Minutes of the 17th October 2019 Teleconference

[Andrew Josey]

All
Enclosed are the minutes from the thursday call this week
regards
Andrew
-

Minutes of the 17th October 2019 Teleconference Austin-977 Page 1 of 1
Submitted by Andrew Josey, The Open Group. 19th October 2019

Attendees:
Nick Stoughton, USENIX, ISO/IEC JTC 1/SC 22 OR
Andrew Josey, The Open Group
Don Cragun, IEEE PASC OR
Geoff Clare, The Open Group
Joerg Schilling, FOKUS Fraunhofer
Eric Blake, Red Hat, Open Group OR
Mark Ziegast, SHware Systems Dev.

* General news 

Andrew gave a demonstration of the gitlab setup for maintaining the
source for the documentation.  This will allow for branches to be
built with a continuous build pipeline.
Andrew took an action to have the regular core team members added
to the gitlab project (completed after the call)

* Outstanding actions

(Please note that this section has been flushed to shorten the minutes -
to locate the previous set of outstanding actions, look to the minutes
from 13th June 2019 and earlier)

Bug 1254: "asynchronous list" description uses "command" instead of "AND-OR 
list" OPEN
http://austingroupbugs.net/view.php?id=1254
Action: Joerg to investigate how his shell behaves.

Bug 700 - Nick to raise this issue with the C committee
Bug 713 - Nick to raise with the C committee.
Bug 739 - Nick to raise with the C committee.
Bug 1216 - Eric to ask if The Open Group is willing to sponsor this interface, 
referencing bug note 4478.


* Current Business

Bug 1293: Add methods associated with manipulating pthread affinity on SMP 
systems Rejected
http://austingroupbugs.net/view.php?id=1293

This was discussed during the 2019-10-17 conference call: As noted
in Note: 0004574, this problem has very hardware specific issues.
Since the POSIX standards are not intended to be hardware specific,
we do not feel that this is an appropriate set of interfaces to be
included at this time... If another standards body does produce a
standard in this area that provides generic hardware support, we
will then consider referencing that standard the same way POSIX.1-2018
references the 1999 C Standard.

But also note that this seems to be a type of system configuration
and resource availability issue that is specifically listed as
outside the scope of the current standard in Section 1.1 Scope in
the Introduction to the current standard. OpenMP is a group that
is working in this area.

This enhancement request is rejected. 

Bug 1294: POSIX recognizes the existence of dynamically loadable, executable 
object files, but provides no way of producing them. OPEN
http://austingroupbugs.net/view.php?id=1294

This was discussed on the call and will be continued next time.
Next Steps 
--
The next calls are on:

October 21 2019 (Monday)
This call will be for 60 minutes.

October 24 2019 (Thursday)
This call will be for 90 minutes.

Apologies in advance:
Nick Stoughton, 2019-10-21, 2019-10-24
Eric Blake,  2019-10-28, 2019-10-31

Calls are anchored on US time. (8am Pacific) 

Please check the calendar invites for dial in details.
http://austingroupbugs.net

An etherpad is usually up for the meeting, with a URL using the date format as 
below:

https://posix.rhansen.org/p/201x-mm-dd
username=posix password=2115756#



Andrew JoseyThe Open Group
Austin Group Chair  
Email: a.jo...@opengroup.org 
Apex Plaza, Forbury Road,Reading,Berks.RG1 1AX,England

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Re: [1003.1(2016)/Issue7+TC2 0001234]: in most shells, backslash doesn't have two meaning wrt pattern matching

[Harald van Dijk]

On 23/09/2019 16:39, Austin Group Bug Tracker wrote:

--
  (0004564) geoffclare (manager) - 2019-09-23 15:39
  http://austingroupbugs.net/view.php?id=1234#c4564
--
Interpretation response

[...]
If a pattern ends with an unescaped , the behavior is
unspecified.


Another problem here, one that already exists in the current wording:

For patterns used for filename expansion, in current shells that treat 
unescaped backslash as an escape character, behaviour is inconsistent 
when unescaped backslash appears before a forward slash.


Shells appear to typically implement 2.13.3 by effectively splitting 
strings on forward slashes, then interpreting each component as a 
pattern if needed. This results in some components ending with an 
unescaped backslash.


In bash 5, an indirect [a]\/b will find a file named 'b' in a directory 
named 'a\', but an indirect a\/[b] will find a file named 'b' in a 
directory named 'a'. An indirect a\/b (which would not trigger pathname 
expansion under the new wording), meanwhile, found a/b in bash 5 up to 
patchlevel 2, then changed to a\/b as of patchlevel 3.


In bash 4, an indirect [a]\/b will not find any files, but an indirect 
a\/[b] will find a file named 'b' in a directory named 'a'.


In nbsh, an indirect [a]\/b will not find any files, but an indirect 
a\/[b] will find a file named 'b' in a directory named 'a\'. (In nbsh, 
whether backslash acts as an escape character is currently determined 
per pathname component, as mentioned earlier.)


However, 2.13.3 does not specify that strings are split on forward 
slashes, so by the description in the standard, these patterns do not 
end in an unescaped backslash. As such, I believe the current and 
proposed wording requires treating the backslash as escaping the slash, 
which is not supposed to have any effect. I believe the required 
behaviour is that indirect [a]\/b and a\/[b] both find a file named 'b' 
in a directory named 'a'.


Is my understanding correct? If so, should these patterns become 
unspecified as well, to allow current and older shell behaviour?


Cheers,
Harald van Dijk