commit 484da493b3a4585bae3dd68e4de4fc2166dbcd12
author Dave Borowitz <dborowitz@google.com> Fri Jan 13 16:26:45 2017 -0500
committer David Pursehouse <dpursehouse@collab.net> Wed Jan 18 10:36:38 2017 +0900
tree fd6ae006ef0ec4f952c55934b51f47e4a2625d99
parent e5c595320511ecb905aa546bb707991d756292c5

Prefer subtypes of Multimap

Guava team recommends using the subinterfaces of Multimap, for the
same reasons they recommend using Set and List rather than Collection:
it documents expectations about ordering, uniqueness, and behavior of
equals. Do this across the board in Gerrit.

Mostly this is straightforward and I tried to exactly match existing
behavior where possible. However, there were a few wrinkles, where
different callers passed different subtypes to the same method.

The main one is arguments to ParameterParser#parse and
splitQueryString, where some callers used SetMultimaps (perhaps
semi-intentionally, or perhaps misunderstanding the nature of
HashMultimap). For the purposes of parameter parsing, a ListMultimap
makes more sense, because it preserves argument order and repetition.

Another instance is a couple places in ReceiveCommits and downstream
where there were SetMultimap<?, Ref>. Since Refs do not implement
equals, this is effectively the same thing as a ListMultimap, and
changing the interface no longer misleads readers into thinking there
might be some deduplication happening.

Finally, this change includes a breaking API change to the return
type of ExternalIncludedIn#getIncludedIn.

Change-Id: I5f1d15e27a32e534a6aaefe204e7a31815f4c8d7