A watchlist is a mechanism that allows a developer (a “watcher”) to watch over portions of code that the watcher is interested in. A watcher will be cc-ed on changes that modify that portion of code, thereby giving that watcher an opportunity to make comments on chromium-review.googlesource.com even before the change is committed.
Watchlists are defined using aWATCHLISTS file, which resides at the root of a repository. A typicalWATCHLISTS file looks like:
{ 'WATCHLIST_DEFINITIONS': { 'valgrind': { 'filepath': 'tools/valgrind/', }, 'mac': { 'filepath': 'cocoa|\.mm$|(_mac|_posix)\.(cc|h)$', }, }, 'WATCHLISTS': { 'valgrind': ['nirnimesh@chromium.org', 'dank@chromium.org'], },}In this case, watchlists namedvalgrind andmac are defined inWATCHLIST_DEFINITIONS and their corresponding watchers declared inWATCHLISTS.
In the example above, whenever a new changeset is created that refers to any file intools/valgrind/, the'valgrind' watchlist will be triggered andnirnimesh@chromium.org &dank@chromium.org will be cc-ed to the changeset for review. A regular expression can be used as the matching pattern. Matches are determined using python'sre.search() function call, so matchingA_WORD is the same as matching.*A_WORD.*.
Each name inWATCHLISTS must be defined first inWATCHLIST_DEFINITIONS.
Watchlist processing takes place on Gerrit with the “Watchlists” analyzer and is non-binding; that is, an approval from that watcher is not needed for commit. It merely gives the watcher an opportunity to make comments, if any.
You create new watchlists or add yourself to existing watchlists by editing the WATCHLISTS file at the base of the repository.
It's advisable to runwatchlists.py to verify that your new rules work.
Example (from src):
python third_party/depot_tools/watchlists.py PATH/TO/FILE1 PATH/TO/FILE2 ....