help: add a missing blank line to unhide `revlog-compression` The help was output, but it was elided with "Enabled by default" from the previous item.

copies: avoid reusing the same variable for two different copy dicts "childcopies" is initally the copies the current changeset to one of its children and then we reassign it with the copies from the start of the chain to the child. Let's use different names for these two things. Differential Revision: https://phab.mercurial-scm.org/D6564

drawdag: don't crash when writing copy info to changesets When writing copies to the changeset, localrepo.commitctx() will call ctx.p1copies() and ctx.p2copies(). These crashed on simplecommitctx because they ended up trying to access the manifest. drawdag doesn't support copies at all, so we can simply override the methods to return empty dicts. Differential Revision: https://phab.mercurial-scm.org/D6565

merge with stable

bookmarks: actual fix for race condition deleting bookmark This is a simple but efficient fix to prevent the issue tested in `test-bookmarks-corner-case.t`. It might be worth pursuing a more generic approach where filecache learn to depend on each other, but that would not be suitable for stable. The issue is complicated enough that I documented the race and its current solution as inline comment. See this comment for details on the fix.

localrepo: introduce a `_refreshchangelog` method See next changeset for usage and documentation for details.

bookmarks: actually trigger the race deleting bookmark in the test The previous committed version of the test did not triggered the race, but this was hidden by a strange behavior from the test runner. So we are moving the test to a slightly more complex that actually trigger the issue.

test: add some assert in the bookrace extension This cannot hurt to have a bit more security in the test extension.

test: factor out the "wait" logic in bookrace The test is currently not testing the race it is supposed to test. The synchronisation is still valid, but needs to run at a different point. We start with extracting the synchronisation logic for clarity.

test: remove dead code in the bookrace extension This code is the remain of a previous version of the code. It is never ran, so we can remove it.