[PATCH] dim: basic Fixes: check

[Daniel Vetter]

Somewhat inspired by Stephen Rotwell's code, but because random
unfriendly encounters with bash it ended up looking quite a bit
different. Also only really checks sha1 for now, but that should be
good enough.

v2: Actually forward the error code from the subshell (which was
automatically created because of the pipeline, now I made it
explicit). Spotted by shellcheck, somehow I didn't notice that my
checks didn't actually abort the pull in my testing.

v3:
- quiet some noise in the output
- also check sha1 length and whether the subject matches. That latter
  check is a bit more strict than what sfr uses, but matches what dim
  cite produces.

Cc: Dave Airlie <airlied at linux.ie>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 dim | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/dim b/dim
index 4ee94fc2798b..10f823283b55 100755
--- a/dim
+++ b/dim
@@ -795,6 +795,66 @@ function dim_rebuild_tip
 	commit_rerere_cache
 }
 
+function checkpatch_fixes_tag
+{
+	local sha1 fixes_lines cite rv fline
+
+	sha1=$1
+	rv=0
+	fixes_lines=$(git log -1 --format='%B' "$sha1" | grep -i '^[[:space:]]*Fixes:')
+	cite=$(dim_cite $sha1)
+
+	echo "$fixes_lines" | ( local rv; rv=0 ; while read -r fline; do
+		local fixes_sha1 fixes_subject orig_subject
+		if [[ -z "$fline" ]] ; then
+			continue
+		fi
+
+		[[ "$fline" =~ ^[[:space:]]*[Ff][Ii][Xx][Ee][Ss]:[[:space:]]*(.*)$ ]]
+		fline="${BASH_REMATCH[1]}"
+
+		if [[ ! "$fline" =~ ^[[:space:]]*([[:xdigit:]]{5,})[[:space:]]*(.*)$ ]]; then
+			echoerr "$cite: Malformed fixes line:"
+			echoerr "    $fline"
+			rv=1
+			continue
+		fi
+		fixes_sha1="${BASH_REMATCH[1]}"
+		fixes_subject="${BASH_REMATCH[2]}"
+
+		if ! git rev-parse --verify -q $fixes_sha1 > /dev/null ; then
+			echoerr "$cite: SHA1 in fixes line not found:"
+			echoerr "    $fline"
+			rv=1
+			continue
+		fi
+		if ! git merge-base --is-ancestor $fixes_sha1 $sha1 ; then
+			echoerr "$cite: Fixes: SHA1 in not pointing at an ancestor:"
+			echoerr "    $fline"
+			rv=1
+			continue
+		fi
+		if ! echo $fixes_sha1 | grep -q '[[:xdigit:]]\{12\}' ; then
+			echoerr "$cite: Fixes: SHA1 needs at least 12 digits:"
+			echoerr "    $fline"
+			rv=1
+			continue
+		fi
+		orig_subject=$(git show -s $fixes_sha1 --format="format:%s")
+		if [[ "$fixes_subject" != "(\"$orig_subject\")" ]] ; then
+			echoerr "$cite: Subject in fixes line doesn't match referenced commit:"
+			echoerr "    $fline"
+			rv=1
+			continue
+		fi
+
+	done ; exit $rv )
+
+	rv=$?
+
+	return $rv
+}
+
 # additional patch checks before pushing, e.g. for r-b tags
 function checkpatch_commit_push
 {
@@ -844,6 +904,10 @@ function checkpatch_commit_push
 		rv=1
 	fi
 
+	if ! checkpatch_fixes_tag $sha1 ; then
+		rv=1
+	fi
+
 	return $rv
 }
 
-- 
2.20.1