tests/test-narrow-merge.t

copies: filter out copies from non-existent source later in _chain()

_changesetforwardcopies() repeatedly calls _chain(). That is very
expensive because _chain() does lookups in the manifest. I hope to
split up the function in two parts: 1) simple chaining, not
considering end points, and 2) filter out files that don't exist in
the end points (and ping-pong copies/renames).

This patches gets us closer to that by moving the check for
non-existent source later in the function. Now there are no more
checks for "src" and "dst" in the first loop; all the filtering of
invalid copies is done in the second loop. The code also looks much
more consistent now.

No measureable impact on `hg debugpathcopies 4.0 4.8`. That shouldn't
be surprising since the only case we're doing more checks now is in
case of chained copies/renames, which are quire rare in practice.

Differential Revision: https://phab.mercurial-scm.org/D6277

#testcases flat tree

  $ . "$TESTDIR/narrow-library.sh"

#if tree
  $ cat << EOF >> $HGRCPATH
  > [experimental]
  > treemanifest = 1
  > EOF
#endif

create full repo

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF

  $ mkdir inside
  $ echo inside1 > inside/f1
  $ echo inside2 > inside/f2
  $ mkdir outside
  $ echo outside1 > outside/f1
  $ echo outside2 > outside/f2
  $ hg ci -Aqm 'initial'

  $ echo modified > inside/f1
  $ hg ci -qm 'modify inside/f1'

  $ hg update -q 0
  $ echo modified > inside/f2
  $ hg ci -qm 'modify inside/f2'

  $ hg update -q 0
  $ echo modified2 > inside/f1
  $ hg ci -qm 'conflicting inside/f1'

  $ hg update -q 0
  $ echo modified > outside/f1
  $ hg ci -qm 'modify outside/f1'

  $ hg update -q 0
  $ echo modified2 > outside/f1
  $ hg ci -qm 'conflicting outside/f1'

  $ cd ..

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 5 changes to 2 files (+4 heads)
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow

  $ hg update -q 0

Can merge in when no files outside narrow spec are involved

  $ hg update -q 'desc("modify inside/f1")'
  $ hg merge 'desc("modify inside/f2")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m 'merge inside changes'

Can merge conflicting changes inside narrow spec

  $ hg update -q 'desc("modify inside/f1")'
  $ hg merge 'desc("conflicting inside/f1")' 2>&1 | egrep -v '(warning:|incomplete!)'
  merging inside/f1
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  $ echo modified3 > inside/f1
  $ hg resolve -m
  (no more unresolved files)
  $ hg commit -m 'merge inside/f1'

TODO: Can merge non-conflicting changes outside narrow spec

  $ hg update -q 'desc("modify inside/f1")'
  $ hg merge 'desc("modify outside/f1")'
  abort: merge affects file 'outside/f1' outside narrow, which is not yet supported (flat !)
  abort: merge affects file 'outside/' outside narrow, which is not yet supported (tree !)
  (merging in the other direction may work)
  [255]

  $ hg update -q 'desc("modify outside/f1")'
  $ hg merge 'desc("modify inside/f1")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge from inside to outside'

Refuses merge of conflicting outside changes

  $ hg update -q 'desc("modify outside/f1")'
  $ hg merge 'desc("conflicting outside/f1")'
  abort: conflict in file 'outside/f1' is outside narrow clone (flat !)
  abort: conflict in file 'outside/' is outside narrow clone (tree !)
  [255]