D7854: phases: make phasecache._phasesets immutable

[rdamazio (Rodrigo Damazio Bovendorp)]

rdamazio created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

REVISION SUMMARY
  Previously, some code paths would mutate the cache itself, which
  could give weird results if multiple revsets got evaluated through
  that path.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D7854

AFFECTED FILES
  mercurial/phases.py

CHANGE DETAILS

diff --git a/mercurial/phases.py b/mercurial/phases.py
--- a/mercurial/phases.py
+++ b/mercurial/phases.py
@@ -253,15 +253,19 @@
 
         # fast path: _phasesets contains the interesting sets,
         # might only need a union and post-filtering.
+        revsneedscopy = False
         if len(phases) == 1:
             [p] = phases
             revs = self._phasesets[p]
+            revsneedscopy = True  # Don't modify _phasesets
         else:
             # revs has the revisions in all *other* phases.
             revs = set.union(*[self._phasesets[p] for p in phases])
 
         def _addwdir(wdirsubset, wdirrevs):
             if wdirrev in wdirsubset and repo[None].phase() in phases:
+                if revsneedscopy:
+                    wdirrevs = wdirrevs.copy()
                 # The working dir would never be in the # cache, but it was in
                 # the subset being filtered for its phase (or filtered out,
                 # depending on publicphase), so add it to the output to be



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Cc: mercurial-devel