Re: [Qemu-devel] [PATCH] configure: save git working tree information in "pkgversion"

[Laszlo Ersek]

On 05/31/16 19:45, Eric Blake wrote:
> On 05/31/2016 11:01 AM, Laszlo Ersek wrote:
> 
>>>> Grepping git's Documentation/RelNotes/ directory, I find:
>>>> - in "1.6.6.txt": the introduction of --dirty
>>>> - in "1.7.6.4.txt": an apparently important bugfix for --dirty

(*)

>>>>
>>>> Version 1.7.6.4 of git was tagged on Sep 23 2011.
>>>>
>>>> Does this information help in deciding if we can use --dirty?
>>>
>>> 5 years old sounds new enough for my liking :-)
>>>
>>> I guess we could use --dirty and catch the non-zero exit code and just
>>> re-try without --dirty.
>>
>> But, if we can't use --dirty, I should probably use the plus-sign
>> fallback (we need *something* to mark a dirty state).
>>
>> In which case however, shouldn't we just go with the current patch,
>> which doesn't care about --dirty at all? Otherwise, some build hosts
>> will append "-dirty", and others will append "+".
>>
>> IMO we should either require --dirty, or go with the current patch.
> 
> Gnulib's build-aux/git-version-gen script doesn't yet use --dirty, but
> may be an inspiration for how to generate the same suffix:
> 
> # Test whether to append the "-dirty" suffix only if the version
> # string we're using came from git.  I.e., skip the test if it's "UNKNOWN"
> # or if it came from .tarball-version.
> if test "x$v_from_git" != x; then
>   # Don't declare a version "dirty" merely because a time stamp has changed.
>   git update-index --refresh > /dev/null 2>&1

(
This is exactly the fix (*) that went into git v1.7.6.4 (and v1.7.7):

$ git log --oneline --reverse v1.7.6.3..v1.7.6.4

0f64bfa9567f ls-files: fix pathspec display on error
e9d4f7405b6a branch.c: use the parsed branch name
13d6ec913330 read_gitfile_gently(): rename misnamed function to read_gitfile()
9b0ebc722cfc clone: allow to clone from .git file
dbc92b072dd7 clone: allow more than one --reference
e6baf4a1ae1b clone: clone from a repository with relative alternates
2f633f41d695 check-ref-format --print: Normalize refnames that start with 
slashes
f3738c1ce919 Forbid DEL characters in reference names
385ceec1cb46 t3005: do not assume a particular order of stdout and stderr of 
git-ls-files
dff4b0ef30cd am: format is in $patch_format, not parse_patch
e622f41dcd97 git-mergetool: check return value from read
40ffc4987661 Merge branch 'gb/maint-am-patch-format-error-message' into maint
503359f13abc Merge branch 'mg/branch-set-upstream-previous' into maint
be5acb3b63af Merge branch 'mh/check-ref-format-print-normalize' into maint
406c1c4dd4a8 Merge branch 'nd/maint-clone-gitdir' into maint
84b051462fca Merge branch 'jc/maint-clone-alternates' into maint
85b3c75f4fd3 describe: Refresh the index when run with --dirty
a0b1cb60ab29 Merge branch 'cb/maint-ls-files-error-report' into maint
632052641517 Git 1.7.6.4

--> https://github.com/git/git/commit/85b3c75f4fd3
    "describe: Refresh the index when run with --dirty"
)

> 
>   dirty=`exec 2>/dev/null;git diff-index --name-only HEAD` || dirty=
>   case "$dirty" in
>       '') ;;
>       *) # Append the suffix only if there isn't one already.
>           case $v in
>             *-dirty) ;;
>             *) v="$v-dirty" ;;
>           esac ;;
>   esac
> fi

This seems to do the right thing, yes.

I'll submit a new version later.

Thanks!
Laszlo