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 a
$ cd a
$ touch empty1
$ hg add empty1
$ hg commit -m 'add empty1'
$ touch empty2
$ hg add empty2
$ hg commit -m 'add empty2'
$ hg up -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ touch empty3
$ hg add empty3
$ hg commit -m 'add empty3'
created new head
$ hg heads
changeset: 2:a1cb177e0d44
tag: tip
parent: 0:1e1d9c4e5b64
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: add empty3
changeset: 1:097d2b0e17f6
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: add empty2
$ hg merge 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
Before changeset 05257fd28591, we didn't notice the
empty file that came from rev 1:
$ hg status
M empty2
$ hg commit -m merge
$ hg manifest --debug tip
b80de5d138758541c5f05265ad144ab9fa86d1db 644 empty1
b80de5d138758541c5f05265ad144ab9fa86d1db 644 empty2
b80de5d138758541c5f05265ad144ab9fa86d1db 644 empty3
$ cd ..