view tests/test-issue522.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

http://mercurial.selenic.com/bts/issue522

In the merge below, the file "foo" has the same contents in both
parents, but if we look at the file-level history, we'll notice that
the version in p1 is an ancestor of the version in p2. This test makes
sure that we'll use the version from p2 in the manifest of the merge
revision.

  $ hg init

  $ echo foo > foo
  $ hg ci -qAm 'add foo'

  $ echo bar >> foo
  $ hg ci -m 'change foo'

  $ hg backout -r tip -m 'backout changed foo'
  reverting foo
  changeset 2:4d9e78aaceee backs out changeset 1:b515023e500e

  $ hg up -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ touch bar
  $ hg ci -qAm 'add bar'

  $ hg merge --debug
    searching for copies back to rev 1
    unmatched files in local:
     bar
  resolving manifests
   overwrite: False, partial: False
   ancestor: bbd179dfa0a7, local: 71766447bdbb+, remote: 4d9e78aaceee
   foo: remote is newer -> g
  updating: foo 1/1 files (100.00%)
  getting foo
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg debugstate | grep foo
  n   0         -2 unset               foo

  $ hg st -A foo
  M foo

  $ hg ci -m 'merge'

  $ hg manifest --debug | grep foo
  c6fc755d7e68f49f880599da29f15add41f42f5a 644   foo

  $ hg debugindex foo
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       5  .....       0 2ed2a3912a0b 000000000000 000000000000 (re)
       1         5       9  .....       1 6f4310b00b9a 2ed2a3912a0b 000000000000 (re)
       2        14       5  .....       2 c6fc755d7e68 6f4310b00b9a 000000000000 (re)