build_no_op_commits.sh

#!/bin/bash

function show_error_msg()

  echo "*** ERROR *** $? line $1 $0 did not complete successfully!"

  echo "$ERROR_HELP"

ERROR_HELP=""

# Print an Error message if `set -eE` causes the script to exit due to a failed command

trap 'show_error_msg $LINENO' ERR

source dom/media/webrtc/third_party_build/use_config_env.sh

echo "MOZ_LIBWEBRTC_SRC: $MOZ_LIBWEBRTC_SRC"

# After this point:

# * eE: All commands should succeed.

# * u: All variables should be defined before use.

# * o pipefail: All stages of all pipes should succeed.

set -eEuo pipefail

CURRENT_DIR=`pwd`

cd $MOZ_LIBWEBRTC_SRC

MANUAL_INTERVENTION_COMMIT_FILE="$TMP_DIR/manual_commits.txt"

rm -f $MANUAL_INTERVENTION_COMMIT_FILE

# Find the common commit between our previous work branch and trunk

CURRENT_RELEASE_BASE=`git merge-base branch-heads/$MOZ_PRIOR_UPSTREAM_BRANCH_HEAD_NUM master`

# Write no-op files for the cherry-picked release branch commits.  For more

# details on what this is doing, see make_upstream_revert_noop.sh.

COMMIT_RANGE="$CURRENT_RELEASE_BASE..branch-heads/$MOZ_PRIOR_UPSTREAM_BRANCH_HEAD_NUM"

echo ""

echo "Libwebrtc release branch commits are usually cherry-picked from upcoming"

echo "commits.  Since these upcoming commits will result in near-zero files"

echo "changed, hopefully exactly 0, we need to build no-op commit files"

echo "so that processing doesn't stop unnecessarily when running the"

echo "fast-forward process."

echo "Previous update (Bug $MOZ_PRIOR_FASTFORWARD_BUG) release branch commits:"

# might be nice to indent this output for better readability

git log $COMMIT_RANGE --oneline

COMMITS=`git log -r $COMMIT_RANGE --format='%h'`

for commit in $COMMITS; do

  echo "Processing release branch commit $commit for no-op handling"

  # Don't process the commit if the commit message is missing the customary

  # line that shows which upstream commit is being cherry-picked.

  CNT=`git show $commit | grep "cherry picked from commit" | wc -l | tr -d " " || true`

  if [ $CNT != 1 ]; then

    # record the commit to list at the end of this script as

    # 'needing intervention'

    echo "    no cherry-pick info found, skipping commit $commit"

    echo "$commit" >> $MANUAL_INTERVENTION_COMMIT_FILE

    continue

fi

  CHERRY_PICK_COMMIT=`git show $commit | grep "cherry picked from commit" | tr -d "()" | awk '{ print $5; }'`

  SHORT_SHA=`git show --name-only $CHERRY_PICK_COMMIT --format='%h' | head -1`

  echo "    commit $commit cherry-picks $SHORT_SHA"

  echo "We already cherry-picked this when we vendored $commit." \

  > $STATE_DIR/$SHORT_SHA.no-op-cherry-pick-msg

done

# This section checks for commits that may have been cherry-picked in more

# than one release branch.

TARGET_RELEASE_BASE=`git merge-base $MOZ_TARGET_UPSTREAM_BRANCH_HEAD master`

COMMIT_RANGE="$TARGET_RELEASE_BASE..$MOZ_TARGET_UPSTREAM_BRANCH_HEAD"

echo ""

echo "Occasionally, successive libwebrtc release branches need to cherry-pick"

echo "the same _far_ upstream commit.  We need to examine the upcoming release"

echo "branch commits for our new v$MOZ_NEXT_LIBWEBRTC_MILESTONE update."

echo "Upcoming (Bug $MOZ_FASTFORWARD_BUG) release branch commits:"

# might be nice to indent this output for better readability

git log $COMMIT_RANGE --oneline

# Convert the files that we've already generated for no-op detection into

# something that we can use as a regular expression for searching.

KNOWN_NO_OP_COMMITS=`cd $STATE_DIR ; \

  ls *.no-op-cherry-pick-msg \

  | sed 's/\.no-op-cherry-pick-msg//' \

  | paste -sd '|' /dev/stdin`

NEW_COMMITS=`git log -r $COMMIT_RANGE --format='%h'`

for commit in $NEW_COMMITS; do

  echo "Processing next release branch commit $commit for no-op handling"

  # Don't process the commit if the commit message is missing the customary

  # line that shows which upstream commit is being cherry-picked.

  CNT=`git show $commit | grep "cherry picked from commit" | wc -l | tr -d " " || true`

  if [ $CNT != 1 ]; then

    # record the commit to list at the end of this script as

    # 'needing intervention'

    echo "    no cherry-pick info found, skipping commit $commit"

    echo "$commit" >> $MANUAL_INTERVENTION_COMMIT_FILE

    continue

fi

  CHERRY_PICK_COMMIT=`git show $commit | grep "cherry picked from commit" | tr -d "()" | awk '{ print $5; }'`

  SHORT_SHA=`git show --name-only $CHERRY_PICK_COMMIT --format='%h' | head -1`

  # The trick here is that we only want to include no-op processing for the

  # commits that appear both here _and_ in the previous release's cherry-pick

  # commits.  We check the known list of no-op commits to see if it was

  # cherry picked in the previous release branch and then create another

  # file for the new release branch commit that will ultimately be a no-op.

  if [[ "$SHORT_SHA" =~ ^($KNOWN_NO_OP_COMMITS)$ ]]; then

    echo "    commit $commit cherry-picks $SHORT_SHA"

    cp $STATE_DIR/$SHORT_SHA.no-op-cherry-pick-msg $STATE_DIR/$commit.no-op-cherry-pick-msg

fi

done

if [ ! -f $MANUAL_INTERVENTION_COMMIT_FILE ]; then

  echo "No commits require manual intervention"

  exit

fi

echo $"

Each of the following commits requires manual intervention to

verify the source of the cherry-pick or there may be errors

reported during the fast-forward processing.  Without this

intervention, the common symptom is that the vendored commit

file count (0) will not match the upstream commit file count.

for commit in `cat $MANUAL_INTERVENTION_COMMIT_FILE`; do

  SUMMARY=`git show --oneline --name-only $commit | head -1`

  echo "  '$SUMMARY'"

done

echo $"

To manually create the no-op tracking files needed,

run the following command (in bash) for each commit in question:

  ( export FUTURE_UPSTREAM_COMMIT=\"{short-sha-of-upstream-commit}\" ; \\

    export ALREADY_USED_COMMIT=\"{short-sha-of-already-used-commit}\" ; \\

    echo \"We already cherry-picked this when we vendored \$ALREADY_USED_COMMIT.\" \\

    > $STATE_DIR/\$FUTURE_UPSTREAM_COMMIT.no-op-cherry-pick-msg )