git-version-gen: add --fallback option to use if git is not present

When building in a git checkout, but from a system lacking git, it
is useful to fall back to the version determined when the git
checkout was last used from a system sporting git.

* build-aux/git-version-gen: Add support for the new option --fallback,
which comes into play when there is no $tarball_version_file and
git is not working.
(scriptversion): Update.

Copyright-paperwork-exempt: yes
Signed-off-by: Peter Rosin <peda@lysator.liu.se>

diff --git a/ChangeLog b/ChangeLog
index 596762c..622211e 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2012-12-31  Peter Rosin  <peda@lysator.liu.se>  (tiny change)
 
+       git-version-gen: add --fallback option to use if git is not present
+       * build-aux/git-version-gen: Add support for the new option --fallback,
+       which comes into play when there is no $tarball_version_file and
+       git is not working.
+       (scriptversion): Update.
+
        maint.mk: handle missing git with more grace
        * top/maint.mk (no-submodule-changes, public-submodule-commit):
        Quietly proceed if git is not present.

diff --git a/build-aux/git-version-gen b/build-aux/git-version-gen
index 0fa9063..9152baa 100755 (executable)
--- a/build-aux/git-version-gen
+++ b/build-aux/git-version-gen
@@ -1,6 +1,6 @@
 #!/bin/sh
 # Print a version string.
-scriptversion=2012-03-18.17; # UTC
+scriptversion=2012-12-31.22; # UTC
 
 # Copyright (C) 2007-2012 Free Software Foundation, Inc.
 #
@@ -86,6 +86,7 @@ Print a version string.
 Options:
 
    --prefix           prefix of git tags (default 'v')
+   --fallback         fallback version to use if \"git --version\" fails
 
    --help             display this help and exit
    --version          output version information and exit
@@ -93,12 +94,14 @@ Options:
 Running without arguments will suffice in most cases."
 
 prefix=v
+fallback=
 
 while test $# -gt 0; do
   case $1 in
     --help) echo "$usage"; exit 0;;
     --version) echo "$version"; exit 0;;
     --prefix) shift; prefix="$1";;
+    --fallback) shift; fallback="$1";;
     -*)
       echo "$0: Unknown option '$1'." >&2
       echo "$0: Try '--help' for more information." >&2
@@ -184,8 +187,10 @@ then
     # Remove the "g" in git describe's output string, to save a byte.
     v=`echo "$v" | sed 's/-/./;s/\(.*\)-g/\1-/'`;
     v_from_git=1
-else
+elif test -z "$fallback" || git --version >/dev/null 2>&1; then
     v=UNKNOWN
+else
+    v=$fallback
 fi
 
 v=`echo "$v" |sed "s/^$prefix//"`