net/view.php?id=1150#c3771 
-- 
Re: http://austingroupbugs.net/view.php?id=1150#c3770

The main shell waits for the sub-shell and the exit status remembered
by the main shell is the exit status returned via the wait() or waitid()
call from the sub-shell.

This behavior is responsible for the documented and expected behavior
that resuts in

sh -c 'FOO=$(exit 99); echo $?'

is expected to print 99 while

sh -c 'FOO=$(exit 99) :; echo $?'

is expected to print 0 

If you like to see a different behavior than the one I explained
in http://austingroupbugs.net/view.php?id=1150#c3768, there would be a need to
introduce extra code
to the shell in order to make it behave non-orthogonal.

BTW I wrote http://austingroupbugs.net/view.php?id=1150#c3768 because I know
that:
 
sh -c ': $(exit 99); echo $?'

is expected to print 0. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
2017-06-16 10:16 joerg  Note Added: 0003771  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 10:06 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003770) kre (reporter) - 2017-06-16 10:06
 http://austingroupbugs.net/view.php?id=1150#c3770 
-- 
Re note 3768 ===  It is not nearly as obvious as you think.

In "return $(exit 1)" the "exit 1" is executed in a subshell environment
(that is a requirement), and:

   Changes made to the subshell environment shall not affect the
   shell environment.

That's from XCU 2.12.   The exit status change in the subshell environment
cannot directly affect the shell environment.   The only way to make that
happen would be to export the exit status of the command substitution, and
whether or when that can happen was the subject of the bug report - it is
just not stated, except for the one case in 2.9.1

Most shells (incl ksh93) do the "obvious" thing and return the status of
the last command that occurred, before the return $(exit 1), leaving the
exit status of the command substitution unused, as it is in just about
every
other situation.  Making an exception for this case is exactly the
opposite
to achieving orthogonal behavior.

Your exit 99 examples I agree with, but also remember that

sh -c ': $(exit 99); echo $?' is expected to print 0.

And re note 3769, I believe that in all of STephane's examples, the
$(exit N) should simply be ignored (unless I missed one somewhere).
They produce no output, and were not used in a context where the exit
status of the command substitution should be extracted, so they just turn
into meaningless syntactic noise. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
2017-06-16 10:06 kreNote Added: 0003770  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 09:54 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003769) joerg (reporter) - 2017-06-16 09:54
 http://austingroupbugs.net/view.php?id=1150#c3769 
-- 
Re: http://austingroupbugs.net/view.php?id=1150#c3767

It would be nice if you did post some expected exit status values

Following the behavior of existing shells may be a bad idea, as these
shells may suffer from bugs that we don't like to standardize. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
2017-06-16 09:54 joerg  Note Added: 0003769  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 09:38 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003768) joerg (reporter) - 2017-06-16 09:38
 http://austingroupbugs.net/view.php?id=1150#c3768 
-- 
The standard is obvious here:

If return or exit are called without parameter, the return/exit status
is the status of the last command executed.

Given that with "return $(exit 1)", the last command executed
was "exit 1", it seems to be obvious that the expected return value is 1.

This is important as we like to have an orthogonal behavior and:

sh -c 'FOO=$(exit 99);  echo $?'

is expected to print 99 while

sh -c 'FOO=$(exit 99) :;  echo $?'

is expected to print 0 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
2017-06-16 09:38 joerg  Note Added: 0003768  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 06:10 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003767) stephane (reporter) - 2017-06-16 06:10
 http://austingroupbugs.net/view.php?id=1150#c3767 
-- 
See also

   exit $(exit 1)
   exit < "file$(exit 1)"

in zsh and bash (I suppose the two "popular" shell implementations you're
refering to).

Command-less redirections are also cases to consider:

   < file$(exit 4)
   < file$(exit 5) var=$(exit 6)

Which give different results depending on the shell.

There's also:

   echo < file$(exit 5) "$? $(exit 3)$? $(exit 4)$?"

And:

   var=$(exit 5) eval 'echo "$?"'

