Subject: Re: [PATCH v4 8/9] checkout: add advice for ambiguous "checkout <branch>"

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Fri, 01 Jun 2018 11:50:14 +0200

On Fri, Jun 01 2018, Junio C Hamano wrote:

> Ævar Arnfjörð Bjarmason  <[email-masked]> writes:
>
>> @@ -1269,6 +1270,16 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
>>  	if (opts.patch_mode || opts.pathspec.nr) {
>>  		int ret = checkout_paths(&opts, new_branch_info.name,
>>  					 &dwim_remotes_matched);
>> +		if (ret && dwim_remotes_matched > 1 &&
>> +		    advice_checkout_ambiguous_remote_branch_name)
>> +			advise(_("The argument '%s' matched more than one remote tracking branch.\n"
>> +				 "We found %d remotes with a reference that matched. So we fell back\n"
>> +				 "on trying to resolve the argument as a path, but failed there too!\n"
>> +				 "\n"
>> +				 "Perhaps you meant fully qualify the branch name? E.g. origin/<name>\n"
>> +				 "instead of <name>?"),
>> +			       argv[0],
>> +			       dwim_remotes_matched);
>>  		return ret;
>
> Do we give "checkout -p no-such-file" the above wall of text?

No:

    $ ./git --exec-path=$PWD checkout -p master
    No changes.
    $ ./git --exec-path=$PWD checkout master
    error: pathspec 'master' did not match any file(s) known to git.
    hint: The argument 'master' matched more than one remote tracking branch.
    [...]

> Somehow checkout_paths(), which is "we were given a tree-ish and
> pathspec and told to grab the matching paths out of it and stuff
> them to the index and the working tree", is a wrong place to be
> doing the "oh, what the caller thought was pathspec may turn out to
> be a rev, so check that too for such a confused caller".  Shouldn't
> the caller be doing all that (which would mean we wan't need to pass
> "remotes-matched" to the function, as the helper has nothing to do
> with deciding which arg is the tree-ish).

I skimmed the rest of this thread and saw there were more specific
suggestions. I'm open to moving this somewhere else. The "what is this
and what do we do" logic in checkout.c is spread over multiple
functions, and this seemed the most straightforward way to add this.