[PATCH] MODULES.html.sh: handle tarball builds

[PATCH] MODULES.html.sh: handle tarball builds

[Bernhard M. Wiedemann]

Distributions typically build binaries from release tarballs
that do not contain a .git directory.
In such a setup the git log would fail.
This patch provides a fallback that still allows for reproducibility.

See https://reproducible-builds.org/specs/source-date-epoch/
for the definition of this variable.

This also replaces the git log line with a simpler equivalent.

CC: Bruno Haible <bruno@clisp.org>
---
 MODULES.html.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/MODULES.html.sh b/MODULES.html.sh
index b1638dada..0151670cc 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -3695,7 +3695,10 @@ func_echo '<LI>A POT file and some PO files'
 func_end UL
 
 func_echo '<HR>'
-git_checkout_date=`git log -n 1 --date=iso --format=fuller | sed -n -e 's/^CommitDate: //p'`
+git_checkout_date=`PAGER= git log -n 1 --format=%ci`
+if [ -z "$git_checkout_date" ] ; then
+  git_checkout_date=@${SOURCE_DATE_EPOCH:-`date +%s`}
+fi
 pretty_date=`LC_ALL=C date +"%e %B %Y" --date="$git_checkout_date"`
 func_echo "Generated by <CODE>MODULES.html.sh</CODE> from a git checkout as of ${pretty_date}."
 
-- 
2.16.4

Re: [PATCH] MODULES.html.sh: handle tarball builds

[Bruno Haible]

Hi Bernhard,

> Distributions typically build binaries from release tarballs
> that do not contain a .git directory.
> In such a setup the git log would fail.

I did not know that, as I'm not in the distro business.

> This patch provides a fallback that still allows for reproducibility.

As I wrote in
   <https://lists.gnu.org/archive/html/bug-gnulib/2020-03/msg00061.html>,
the date is important for the readers of the generated file.

If the .git directory is not present, let's use the ChangeLog instead.


2020-04-10  Bruno Haible  <bruno@clisp.org>

	MODULES.html.sh: Support for reproducible builds from git-less tarballs.
	Reported by Bernhard M. Wiedemann <bwiedemann@suse.de> in
	<https://lists.gnu.org/archive/html/bug-gnulib/2020-03/msg00061.html>.
	* MODULES.html.sh: In a git-less tarball, use the date of the first
	ChangeLog entry.

diff --git a/MODULES.html.sh b/MODULES.html.sh
index b1638da..d1ec78f 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -3695,7 +3695,11 @@ func_echo '<LI>A POT file and some PO files'
 func_end UL
 
 func_echo '<HR>'
-git_checkout_date=`git log -n 1 --date=iso --format=fuller | sed -n -e 's/^CommitDate: //p'`
+git_checkout_date=`if test -d .git; then
+                     git log -n 1 --date=iso --format=fuller | sed -n -e 's/^CommitDate: //p';
+                   else
+                     sed -n -e 's/^\([0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]\).*/\1/p' -e 1q ChangeLog;
+                   fi`
 pretty_date=`LC_ALL=C date +"%e %B %Y" --date="$git_checkout_date"`
 func_echo "Generated by <CODE>MODULES.html.sh</CODE> from a git checkout as of ${pretty_date}."