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

rust-dirstatemap: don't read the dirstate when requesting parents A future patch for issue 6303 reveals a big performance regression in the Rust `DirstateMap` that reads the entire dirstate when requesting parents instead of the first 40 bytes. `perfdiscovery` gets a *significant* speedup (from 0.101 to 0.016) when applied against said patch. I'm assuming it has other performance benefits, but this is already a good enough win. Differential Revision: https://phab.mercurial-scm.org/D8513