Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-16 Thread Philip Oakley

From: Junio C Hamano gits...@pobox.com
Sent: Monday, April 15, 2013 2:39 AM

Philip Oakley philipoak...@iee.org writes:


If the parsing is done for white/blacklist purposes, is there a
need to straight-jacket the verison string format like this series?


The purpose is to document what we felt we could guarantee, and that
which was open to variation, so that those, like the Git-Gui, can
code
in a sensible check for the version. Two digits (X.Y) should pass the
existing Git Gui check.

I'll drop the length limit, and keep to an X.Y check

Is the end of t-basic.sh a sensible place for the check?


Sorry, but I still do not understand what you are trying to achieve.

What kind of benefit are you envisioning out of this?


The purpose of tests is to detect mistakes and spot regressions.

A change to the 'git version X.Y.z' string would be a regression, as I 
spotted earlier, as it conflicts with expectations of standard 
programmes such as git-gui.



For a future
version, people would not know what incompatibilities it would
introduce, so

case $(git version) in
git verison[2-9].*)
   echo unsupported version
   exit 1
   ;;
esac

is a nonsense check.

For all released versions, people know how they looked like
and we
do not have anything further to specify.  Git 1.5.0 will forever
identify itself as:

$ git version
   git version 1.5.0

Worse yet, for an untagged version, you may get something like

git version 1.8.2.1-515-g78d2372


However, if it passes the test [all the tests], one expects it will be 
reasonably (almost completely) compatibility with external expectations, 
such as those of git gui.


The questions I'm posing is from the other direction - use of tests for 
quality control.




and it may or may not behave the same way as 1.8.2.1 depending on
what trait you are interested in.


That will depend on the tests if [deliberately?] failed.

I'll tidy up the patches and commit meesage and see how it looks then.

Philip

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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-16 Thread Junio C Hamano
Philip Oakley philipoak...@iee.org writes:

 What kind of benefit are you envisioning out of this?

 The purpose of tests is to detect mistakes and spot regressions.

 A change to the 'git version X.Y.z' string would be a regression, as I
 spotted earlier, as it conflicts with expectations of standard
 programmes such as git-gui.

Sorry, but I do not follow.

A released version says git version 1.8.2.1.  In a month or so,
I'll have another one that says git version 1.8.3.  Or I may
decide to bump in preparation for 2.0 and it may identify itself as
git version 1.9.

Neither of which no existing program such as git-gui has ever
seen.

In what way is that a regression?

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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-16 Thread David Aguilar
On Tue, Apr 16, 2013 at 11:12 AM, Junio C Hamano gits...@pobox.com wrote:

 Philip Oakley philipoak...@iee.org writes:

  What kind of benefit are you envisioning out of this?
 
  The purpose of tests is to detect mistakes and spot regressions.
 
  A change to the 'git version X.Y.z' string would be a regression, as I
  spotted earlier, as it conflicts with expectations of standard
  programmes such as git-gui.

 Sorry, but I do not follow.

 A released version says git version 1.8.2.1.  In a month or so,
 I'll have another one that says git version 1.8.3.  Or I may
 decide to bump in preparation for 2.0 and it may identify itself as
 git version 1.9.

 Neither of which no existing program such as git-gui has ever
 seen.

 In what way is that a regression?

Sorry.  I was the one that first suggested that this was an issue.

The regression is that there are scripts and tools in the wild that
need to know the git version when deciding whether or not to use some
new feature.

e.g. git status --ignore-submodules=dirty did not appear until git 1.7.2.
A script may want to use this flag, but it will only want to use it
when available.

If this string started saying The Git Version Control System v2.0 then these
scripts would be broken since they would no longer recognize this as a
post-1.7.2 Git.

The unstated suggestion here is that it may be helpful to others if we
were to declare that the git version output is plumbing.

Folks are already using it that way so making it official would provide
a guarantee that we won't break them in the future.
--
David
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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-16 Thread Junio C Hamano
David Aguilar dav...@gmail.com writes:

 The regression is that there are scripts and tools in the wild that
 need to know the git version when deciding whether or not to use some
 new feature.

 e.g. git status --ignore-submodules=dirty did not appear until git 1.7.2.
 A script may want to use this flag, but it will only want to use it
 when available.

 If this string started saying The Git Version Control System v2.0 then these
 scripts would be broken since they would no longer recognize this as a
 post-1.7.2 Git.

Blacklisting known-bad version and hoping all other versions
including the ones you have never seen to behave in the way you
expect usually works but there is a limit.

A change to say The Git Version Control System %s will not happen
willy-nilly, but when there is a good reason to do so, we would.

I do not think a test that hardcodes the output is a good way to
make sure a change is being done with a good reason.  After all, a
patch that updates the git version %s string can just update the
expected output in the same patch.  The only reason such a change
will be caught is because during the review, somebody notices that
the change touches the expected output of a test; for that to
reliably protect the output, the test *has* to be commented to say
that this expected output should be changed very carefully.

A much better solution would be to leave that very carefully
comment next to the in-code string to warn people about ramifiations
of changing it.


