git-synchronizer: only force-push when necessary

dscho · dscho · commit cf0e7bc94fd3 · 2014-05-22T18:41:28.000-05:00
This helps with SourceForge: SourceForge has this ridiculously
restrictive configuration that disallows non-fast-forward pushes,
even to branches other than 'master'. This cannot even be changed
by project administrators.

As a work-around, we delete branches just before force-pushing them
when we detect that the force-push targets SourceForge.

However, we marked too many pushes as forced pushes, including
fast-forwarding ones to the master branch. And ran into another
restriction (one that actually does make sense): you cannot delete
the current branch.

So let's be extra careful to determine whether it is *actually*
a forced push, or whether it is really a fast-forward.

Signed-off-by: Johannes Schindelin &lt;johannes.schindelin@gmx.de&gt;
diff --git a/git-synchronizer.sh b/git-synchronizer.sh
@@ -252,9 +252,16 @@ do
 					echo ":refs/heads/$ref"
 				fi
 			else
-				if test ${sha1#+} != "$(git rev-parse $remoteref 2> /dev/null)"
+				sha1=${sha1#+}
+				if test $sha1 != "$(git rev-parse $remoteref 2> /dev/null)"
 				then
-					echo "$sha1:refs/heads/$ref"
+					if test -n "$(git rev-list "$sha1..$remoteref")"
+					then
+						# really need to force
+						echo "+$sha1:refs/heads/$ref"
+					else
+						echo "$sha1:refs/heads/$ref"
+					fi
 				fi
 			fi
 		done)
