obsutil: sort metadata before comparing in geteffectflag() This is probably less important now that we dropped Python 2. We do still support Python 3.6 though, and the dictionaries aren't ordered there either (that was a big change that came with 3.7). Still, maybe it's a good idea to sort metadata explicitly.

tests: disable revlog compression in test-generaldelta.t (issue6867) The revlog compression makes a lot of numbers unstable. Since checking revlog compression is not the goal of this test, we disable the compression to get stable numbers. This should avoid wasting more time on this kind of changes in the future.

test-general-delta: actually test optimize-delta-parent-choice=no Since the configuration was not explicit, the case stopped testing what it intended to test when the default value changed.

test-chg: stabilize the log checking The "worker process exited" line have been making the CI flaky for a long time. Lets sort this out.

tests: fix test-patchbomb-tls.t instability The flakiness on chg is caused by a client that exit faster than the server output log. So actively wait for the server to issue the expected output (with a small timeout)

test-lock: use synchronisation file instead of sleep This will prevent the test to be flaky on load.

branchcache: use update_disk to refresh 'served' and 'served.hidden' The `update_disk` method is dedicated to this kind of usecase. Now that the writting patterns are more consistent, we can use it to warm these two important cache. I am dropping the first comment about "refreshing all the others" because it is false. If a branchmap already exist for "served", none of the subset will be updated.

branchcache: explictly update disk state only if no transaction exist If a transaction exist the `write_dirty` call will eventually be done and the state will be synched on disk. It is better to no interfer with that.

branchcache: do not use `__getitem__` in updatecache The `update_disk` method uses `updatecache` and the point of `update_disk` is to be able to do alternative processing to the one we do in `__getitem__`. So we calling `__getitem__` in `updatecache` defeat this purpose. Instead we do the equivalent explicitly to preserve the spirit of `update_disk` (that we will actually put to use soon, I promise)

branchcache: explicitly track inheritence "state" We move from a binary "dirty" flag to a three value "state": "clean", "inherited", "dirty". The "inherited" means that the branch cache is not only "clean", but it is a duplicate of its parent filter. If a branch cache is "inherited", we can non only skip writing its value on disk, but it is a good idea to delete any stale value on disk, as those will just waste time (and possibly induce bug) in the future. We only do this in the update related to transaction or explicit cache update (e.g `hg debugupdatecache`). Deleting the file when we simply detected a stall cache during a read only operation seems more dangerous. We rename `copy` to `inherit_for` to clarify we associate a stronger semantic to the operation.