SCRIPTS: git-show-backports: add -H to use the hash of the commit message

Sometimes certain commits don't contain useful tracking information but
we'd still like to be able to report them. Here we implement a hash on
the author's name, e-mail and date, the subject and the body before the
first s-o-b or cherry-picked line. These parts are supposed to be
reasonable invariant across backports and are usable to compute an
invariant hash of a given commit. When we don't find ancestry in a
commit, we try this method (if -H is specified) to compare commits
hashes and we can report a match. The equivalent commit is reported
as "XXXX+?" to indicate that it's an apparent backport but we don't
know how far it goes.

diff --git a/scripts/git-show-backports b/scripts/git-show-backports
index ca7ad4f76c352bf2ccab375e6a43560005cd508c..15697016af10d21e387693e89ba1aa753a521317 100755 (executable)
--- a/scripts/git-show-backports
+++ b/scripts/git-show-backports
@@ -28,7 +28,7 @@
 #   show-backports -q -m -r hapee-r2 hapee-r1
 
 
-USAGE="Usage: ${0##*/} [-q] [-m] [-u] [-r reference] [-l logexpr] [-s subject] [-b base] {branch|range} [...]"
+USAGE="Usage: ${0##*/} [-q] [-H] [-m] [-u] [-r reference] [-l logexpr] [-s subject] [-b base] {branch|range} [...]"
 BASES=( )
 BRANCHES=( )
 REF=master
@@ -38,6 +38,7 @@ LOGEXPR=
 SUBJECT=
 MISSING=
 UPSTREAM=
+BODYHASH=
 
 die() {
        [ "$#" -eq 0 ] || echo "$*" >&2
@@ -75,10 +76,12 @@ dump_commit_matrix() {
 
                upstream="none"
                missing=0
+               refbhash=""
                line=""
                for branch in "${BRANCHES[@]}"; do
                        set -- $(grep -m 1 $ref "$WORK/${branch//\//_}")
                        newhash=$1 ; shift
+                       bhash=""
                        # count the number of cherry-picks after this one. Since we shift,
                        # the result is in "$#"
                        while [ -n "$1" -a "$1" != "$ref" ]; do
@@ -108,6 +111,19 @@ dump_commit_matrix() {
                                                break
                                        fi
                                done
+                               if [ -z "$newhash" -a -n "$BODYHASH" ]; then
+                                       if [ -z "$refbhash" ]; then
+                                               refbhash=$(git log -1 --pretty="%an|%ae|%at|%B" "$ref" | sed -n '/^\(Signed-off-by\|(cherry picked\)/q;p' | md5sum)
+                                       fi
+
+
+                                       set -- $(grep -m 1 "H$refbhash\$" "$WORK/${branch//\//_}")
+                                       newhash=$1 ; shift
+                                       if [ -n "$newhash" ]; then
+                                               line="${line} $(short $newhash)+?"
+                                               break
+                                       fi
+                               fi
                                if [ -z "$newhash" ]; then
                                        line="${line} -"
                                        missing=1
@@ -136,6 +152,7 @@ while [ -n "$1" -a -z "${1##-*}" ]; do
                -q)        QUIET=1        ; shift   ;;
                -m)        MISSING=1      ; shift   ;;
                -u)        UPSTREAM=1     ; shift   ;;
+               -H)        BODYHASH=1     ; shift   ;;
                -h|--help) quit "$USAGE" ;;
                *)         die  "$USAGE" ;;
        esac
@@ -194,8 +211,13 @@ while [ $branch_num -lt "${#BRANCHES[@]}" ]; do
        base="${base:-$BASE}"
        rm -f "$WORK/${branch//\//_}"
        git log --reverse --pretty="%H %s" "$base".."$branch" | grep "${SUBJECT}" | while read h subject; do
-               echo "$h" $(git log -1 --pretty --format=%B "$h" | \
+               echo -n "$h" $(git log -1 --pretty --format=%B "$h" | \
                        sed -n 's/^commit \([^)]*\) upstream\.$/\1/p;s/^(cherry picked from commit \([^)]*\))/\1/p')
+               if [ -n "$BODYHASH" ]; then
+                       echo " H$(git log -1 --pretty="%an|%ae|%at|%B" "$h" | sed -n '/^\(Signed-off-by\|(cherry picked\)/q;p' | md5sum)"
+               else
+                       echo
+               fi
        done > "$WORK/${branch//\//_}"
        (( branch_num++ ))
 done