And:

   eval 'echo "$?"' < file$(exit 5)

And:

   { echo "$?"; } < file$(exit 5)

And:

   exec 3< file$(exit 5) 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
2017-06-16 06:10 stephane   Note Added: 0003767  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

A NOTE has been added to this issue. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 01:46 UTC
== 
Summary:exit status of command substitution not properly
specified
== 

-- 
 (0003766) kre (reporter) - 2017-06-16 01:46
 http://austingroupbugs.net/view.php?id=1150#c3766 
-- 
Oops, I should have tested my example, when I wrote ...

 set -e; printf %s $( exit 1; printf foo )

I (of course) really meant ...

 set -e; printf %s $( (exit 1); printf foo )

If the exit in there was explicit, rather than just an exit
status, then the -e option setting would be irrelevant.

Alternatively ...

 set -e; printf %s $( false; printf foo )

would have worked as the example. 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kreLine Number   => 75182 - 75224   
2017-06-16 01:46 kreNote Added: 0003766  
==

[1003.1(2016)/Issue7+TC2 0001150]: exit status of command substitution not properly specified

[Austin Group Bug Tracker]

The following issue has been SUBMITTED. 
== 
http://austingroupbugs.net/view.php?id=1150 
== 
Reported By:kre
Assigned To:
== 
Project:1003.1(2016)/Issue7+TC2
Issue ID:   1150
Category:   Shell and Utilities
Type:   Omission
Severity:   Editorial
Priority:   normal
Status: New
Name:   Robert Elz 
Organization:
User Reference:  
Section:2.6.3 
Page Number:2357 - 2358 
Line Number:75182 - 75224 
Interp Status:  --- 
Final Accepted Text: 
== 
Date Submitted: 2017-06-16 01:33 UTC
Last Modified:  2017-06-16 01:33 UTC
== 
Summary:exit status of command substitution not properly
specified
Description: 
The description of Command Substitution (XCU 2.6.3) does not say
what is intended to be done (if anything) with the exit status
of the commands that are performed while evaluating the command
substitution..

There is what is said in 2.9.1 about
a=$(command)
which uses the status of command as the status of the assignment, when
there is no command word, but that is the only case that is explicit.

Normally, it is not going to matter, as when there is a command
(rather than simply ASSIGNMENT_WORDs) the exit status of that command
is explicit in the specification, and does not take any notice of
the exit status of any command substitutions that needed to be
evaluated while preparing to run the command.

For example
: $(exit 1)
has an exit status of 0, because the specification for ':' requires it.
Hence any status from the $() is irrelevant and need not even be
considered.

However there are two issues to consider which are not explicit.

First, does -e apply to the exit status of a command substitution?
I have no doubt that it applies inside the command substitution, so

set -e; printf %s $( exit 1; printf foo )

should output nothing, the command substitution exits when exit returns
status 1, because of the -e (errexit) option being set.

But what about

set -e; printf %s $(exit 1)foo

Everything I have tested prints "foo" here, which I believe is the
intended result, but nothing I can find actually says so.

Second
return $( exit 1 )

After word expansion, we have just

return

as $(exit 1) produces nothing, and is not quoted, so is simply removed.

The specification for "return" says ...
The value of the special parameter '?' shall be set to n, an
unsigned
decimal integer, or to the exit status of the last command
executed
if n is not specified.

Here n is not specified, but is that "exit 1" the last command executed?

The "exit" executes in a sub-shell environment, so cannot be itself, but
the
exit status of the command substitution could be.

Here shells differ, given

$SHELL -c 'f() { return $( exit 1); } ; f; echo $?'

some shells report 1, and some (well, most by number, if not popularity)
0.

My gut feeling is that 0 is correct, but again nothing actually says so.


Desired Action: 
Add a new paragraph, after line 75224 in XCU 2.6.3 (immediately before
section 2.6.4) saying:

   Other than as specified in section 2.9.1 the final exit status of the
   commands executed to perform a command substitution shall not be used
for
   any purpose.  That is a shell shall not exit if the errexit option (-e)
is
   set, and a command substitution fails, though it shall if the result of
the
   command substitution becomes the result of the command as specified in
   section 2.9.1.  Similarly, in any other situation where the exit status
of
   the last or previous command is required, the results of any
intervening
   command substitutions shall be ignored.  Nothing in this paragraph
shall
   affect the commands being executed, or the effect of the errexit option
   upon, the commands executed to perform the command substitution.

== 

Issue History 
Date ModifiedUsername   FieldChange   
== 
2017-06-16 01:33 kreNew Issue
2017-06-16 01:33 kreName  => Robert Elz  
2017-06-16 01:33 kreSection   => 2.6.3   
2017-06-16 01:33 krePage Number   => 2357 - 2358 
2017-06-16 01:33 kre