D5636: branchmap: updating triggers a write

[mjpieters (Martijn Pieters)]

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

REVISION SUMMARY
  Rather than separate updating and writing, create a subclass that doesn't write
  on update. This minimises chances we forget to write out updates somewhere.
  
  This also makes refactoring and improving the branchmap functionality easier.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5636

AFFECTED FILES
  mercurial/branchmap.py
  mercurial/discovery.py

CHANGE DETAILS

diff --git a/mercurial/discovery.py b/mercurial/discovery.py
--- a/mercurial/discovery.py
+++ b/mercurial/discovery.py
@@ -238,7 +238,7 @@
 
     # D. Update newmap with outgoing changes.
     # This will possibly add new heads and remove existing ones.
-    newmap = branchmap.branchcache((branch, heads[1])
+    newmap = branchmap.remotebranchcache((branch, heads[1])
                                  for branch, heads in headssum.iteritems()
                                  if heads[0] is not None)
     newmap.update(repo, (ctx.rev() for ctx in missingctx))
diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
--- a/mercurial/branchmap.py
+++ b/mercurial/branchmap.py
@@ -63,7 +63,6 @@
     revs.extend(cl.revs(start=bcache.tiprev + 1))
     if revs:
         bcache.update(repo, revs)
-        bcache.write(repo)
 
     assert bcache.validfor(repo), filtername
     repo._branchcaches[repo.filtername] = bcache
@@ -242,8 +241,9 @@
 
     def copy(self):
         """return an deep copy of the branchcache object"""
-        return branchcache(self, self.tipnode, self.tiprev, self.filteredhash,
-                           self._closednodes)
+        return type(self)(
+            self, self.tipnode, self.tiprev, self.filteredhash,
+            self._closednodes)
 
     def write(self, repo):
         try:
@@ -332,6 +332,15 @@
         repo.ui.log('branchcache', 'updated %s branch cache in %.4f seconds\n',
                     repo.filtername, duration)
 
+        self.write(repo)
+
+
+class remotebranchcache(branchcache):
+    """Branchmap info for a remote connection, should not write locally"""
+    def write(self, repo):
+        pass
+
+
 # Revision branch info cache
 
 _rbcversion = '-v1'



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