tests/test-push-hook-lock.t

merge-tools: allow marking a mergetool as completely disabled

Very often in my life I'm finding that the only configured merge tool
present on the system is vimdiff[0], and it's currently impossible (as
far as I can tell) short of specifying `ui.merge = `[1] to actually
*disable* a merge tool. This allows vimdiff-haters to put:

  [merge-tools]
  vimdiff.disable = yes

in their ~/.hgrc and never see vimdiff again. I'm stopping short of
putting this as a commented out entry in the sample new user hgrc
(seen when a user runs `hg config --edit` with no ~/.hgrc) for now,
but I might come back and do that later.

0: vimdiff is at an awkward intersection: it's usually installed by
the vim package which is often installed as a vi substitute, so it's
mere presence doesn't imply me wanting it, unlike (say) kdiff3.

1: There's a related problem I ran into today where specifying
`ui.merge = :merge` failed because :merge isn't a command, which I
think is a regression. I'll try and figure that out and at least file
a bug.

  $ hg init 1

  $ echo '[ui]' >> 1/.hg/hgrc
  $ echo 'timeout = 10' >> 1/.hg/hgrc

  $ echo foo > 1/foo
  $ hg --cwd 1 ci -A -m foo
  adding foo

  $ hg clone 1 2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone 2 3
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cat <<EOF > $TESTTMP/debuglocks-pretxn-hook.sh
  > hg debuglocks
  > true
  > EOF
  $ echo '[hooks]' >> 2/.hg/hgrc
  $ echo "pretxnchangegroup.a = sh $TESTTMP/debuglocks-pretxn-hook.sh" >> 2/.hg/hgrc
  $ echo 'changegroup.push = hg push -qf ../1' >> 2/.hg/hgrc

  $ echo bar >> 3/foo
  $ hg --cwd 3 ci -m bar

  $ hg --cwd 3 push ../2 --config experimental.bundle2-exp=False
  pushing to ../2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  lock:  user *, process * (*s) (glob)
  wlock: free

  $ hg --cwd 1 --config extensions.strip= strip tip -q
  $ hg --cwd 2 --config extensions.strip= strip tip -q
  $ hg --cwd 3 push ../2 --config experimental.bundle2-exp=True
  pushing to ../2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  lock:  user *, process * (*s) (glob)
  wlock: user *, process * (*s) (glob)