When a watch is executed currently, it gets passed an in-memory
watch object, that was loaded, before the execution started.
This means there is a window of time, where an old watch could still
be executing, then a watch gets loaded for execution, then the old watch
execution finishes and updates the watch status and thus reindexes the
watch.
Now the watch, that got loaded for execution, executes and tries to
store its watch status, but fails, because the version of the watch
has changed.
This commit changes the point in time where the watch is loaded. Now
this only happens, while a watch is in its protected execution block,
and thus we can be sure, that there is no other execution of the watch
happening.
This will primarily impact watches, that execute often, but their
runtime is longer than the configured interval between executions.
Side fix: Removed some duplicate testing method and moved into
WatcherTestUtils, fixed a tests with a ton of if's with random booleans
into separate tests.
relates elastic/x-pack-elasticsearch#395
Original commit: elastic/x-pack-elasticsearch@bf393023d7
1b6d9d430c