meson-vcs-tag: enhance version info generation

When build from release tarball and where there is parent .git dir,
this situtaion will get wrong version info. (build with buildroot)

The systemd running show wrong version in dmesg log:
systemd[1]: systemd 2019.02-1086-gf5f17c4 running in system mode.
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Shoule be:
systemd[1]: systemd 241 running in system mode. (-PAM -AUDIT -SEL
            ^^^^^^^^^^^

diff --git a/tools/meson-vcs-tag.sh b/tools/meson-vcs-tag.sh
index a8605b6bc94167b6ea2df7dc265be171da1c7e53..5dc95fa8c15ad4fd61a84c5ade936010c8594482 100755 (executable)
--- a/tools/meson-vcs-tag.sh
+++ b/tools/meson-vcs-tag.sh
@@ -15,4 +15,8 @@ fi
 # Apparently git describe has a bug where it always considers the work-tree
 # dirty when invoked with --git-dir (even though 'git status' is happy). Work
 # around this issue by cd-ing to the source directory.
-cd "$dir" && git describe --abbrev=7 --dirty=+ 2>/dev/null | sed 's/^v//' || echo "$fallback"
+cd "$dir"
+# Check that we have either .git/ (a normal clone) or a .git file (a work-tree)
+# and that we don't get confused if a tarball is extracted in a higher-level
+# git repository.
+[ -e .git ] && git describe --abbrev=7 --dirty=+ 2>/dev/null | sed 's/^v//' || echo "$fallback"