Patchwork D6711: branchheads: store wdir-dependent caches in wcache (issue6181)

diff --git a/tests/test-branchmap-cache.t b/tests/test-branchmap-cache.t
new file mode 100644
--- /dev/null
+++ b/tests/test-branchmap-cache.t
@@ -0,0 +1,38 @@ 
+  $ cat >> $HGRCPATH << EOF
+  > [extensions]
+  > share=
+  > [experimental]
+  > evolution=createmarkers
+  > EOF
+  $ hg init -q orig
+  $ cd orig
+  $ echo hi > foo
+  $ hg ci -qAm initial_rev0
+  $ echo "hi again" >> foo
+  $ hg ci -qAm "hi again rev1"
+  $ hg commit -q --amend -m "obsoleted 1, this is rev2"
+  $ cd ..
+  $ hg share -q orig other
+  $ cd other
+  $ hg co -qr 1 --hidden
+  updated to hidden changeset a3571a6d8234
+  (hidden revision 'a3571a6d8234' was rewritten as: 0444ce380f11)
+  $ cd ..
+
+Forcefully update the caches in each repo once; we're not using --debug since we
+know that these are going to update some/all of the caches, we don't need to
+know which.
+  $ hg -R orig debugupdatecache
+  $ hg -R other debugupdatecache
+
+The branchheads caches should not change just because we're accessing from a
+different repo each time. If they were stale, we'd get another line in the
+output per filtername that's stale.
+  $ hg -R orig debugupdatecache --debug
+  updating the branch cache
+  $ hg -R other debugupdatecache --debug
+  updating the branch cache
+  $ hg -R orig debugupdatecache --debug
+  updating the branch cache
+  $ hg -R other debugupdatecache --debug
+  updating the branch cache
diff --git a/mercurial/utils/repoviewutil.py b/mercurial/utils/repoviewutil.py
--- a/mercurial/utils/repoviewutil.py
+++ b/mercurial/utils/repoviewutil.py
@@ -26,3 +26,8 @@ 
 # can be calculated from `subsettable` but `subsettable` is essentially
 # constant, so we just hard-code it.
 subsettableheads = frozenset({'visible-hidden', 'served.hidden'})
+
+# List of views that are potentially dependent upon wdir state (such as the
+# current parents of the working directory) and need to be kept in wcache
+# instead of cache.
+wdirdependent = frozenset(['served', 'visible', 'visible-hidden'])
diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
--- a/mercurial/branchmap.py
+++ b/mercurial/branchmap.py
@@ -221,7 +221,7 @@ 
     def fromfile(cls, repo):
         f = None
         try:
-            f = repo.cachevfs(cls._filename(repo))
+            f = cls._opencachefile(repo)
             lineiter = iter(f)
             cachekey = next(lineiter).rstrip('\n').split(" ", 2)
             last, lrev = cachekey[:2]
@@ -271,12 +271,15 @@ 
                 self._closednodes.add(node)
 
     @staticmethod
-    def _filename(repo):
+    def _opencachefile(repo, *args, **kwargs):
         """name of a branchcache file for a given repo or repoview"""
         filename = "branch2"
+        vfs = repo.cachevfs
         if repo.filtername:
             filename = '%s-%s' % (filename, repo.filtername)
-        return filename
+            if repo.filtername in repoviewutil.wdirdependent:
+                vfs = repo.wcachevfs
+        return vfs(filename, *args, **kwargs)
 
     def validfor(self, repo):
         """Is the cache content valid regarding a repo
@@ -335,7 +338,7 @@ 
 
     def write(self, repo):
         try:
-            f = repo.cachevfs(self._filename(repo), "w", atomictemp=True)
+            f = self._opencachefile(repo, "w", atomictemp=True)
             cachekey = [hex(self.tipnode), '%d' % self.tiprev]
             if self.filteredhash is not None:
                 cachekey.append(hex(self.filteredhash))