view tests/test-issue612.t @ 32903:27932a76a88d

dagop: split module hosting DAG-related algorithms from revset

This module hosts the following functions. They are somewhat similar (e.g.
scanning revisions using heap queue or stack) and seem non-trivial in
algorithmic point of view.

 - _revancestors()
 - _revdescendants()
 - reachableroots()
 - _toposort()

I was thinking of adding revset._fileancestors() generator for better follow()
implementation, but it would be called from context.py as well. So I decided
to create new module.

Naming is hard. I couldn't come up with any better module name, so it's called
"dag operation" now. I rejected the following candidates:

 - ancestor.py - existing, revlog-level DAG algorithm
 - ancestorset.py - doesn't always return a set
 - dagalgorithm.py - hard to type
 - dagutil.py - existing
 - revancestor.py - I want to add fileancestors()

  % wc -l mercurial/dagop.py mercurial/revset.py
    339 mercurial/dagop.py
   2020 mercurial/revset.py
   2359 total

https://bz.mercurial-scm.org/612

  $ hg init
  $ mkdir src
  $ echo a > src/a.c
  $ hg ci -Ama
  adding src/a.c

  $ hg mv src source
  moving src/a.c to source/a.c (glob)

  $ hg ci -Ammove

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

  $ echo new > src/a.c
  $ echo compiled > src/a.o
  $ hg ci -mupdate
  created new head

  $ hg status
  ? src/a.o

  $ hg merge
  merging src/a.c and source/a.c to source/a.c
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status
  M source/a.c
  R src/a.c
  ? src/a.o