py3: change default priority and length used for sorting hooks to be compatible with python 3 The call to `sorted(hooks.values())` can on line 213 of hooks.py can raise when using python 3. For instance, when hooks.values is `[(0, 2, b'post-commit.check-status', b''), (None, None, b'changegroup.app-hooks', <object object at 0x7f5279885590>)]`, the error is `TypeError: '<' not supported between instances of 'NoneType' and 'int'` This fix keeps the same order that was used in python 2 without relying on comparison with None. Differential Revision: https://phab.mercurial-scm.org/D8527

relnotes: copy "next" to "5.4" and clear "next" This is the same thing as we've done for the previous few releases. Differential Revision: https://phab.mercurial-scm.org/D8546

dirstate: make sure the dirstate is loaded before the changelog (issue6303) Before this change, it was possible for the changelog to be loaded before the dirstate. If a transaction happens betwen the changelog and dirstate reading, the dirstate can up end poitning toward a revision not existing in the (olded) changelog. This lead to a warning. With this revision, we preload the dirstate parent before reading the changelog. This has a negligible performance impact on performance for all case we are tracking. Differential Revision: https://phab.mercurial-scm.org/D8528