commit 7ecae33e24723964b354a829fde21131477a58db
author Shawn Pearce <sop@google.com> Wed Aug 02 08:40:51 2017 -0700
committer Alice Kober-Sotzek <aliceks@google.com> Mon Sep 25 15:50:12 2017 +0200
tree 4485f910b57fd52169889f280de582f20cca56f9
parent ab7b0a8f0cdcfaa065c3643417d5a28d75b0862a

Index files affected by merge commits

This commit has the effect of changing ChangeData.currentFilePaths()
to return the diff of a merge commit to be between the merge commit's
new tree, and its 1st parent. That allows ChangeField.PATH to index
the files affected by a merge commit, which supports the conflicts
operator to identify open merges that may conflict with a change.

The only caller of PatchListCache.getDiffSummary() is
ChangeData.currentFilePaths().  The only caller of
ChangeData.currentFilePaths() is ChangeField.PATH (for indexing)
and query operators that test against a change.

A side-effect of this commit is the changed lines (added, deleted,
delta) for merge commits will now report the delta introduced by the
merge, rather than the delta from the automerge.

The conflicts operator now detects a few less cases of conflicts.  The
most obvious change is a merge uploaded to the wrong branch may not
show a conflict with other changes on its current branch when its 1st
parent (from the other branch) introduces a conflicting change.

The conflicts operator now assumes merges are made "correctly", such
that `git log --first-parent` will traverse the main-branch history,
and not the side-branch. This requires users to do something like:

  git checkout -b my-merge origin/master
  git merge side-branch
  git push origin my-merge:refs/for/master

When creating a merge commit to merge "side-branch" into "master".
Since this is a typical workflow with git, most merges should already
fit this expected pattern.

A new change index schema version 46 is required to ensure changes are
reindexed with this new computation for the PATH field.

Bug: issue 3052
Change-Id: Iaa854447ed9abb77b3f8fe6c818723e804e0a8d4