tests/test-basic.t

windows: recompute flags when committing a merge (issue1802)

Before this patch, Windows always did the wrong thing with exec bits
when committing a merge: consult the flags in first parent.

Now we manually recompute the result of merging flags at commit time,
which almost always does the right thing (except when there are
conflicts between symlink and exec flags).

To do this, we:

- pull flag synthesis out into its own function
- delay building this function unless it's needed
- add a merge case that compares flags in local and other against the ancestor

This has been tested in multiple ways on Linux:

- running the whole test suite with both old and new code in place,
  checking for differences in each flags() result
- running the whole test suite while comparing real on-disk flags
  against synthetic ones for merges
- test-issue1802 (from Martin Geisler) which disables exec bit
  checking on Unix

Create a repository:

  $ hg init t
  $ cd t

Make a changeset:

  $ echo a > a
  $ hg add a
  $ hg commit -m test

This command is ancient:

  $ hg history
  changeset:   0:acb14030fe0a
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  

Verify that updating to revision 0 via commands.update() works properly

  $ cat <<EOF > update_to_rev0.py
  > from mercurial import ui, hg, commands
  > myui = ui.ui()
  > repo = hg.repository(myui, path='.')
  > commands.update(myui, repo, rev=0)
  > EOF
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ python ./update_to_rev0.py
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg identify -n
  0
 

Poke around at hashes:

  $ hg manifest --debug
  b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644   a

  $ hg cat a
  a

Verify should succeed:

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions

At the end...