destroyed: drop complex branchcache rebuilt logic

The strip code used a trick to lower the cost of branchcache update after a
strip. However is less necessary since we have branchcache collaboration.
Invalid branchcache are likely to be cheaply rebuilt again a near subset of the
repo.

Moreover, this trick would need update to be relevant in the now filtered
repository world. It currently update the unfiltered branchcache that few people
cares about. Make it smarter on that aspect would need complexes update of the
calling logic


So this mechanism is:
- Arguably needed,
- Currently irrelevant,
- Hard to update
and I'm dropping it.

We now update the branchcache in all case by courtesy of the read only reader.

This changeset have a few expected impact on the testsuite are different cache
are updated.

mercurial/localrepo.py

@@ -1398,7 +1398,7 b' class localrepository(object):'
             self._phasecache.write()
 
     @unfilteredmethod
-    def destroyed(self, newheadnodes=None):
+    def destroyed(self):
         '''Inform the repository that nodes have been destroyed.
         Intended for use by strip and rollback, so there's a common
         place for anything that has to be done after destroying history.
@@ -1421,16 +1421,9 b' class localrepository(object):'
             self._phasecache.filterunknown(self)
             self._phasecache.write()
 
-        # If we have info, newheadnodes, on how to update the branch cache, do
-        # it, Otherwise, since nodes were destroyed, the cache is stale and this
-        # will be caught the next time it is read.
-        if newheadnodes:
-            cl = self.changelog
-            revgen = (cl.rev(node) for node in newheadnodes
-                      if cl.hasnode(node))
-            cache = self._branchcaches[None]
-            cache.update(self, revgen)
-            cache.write(self)
+        # update branchcache information likely invalidated by the strip.
+        # We rely on branchcache collaboration for this call to be fast
+        branchmap.updatecache(self)
 
         # Ensure the persistent tag cache is updated.  Doing it now
         # means that the tag cache only has to worry about destroyed

mercurial/repair.py

@@ -66,17 +66,6 b' def strip(ui, repo, nodelist, backup="al'
     striplist = [cl.rev(node) for node in nodelist]
     striprev = min(striplist)
 
-    # Generate set of branches who will have nodes stripped.
-    striprevs = repo.revs("%ld::", striplist)
-    stripbranches = set([repo[rev].branch() for rev in striprevs])
-
-    # Set of potential new heads resulting from the strip.  The parents of any
-    # node removed could be a new head because the node to be removed could have
-    # been the only child of the parent.
-    newheadrevs = repo.revs("parents(%ld::) - %ld::", striprevs, striprevs)
-    newheadnodes = set([cl.node(rev) for rev in newheadrevs])
-    newheadbranches = set([repo[rev].branch() for rev in newheadrevs])
-
     keeppartialbundle = backup == 'strip'
 
     # Some revisions with rev > striprev may not be descendants of striprev.
@@ -191,10 +180,4 b' def strip(ui, repo, nodelist, backup="al'
                     % chgrpfile)
         raise
 
-    if len(stripbranches) == 1 and len(newheadbranches) == 1 \
-            and stripbranches == newheadbranches:
-        repo.destroyed(newheadnodes)
-    else:
-        # Multiple branches involved in strip. Will allow branchcache to become
-        # invalid and later on rebuilt from scratch
         repo.destroyed()

tests/test-acl.t

@@ -1527,7 +1527,6 b' Branch acl deny test'
   query 1; heads
   searching for changes
   all remote heads known locally
-  invalid branchheads cache (served): tip differs
   listing keys for "bookmarks"
   4 changesets found
   list of changesets:
@@ -1839,7 +1838,6 b' push foobar into the remote'
   query 1; heads
   searching for changes
   all remote heads known locally
-  invalid branchheads cache (served): tip differs
   listing keys for "bookmarks"
   4 changesets found
   list of changesets:
@@ -1927,7 +1925,6 b' Branch acl conflicting deny'
   query 1; heads
   searching for changes
   all remote heads known locally
-  invalid branchheads cache (served): tip differs
   listing keys for "bookmarks"
   4 changesets found
   list of changesets:
@@ -2083,7 +2080,6 b' Non-astro users must be denied'
   query 1; heads
   searching for changes
   all remote heads known locally
-  invalid branchheads cache (served): tip differs
   listing keys for "bookmarks"
   4 changesets found
   list of changesets:

tests/test-keyword.t

@@ -507,6 +507,7 b' amend'
   $ hg -q commit -d '14 1' -m 'prepare amend'
 
   $ hg --debug commit --amend -d '15 1' -m 'amend without changes' | grep keywords
+  invalid branchheads cache (served): tip differs
   overwriting a expanding keywords
   $ hg -q id
   67d8c481a6be

tests/test-mq-symlinks.t

@@ -45,7 +45,6 b' test updating a symlink'
   popping updatelink
   now at: symlink.patch
   $ hg qpush --debug
-  invalid branchheads cache (served): tip differs
   applying updatelink
   patching file a
   a

tests/test-rebase-collapse.t

@@ -263,9 +263,10 b' Rebase and collapse - E onto H:'
 
 
 Test that branchheads cache is updated correctly when doing a strip in which
-the parent of the ancestor node to be stripped does not become a head and
-also, the parent of a node that is a child of the node stripped becomes a head
-(node 3).
+the parent of the ancestor node to be stripped does not become a head and also,
+the parent of a node that is a child of the node stripped becomes a head (node
+3). The code is now much simpler and we could just test a simpler scenario
+We keep it the test this way in case new complexity is injected.
 
   $ hg clone -q -u . b b2
   $ cd b2
@@ -282,7 +283,7 b' also, the parent of a node that is a chi'
   $ hg strip 4
   saved backup bundle to $TESTTMP/b2/.hg/strip-backup/8a5212ebc852-backup.hg (glob)
 
-  $ cat $TESTTMP/b2/.hg/cache/branchheads
+  $ cat $TESTTMP/b2/.hg/cache/branchheads-served
   c65502d4178782309ce0574c5ae6ee9485a9bafa 4
   2870ad076e541e714f3c2bc32826b5c6a6e5b040 default
   c65502d4178782309ce0574c5ae6ee9485a9bafa default