fixup! Convert flashrom to git

refine the pre-push hook:
 - get rid of the concept of precious brances - all of them on the
   upstream repos are precious (this is a change in the face of
   using gerrit instead of a native git repository for staging purposes)
 - likewise, only allow new versioned stable branches and no feature
   branches there

Change-Id: I1d4b4a7ef2673cabee980ec4a7d7d5fbebdcaed1
Signed-off-by: Stefan Tauner <stefan.tauner@gmx.at>
Reviewed-on: https://review.coreboot.org/21834
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/util/git-hooks/pre-push b/util/git-hooks/pre-push
index 5bae8d2..b5f4620 100755
--- a/util/git-hooks/pre-push
+++ b/util/git-hooks/pre-push
@@ -22,15 +22,21 @@
 zero=0000000000000000000000000000000000000000
 
 upstream_pattern="github\.com.flashrom/flashrom(\.git)?|flashrom\.org.git/flashrom(\.git)?"
-precious_branches="stable staging"
 
-# Only care about the upstream repository
+# Only care about the upstream repositories
 if echo "$url" | grep -q -v -E "$upstream_pattern" ; then
 	exit 0
 fi
 
 while read local_ref local_sha remote_ref remote_sha ; do
-	if [ "$remote_ref" != "refs/heads/staging" -a "$remote_ref" != "refs/heads/stable" ]; then
+
+	# Only allow the stable and staging branches as well as versioned stable branches (e.g., 0.0.x).
+	# The matching expression's RE is always anchored to the first character (^ is undefined).
+	# The outer parentheses are needed to print out the whole matched string.
+	version=$(expr ${remote_ref#*refs/heads/} : '\(\([0-9]\+\.\)\{2,\}x\)$')
+	if [ "$remote_ref" != "refs/heads/staging" ] && \
+	   [ "$remote_ref" != "refs/heads/stable" ] && \
+	   [ -z "$version" ]; then
 		echo "Feature branches not allowed ($remote_ref)." >&2
 		exit 1
 	fi
@@ -40,14 +46,10 @@
 		exit 1
 	fi
 
-	if [ "$remote_sha" = "$zero" ]; then
-		echo "No new branches allowed." >&2
-		exit 1
-	fi
-
 	# Check for Signed-off-by and Acked-by
 	commit=$(git rev-list -n 1 --all-match --invert-grep -E \
-		--grep '^Signed-off-by: .+ <.+@.+\..+>$' --grep '^Acked-by: .+ <.+@.+\..+>$' \
+		--grep '^Signed-off-by: .+ <.+@.+\..+>$' \
+		--grep '^Acked-by: .+ <.+@.+\..+>$' \
 		"$remote_sha..$local_sha")
 	if [ -n "$commit" ]; then
 		echo "Commit $local_sha in $local_ref is missing either \"Signed-off-by\"" \
@@ -55,17 +57,16 @@
 		exit 1
 	fi
 
-	# Make _really_ sure we do not rewrite precious history
-	for lbranch in $precious_branches ; do
-		if [ "$remote_ref" = "refs/heads/$lbranch" ]; then
-			nonreachable=$(git rev-list $remote_sha ^$local_sha | head -1)
-			if [ -n "$nonreachable" ]; then
-				echo "Only fast-forward pushes are allowed on $lbranch." >&2
-				echo "$nonreachable is not included in $remote_sha while pushing to $remote_ref" >&2
-				exit 1
-			fi
+	# Make _really_ sure we do not rewrite history of any head/branch
+	if [ "${remote_ref#*refs/heads/}" != "$remote_ref" ]; then
+		nonreachable=$(git rev-list $remote_sha ^$local_sha | head -1)
+		if [ -n "$nonreachable" ]; then
+			echo "Only fast-forward pushes are allowed on branches." >&2
+			echo "At least $nonreachable is not included in $remote_sha while pushing to " \
+			     "$remote_ref" >&2
+			exit 1
 		fi
-	done
+	fi
 
 	# FIXME: check commit log format (subject without full stop at the end etc).
 	# FIXME: do buildbot checks if authorized?