diff tests/test-newbranch.t @ 18234:a55b06885cda

branchmap: allow to use cache of subset

Filtered repository are *subset* of unfiltered repository. This means that a
filtered branchmap could be use to compute the unfiltered version.

And filtered version happen to be subset of each other:
- "all() - unserved()" is a subset of "all() - hidden()"
- "all() - hidden()" is a subset of "all()"

This means that branchmap with "unfiltered" filter can be used as a base for
"hidden" branchmap that itself could be used as a base for unfiltered
branchmap.

   unserved < hidden < None

This changeset implements this mechanism. If the on disk branchcache is not valid
we use the branchcache of the nearest subset as base instead of computing it from
scratch. Such fallback can be cascaded multiple time is necessary.

Note that both "hidden" and "unserved" set are a bit volatile. We will add more
stable filtering in next changesets.

This changeset enables collaboration between no filtering and "unserved"
filtering. Fixing performance regression introduced by 47f00b0de337

--- a/tests/test-newbranch.t	Mon Jan 07 17:16:24 2013 +0100
+++ b/tests/test-newbranch.t	Mon Jan 07 17:23:25 2013 +0100
@@ -1,5 +1,15 @@
   $ branchcache=.hg/cache/branchheads
 
+  $ listbranchcaches() {
+  >    for f in .hg/cache/branchheads*;
+  >       do echo === $f ===;
+  >       cat $f;
+  >     done;
+  > }
+  $ purgebranchcaches() {
+  >     rm .hg/cache/branchheads*
+  > }
+
   $ hg init t
   $ cd t
 
@@ -112,7 +122,7 @@
   repository tip rolled back to revision 4 (undo commit)
   working directory now based on revisions 4 and 3
 
-  $ cp $branchcache .hg/bc-invalid
+  $ cp ${branchcache}-unserved .hg/bc-invalid
 
   $ hg log -r foo
   changeset:   4:adf1a74a7f7b
@@ -142,13 +152,16 @@
   modify a branch
   
   
-  $ rm $branchcache
+  $ purgebranchcaches
   $ echo corrupted > $branchcache
 
   $ hg log -qr foo
   4:adf1a74a7f7b
 
-  $ cat $branchcache
+  $ listbranchcaches
+  === .hg/cache/branchheads ===
+  corrupted
+  === .hg/cache/branchheads-unserved ===
   adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 4
   1c28f494dae69a2f8fc815059d257eccf3fcfe75 default
   adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 foo
@@ -162,7 +175,8 @@
 
   $ hg push -qr 0 ../target
 
-  $ cat ../target/$branchcache
+  $ (cd ../target/; listbranchcaches)
+  === .hg/cache/branchheads-unserved ===
   db01e8ea3388fd3c7c94e1436ea2bd6a53d581c5 0
   db01e8ea3388fd3c7c94e1436ea2bd6a53d581c5 default
 
@@ -170,7 +184,8 @@
 
   $ hg push -qf ../target
 
-  $ cat ../target/$branchcache
+  $ (cd ../target/; listbranchcaches)
+  === .hg/cache/branchheads-unserved ===
   adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 4
   1c28f494dae69a2f8fc815059d257eccf3fcfe75 default
   adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 foo