Improve the backport script.

It now uses the origin/master branch rather than the master branch, thus
avoiding the need for local merges.

More importantly, it no longer creates a subshell in case of conflicts,
but instead gives control back to the user. Once conflicts are solved, it
suffices to relaunch the script (instead of exiting the subshell). The
reason is that, otherwise, there was no sane way of giving up a backport,
due to the infinite subshell loop.

1 files changed, 18 insertions, 12 deletions

diff --git a/dev/tools/backport-pr.sh b/dev/tools/backport-pr.sh
index 9864fd4d69..1ec8251f66 100755
--- a/dev/tools/backport-pr.sh
+++ b/dev/tools/backport-pr.sh
@@ -30,13 +30,15 @@ while [[ $# -gt 0 ]]; do
     esac
 done
 
-if ! git log master --grep "Merge PR #${PRNUM}" | grep "." > /dev/null; then
+MASTER=origin/master
+
+if ! git log $MASTER --grep "Merge PR #$PRNUM" | grep "." > /dev/null; then
     echo "PR #${PRNUM} does not exist."
     exit 1
 fi
 
-SIGNATURE_STATUS=$(git log master --grep "Merge PR #${PRNUM}" --format="%G?")
-git log master --grep "Merge PR #${PRNUM}" --format="%GG"
+SIGNATURE_STATUS=$(git log $MASTER --grep "Merge PR #$PRNUM" --format="%G?")
+git log $MASTER --grep "Merge PR #$PRNUM" --format="%GG"
 if [[ "$NO_SIGNATURE_CHECK" != "true" && "$SIGNATURE_STATUS" != "G" ]]; then
     echo
     read -p "Merge commit does not have a good (valid) signature. Bypass? [y/N] " -n 1 -r
@@ -47,10 +49,18 @@ if [[ "$NO_SIGNATURE_CHECK" != "true" && "$SIGNATURE_STATUS" != "G" ]]; then
 fi
 
 BRANCH=backport-pr-${PRNUM}
-RANGE=$(git log master --grep "Merge PR #${PRNUM}" --format="%P" | sed 's/ /../')
-MESSAGE=$(git log master --grep "Merge PR #${PRNUM}" --format="%s" | sed 's/Merge/Backport/')
+RANGE=$(git log $MASTER --grep "Merge PR #$PRNUM" --format="%P" | sed 's/ /../')
+MESSAGE=$(git log $MASTER --grep "Merge PR #$PRNUM" --format="%s" | sed 's/Merge/Backport/')
 
-if git checkout -b "${BRANCH}"; then
+if [[ "$(git rev-parse --abbrev-ref HEAD)" == "$BRANCH" ]]; then
+
+    if ! git cherry-pick --continue; then
+        echo "Please fix the conflicts, then relaunch the script."
+        exit 1
+    fi
+    git checkout -
+
+elif git checkout -b "$BRANCH"; then
 
     if ! git cherry-pick -x "${RANGE}"; then
         if [[ "$NO_CONFLICTS" == "true" ]]; then
@@ -61,12 +71,8 @@ if git checkout -b "${BRANCH}"; then
             git branch -d "$BRANCH"
             exit 1
         fi
-        echo "Please fix the conflicts, then exit."
-        bash
-        while ! git cherry-pick --continue; do
-            echo "Please fix the conflicts, then exit."
-            bash
-        done
+        echo "Please fix the conflicts, then relaunch the script."
+        exit 1
     fi
     git checkout -