GIT-VERSION-GEN gives "-dirty" when file metadata changed

Hello,

Today I've created custom Debian packages from Git for the first time (yes I know there are Debian packages already, I'm doing it so that I can patch Git and still have the convenience of a package system), using the 1.6.0.rc2 checkout, and using my normal procedure to build debian source packages (running "dpkg-buildpackage -uc -us -b -rfakeroot" as non-root user). The resulting binary reported for --version the string "1.6.0.rc2-dirty"; I wondered why, since I didn't have uncommitted changes neither in the working dir nor in the index. I found that the GIT-VERSION-GEN script would check for a clean working directory by checking that "git diff-index --name-only HEAD --" does not report any files, and since this is now running under the control of the fakeroot process, all files had owner 
 and group 0, whereas in reality (when I made the checkout) they had a non-root uid/gid. This made diff-index report all files, and hence give the "-dirty" version.

I'll followup this mail with two variants of a patch which runs "git update-index --refresh" before that check, which solves the issue. Patch A just does it always, patch B does it only if the metadata check failed; I've created the latter with the idea in mind that update-index might be too costly in some situation (here it's fast but I don't know about people without much RAM).

Perhaps not many people are building Git with the help of fakeroot, but I don't see why the patch would hurt either, and it seems to me like it's implementing the correct behaviour (metadata changes could also happen should anyone or some build process move or copy the files to another place before building, or similar). I don't know whether the Debian Git package maintainer had another solution, but maybe his packages are simply being built as root without the help of "fakeroot" (cc to him for information).

Christian.

When building under the control of the "fakeroot" tool [*], as is the
case when building a Debian package using "dpkg-buildpackage
-rfakeroot", GIT-VERSION-GEN appended "-dirty" to the version number;
this happens because "git diff-index --name-only HEAD --" would report
all files as changed if they have a non-root owner/group, since they
appear as owned by root under fakeroot, leading to non-empty
output. Refreshing the index first makes the decision based on content
changes only.

[*] http://fakeroot.alioth.debian.org/

Signed-off-by: Christian Jaeger <redacted>
---
 GIT-VERSION-GEN |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index cb7cd4b..e6ff486 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN

@@ -16,6 +16,7 @@ elif test -d .git -o -f .git &&
 	case "$VN" in
 	*$LF*) (exit 1) ;;
 	v[0-9]*)
+		git update-index --refresh
 		test -z "$(git diff-index --name-only HEAD --)" ||
 		VN="$VN-dirty" ;;
 	esac

-- 
1.6.0.rc2.1.g7e734

When building under the control of the "fakeroot" tool [*], as is the
case when building a Debian package using "dpkg-buildpackage
-rfakeroot", GIT-VERSION-GEN appended "-dirty" to the version number;
this happens because "git diff-index --name-only HEAD --" would report
all files as changed if they have a non-root owner/group, since they
appear as owned by root under fakeroot, leading to non-empty
output. Refreshing the index first makes the decision based on content
changes only.

[*] http://fakeroot.alioth.debian.org/

Signed-off-by: Christian Jaeger <redacted>
---
 GIT-VERSION-GEN |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index cb7cd4b..fb3e2d8 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN

@@ -17,6 +17,12 @@ elif test -d .git -o -f .git &&
 	*$LF*) (exit 1) ;;
 	v[0-9]*)
 		test -z "$(git diff-index --name-only HEAD --)" ||
+		{
+			# some metadata of files has changed; what
+			# about the contents?
+			git update-index --refresh
+			test -z "$(git diff-index --name-only HEAD --)"
+		} ||
 		VN="$VN-dirty" ;;
 	esac
 then

-- 
1.6.0.rc2.1.g7e734