diff mercurial/localrepo.py @ 44826:35b255e474d9 stable

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

--- a/mercurial/localrepo.py	Mon May 11 16:44:11 2020 +0200
+++ b/mercurial/localrepo.py	Mon May 11 13:08:02 2020 +0200
@@ -1450,6 +1450,8 @@
 
     @storecache(b'00changelog.i')
     def changelog(self):
+        # load dirstate before changelog to avoid race see issue6303
+        self.dirstate.prefetch_parents()
         return self.store.changelog(txnutil.mayhavepending(self.root))
 
     @storecache(b'00manifest.i')