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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-16 Thread Philip Oakley

From: Junio C Hamano gits...@pobox.com
Sent: Tuesday, April 16, 2013 7:12 PM

Philip Oakley philipoak...@iee.org writes:


What kind of benefit are you envisioning out of this?


The purpose of tests is to detect mistakes and spot regressions.

A change to the 'git version X.Y.z' string would be a regression, as 
I

spotted earlier, as it conflicts with expectations of standard
programmes such as git-gui.


Sorry, but I do not follow.

A released version says git version 1.8.2.1.  In a month or so,
I'll have another one that says git version 1.8.3.  Or I may
decide to bump in preparation for 2.0 and it may identify itself as
git version 1.9.

Neither of which no existing program such as git-gui has ever
seen.

In what way is that a regression?


But they both pass the test and test suite, yes? And even if you use 
git-gui with them, git-gui will not barf on start up, which it would if 
the version string fails my test.


Passing the test suite should be a reasonble guarantee that co-tools 
will work, including those that check for version. This is a check for 
that version string.


However if someone[1] creates My Special Git Version 1-9-3 (Index 
V7b), and here I'm suggesting they may have other special changes, then 
the version check will tell them that even when they have fixed their 
special changes to pass the other parts of the test suite, other 
co-tools could barf.


Its about pushing the piece of string from the users end ;-) It also 
stops others trying to change 'git' to 'Git' within this message, just 
as I did.


Philip


[1] my first draft had 'you', but that is not a reasonable starting 
position. It's more about *others* attempting to create release 
versions, which announce their name, that we expect to be compatible 
with say git-gui (via the rest of the test suite), and need to check 
that announcement. 


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[RFC/PATCH 0/2] Test the Git version string

2013-04-14 Thread Philip Oakley
In $gmane/217004 I was noted that the git version string is used
in the wild for confirming which git version is in use.

This patch series seeks to add tests for the version string format
and document it.

The key questions to be answered are:
* should the test be inside t, or somewhere else?
* should the version string be limited to one line, 80 characters?
* how to format the asciidoc of the ERE.

Philip Oakley (2):
  test git version string
  Doc: State the exact git version string

 Documentation/git.txt | 4 
 t/t-basic.sh  | 8 
 2 files changed, 12 insertions(+)

-- 
1.8.1.msysgit.1

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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-14 Thread Junio C Hamano
Philip Oakley philipoak...@iee.org writes:

 This patch series seeks to add tests for the version string format
 and document it.

 The key questions to be answered are:
 * should the test be inside t, or somewhere else?
 * should the version string be limited to one line, 80 characters?

One line, perhaps, but I do not think any byte-limit is reasonable.

It is unreasonable to limit the form to X.Y.Z; after we hit Git 2.0,
it is likely that we would go to two-decimals.

If the parsing is done for white/blacklist purposes, is there a
need to straight-jacket the verison string format like this series?
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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-14 Thread Philip Oakley

From: Junio C Hamano gits...@pobox.com
Sent: Sunday, April 14, 2013 8:22 PM

Philip Oakley philipoak...@iee.org writes:


This patch series seeks to add tests for the version string format
and document it.

The key questions to be answered are:
* should the test be inside t, or somewhere else?
* should the version string be limited to one line, 80 characters?


One line, perhaps, but I do not think any byte-limit is reasonable.


OK



It is unreasonable to limit the form to X.Y.Z; after we hit Git 2.0,
it is likely that we would go to two-decimals.


Ah. And then maintenance releases could be the .Z maybe. I suppose it 
will depend on circumstances.




If the parsing is done for white/blacklist purposes, is there a
need to straight-jacket the verison string format like this series?


The purpose is to document what we felt we could guarantee, and that 
which was open to variation, so that those, like the Git-Gui, can code 
in a sensible check for the version. Two digits (X.Y) should pass the 
existing Git Gui check.


I'll drop the length limit, and keep to an X.Y check

Is the end of t-basic.sh a sensible place for the check?


--
Philip 


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Re: [RFC/PATCH 0/2] Test the Git version string

2013-04-14 Thread Junio C Hamano
Philip Oakley philipoak...@iee.org writes:

 If the parsing is done for white/blacklist purposes, is there a
 need to straight-jacket the verison string format like this series?

 The purpose is to document what we felt we could guarantee, and that
 which was open to variation, so that those, like the Git-Gui, can code
 in a sensible check for the version. Two digits (X.Y) should pass the
 existing Git Gui check.

 I'll drop the length limit, and keep to an X.Y check

 Is the end of t-basic.sh a sensible place for the check?

Sorry, but I still do not understand what you are trying to achieve.

What kind of benefit are you envisioning out of this?  For a future
version, people would not know what incompatibilities it would
introduce, so

case $(git version) in
git verison[2-9].*)
echo unsupported version
exit 1
;;
esac

is a nonsense check.

For all released versions, people know how they looked like and we
do not have anything further to specify.  Git 1.5.0 will forever
identify itself as:

$ git version
git version 1.5.0

Worse yet, for an untagged version, you may get something like

git version 1.8.2.1-515-g78d2372

and it may or may not behave the same way as 1.8.2.1 depending on
what trait you are interested in.
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