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Re: [Qemu-devel] [PATCH] configure: save git working tree information in
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH] configure: save git working tree information in "pkgversion" |
Date: |
Tue, 31 May 2016 16:43:46 +0100 |
User-agent: |
Mutt/1.6.0 (2016-04-01) |
On Tue, May 31, 2016 at 05:40:38PM +0200, Laszlo Ersek wrote:
> On 05/31/16 17:14, Daniel P. Berrange wrote:
> > On Tue, May 31, 2016 at 05:04:04PM +0200, Laszlo Ersek wrote:
> >> When building QEMU from a git working tree (either in-tree or
> >> out-of-tree), it is useful to capture the working tree status in the QEMU
> >> binary, for the "-version" option to report.
> >>
> >> Daniel suggested using the "pkgversion" variable (tied to the
> >> "--with-pkgversion" option) of the configure script for this. Downstream
> >> packagers of QEMU already use this option for customizing their builds,
> >> plus libvirtd captures "pkgversion" (with the "-version" option) in
> >> "/var/log/libvirt/qemu/$GUEST.log", whenever a guest is started.
> >>
> >> The information we include in "pkgversion" is the output of git-describe,
> >> with a plus sign (+) appended if there are staged or unstaged changes to
> >> tracked files, at the time of "configure" being executed.
> >>
> >> The content of "pkgversion" is not changed when "--with-pkgversion" is
> >> used on the command line.
> >>
> >> Cc: "Daniel P. Berrange" <address@hidden>
> >> Cc: Kashyap Chamarthy <address@hidden>
> >> Signed-off-by: Laszlo Ersek <address@hidden>
> >> ---
> >> configure | 38 ++++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 38 insertions(+)
> >>
> >> diff --git a/configure b/configure
> >> index b5aab7257b33..20a7ec5cc0fd 100755
> >> --- a/configure
> >> +++ b/configure
> >> @@ -4255,6 +4255,44 @@ if have_backend "dtrace"; then
> >> fi
> >>
> >> ##########################################
> >> +# save git working tree information in pkgversion
> >> +
> >> +# If pkgversion has not been set to a non-empty string, fetch the output
> >> of
> >> +# "git describe" into it. If the working tree is unclean (there are
> >> staged or
> >> +# unstaged changes in tracked files), then append a plus sign.
> >> +#
> >> +# If we're not building from a git working tree, then pkgversion is not
> >> +# changed. Otherwise, git errors are fatal.
> >> +
> >> +if test -z "$pkgversion" && test -d "$source_path/.git"; then
> >> + pkgversion=$(
> >> + export GIT_DIR=$source_path/.git
> >> + export GIT_WORK_TREE=$source_path
> >> +
> >> + git_desc=$(git describe)
> >> + git_exit=$?
> >> + if test $git_exit -ne 0; then
> >> + exit $git_exit
> >> + fi
> >> +
> >> + git_changes=
> >> + for git_diff_option in "" --staged; do
> >> + git diff $git_diff_option --quiet
> >> + git_exit=$?
> >> + case $git_exit in
> >> + (0) ;;
> >> + (1) git_changes=+
> >> + ;;
> >> + (*) exit $git_exit
> >> + ;;
> >> + esac
> >> + done
> >
> > An alternative to this would be to jus use
> >
> > "git describe --dirty"
> >
> > which appends "--dirty" to its output if working tre has uncommitted
> > changes.
>
> Good idea!
>
> > Not sure if the --dirty flag is a recent option or whether we can just
> > assume it always exists.
>
> 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.
Regards,
Daniel
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