[PATCH disable-tools] merge-tools: allow marking a mergetool as completely disabled

[Augie Fackler]

> On Oct 16, 2015, at 11:24, Yuya Nishihara <yuya at tcha.org> wrote:
> 
> On Wed, 14 Oct 2015 13:27:46 -0400, Augie Fackler wrote:
>> # HG changeset patch
>> # User Augie Fackler <augie at google.com>
>> # Date 1444841853 14400
>> #      Wed Oct 14 12:57:33 2015 -0400
>> # Node ID a9313815992aa2f0af995762eaca6aa926358bfc
>> # Parent  335b06e9a9cab0bebb527718e1c80daf1560141d
>> 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.
>> 
>> diff --git a/mercurial/filemerge.py b/mercurial/filemerge.py
>> --- a/mercurial/filemerge.py
>> +++ b/mercurial/filemerge.py
>> @@ -120,12 +120,15 @@ def _picktool(repo, ui, path, binary, sy
>> 
>>     # then merge tools
>>     tools = {}
>> +    disabled = set()
>>     for k, v in ui.configitems("merge-tools"):
>>         t = k.split('.')[0]
>>         if t not in tools:
>>             tools[t] = int(_toolstr(ui, t, "priority", "0"))
>> +        if _toolbool(ui, t, "disabled", False):
>> +            disabled.add(t)
>>     names = tools.keys()
>> -    tools = sorted([(-p, t) for t, p in tools.items()])
>> +    tools = sorted([(-p, t) for t, p in tools.items() if t not in disabled])
>>     uimerge = ui.config("ui", "merge")
>>     if uimerge:
>>         if uimerge not in names:
>> diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
>> --- a/mercurial/help/config.txt
>> +++ b/mercurial/help/config.txt
>> @@ -1004,7 +1004,10 @@ Example ``~/.hgrc``::
>>   kdiff3.priority = 1
>> 
>>   # Changing the priority of preconfigured tool
>> -  vimdiff.priority = 0
>> +  meld.priority = 0
>> +
>> +  # Disable a preconfigured tool
>> +  vimdiff.disabled = yes
> 
> I agree vimdiff is annoying. I think it'll be nice if vimdiff is opt-in (i.e.
> disabled by default). As "disabled" tools can be selected by ui.merge, it just
> means priority = -inf.

Yup, but that's (intentionally) beyond the scope of this patch - I just want to be able to have an obvious "make it stop" switch users can flip on merge tools they never want to see.