branchmap: update cache of 'unserved' filter on new changesets

The `commitctx` and `addchangegroup` methods of repo upgrade branchcache after
completion. This behavior aims to keep the branchcache in sync for read only
process as hgweb. See ee317dbfb9d0 for details.

Since changelog filtering is used, those calls only update the cache for unfiltered repo.
One of no interest for typical read only process like hgweb.

Note: By chance in basic case, `repo.unfiltered() == repo.filtered('unserved')`

This changesets have the "unserved" cache updated instead. I think this is the
only cache that matter for hgweb.

We could imagine updating all possible branchcaches instead but:
- I'm not sure it would have any benefit impact. It may even increase the odd of
  all cache being invalidated.
- This is more complicated change.

So I'm going for updating a single cache only which is already better that
updating a cache nobody cares about.

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

mercurial/localrepo.py

@@ -1367,7 +1367,7 b' class localrepository(object):'
                 # if minimal phase was 0 we don't need to retract anything
                 phases.retractboundary(self, targetphase, [n])
             tr.close()
-            branchmap.updatecache(self)
+            branchmap.updatecache(self.filtered('served'))
             return n
         finally:
             if tr:
@@ -2388,7 +2388,7 b' class localrepository(object):'
                     # During strip, branchcache is invalid but coming call to
                     # `destroyed` will repair it.
                     # In other case we can safely update cache on disk.
-                    branchmap.updatecache(self)
+                    branchmap.updatecache(self.filtered('served'))
                 def runhooks():
                     # forcefully update the on-disk branch cache
                     self.ui.debug("updating the branch cache\n")

tests/test-keyword.t

@@ -579,6 +579,7 b' Commit and show expansion in original an'
   invalid branchheads cache (served): tip differs
   c
    c: copy a:0045e12f6c5791aac80ca6cbfd97709a88307292
+  invalid branchheads cache (served): tip differs
   overwriting c expanding keywords
   committed changeset 2:25736cf2f5cbe41f6be4e6784ef6ecf9f3bbcc7d
   $ cat a c
@@ -762,7 +763,6 b' Commit with multi-line message and custo'
   $ hg --debug commit -l log -d '2 0' -u 'User Name <[e-mail]>'
   invalid branchheads cache (served): tip differs
   a
-  invalid branchheads cache: tip differs
   invalid branchheads cache (served): tip differs
   overwriting a expanding keywords
   committed changeset 2:bb948857c743469b22bbf51f7ec8112279ca5d83
@@ -805,7 +805,6 b' remove with status checks'
   $ hg debugrebuildstate
   $ hg remove a
   $ hg --debug commit -m rma
-  invalid branchheads cache: tip differs
   committed changeset 3:d14c712653769de926994cf7fbb06c8fbd68f012
   $ hg status
   ? c
@@ -918,7 +917,6 b' kwexpand x/a should abort'
   $ hg --debug commit -m xa -d '3 0' -u 'User Name <[e-mail]>'
   x/a
    x/a: copy a:779c764182ce5d43e2b1eb66ce06d7b47bfe342e
-  invalid branchheads cache: tip differs
   overwriting x/a expanding keywords
   committed changeset 3:b4560182a3f9a358179fd2d835c15e9da379c1e4
   $ cat a

tests/test-mq-symlinks.t

@@ -45,6 +45,7 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-phases.t

@@ -177,16 +177,26 b' check that branch cache with "unserved" '
 
   $ ls ../push-dest/.hg/cache/branchheads*
   ../push-dest/.hg/cache/branchheads-served
+  $ cat ../push-dest/.hg/cache/branchheads-served
+  6d6770faffce199f1fddd1cf87f6f026138cf061 6 465891ffab3c47a3c23792f7dc84156e19a90722
+  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e default
+  6d6770faffce199f1fddd1cf87f6f026138cf061 default
+  $ hg heads -R ../push-dest --template '{rev}:{node} {phase}\n'  #update visible cache too
+  6:6d6770faffce199f1fddd1cf87f6f026138cf061 draft
+  5:2713879da13d6eea1ff22b442a5a87cb31a7ce6a secret
+  3:b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e draft
+  $ ls ../push-dest/.hg/cache/branchheads*
+  ../push-dest/.hg/cache/branchheads-served
   ../push-dest/.hg/cache/branchheads-visible
+  $ cat ../push-dest/.hg/cache/branchheads-served
+  6d6770faffce199f1fddd1cf87f6f026138cf061 6 465891ffab3c47a3c23792f7dc84156e19a90722
+  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e default
+  6d6770faffce199f1fddd1cf87f6f026138cf061 default
   $ cat ../push-dest/.hg/cache/branchheads-visible
   6d6770faffce199f1fddd1cf87f6f026138cf061 6
   b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e default
   2713879da13d6eea1ff22b442a5a87cb31a7ce6a default
   6d6770faffce199f1fddd1cf87f6f026138cf061 default
-  $ cat ../push-dest/.hg/cache/branchheads-served
-  cf9fe039dfd67e829edf6522a45de057b5c86519 4
-  b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e default
-  cf9fe039dfd67e829edf6522a45de057b5c86519 default
 
 
 Restore condition prior extra insertion.