Re: [PATCH v3 4/8] merge-recursive: new function for better colliding conflict resolutions

From: Derrick Stolee <stolee@gmail.com>
To: Elijah Newren <newren@gmail.com>, git@vger.kernel.org
Cc: gitster@pobox.com
Subject: Re: [PATCH v3 4/8] merge-recursive: new function for better colliding conflict resolutions
Date: Wed, 31 Oct 2018 09:57:37 -0400	[thread overview]
Message-ID: <95a236fd-a757-81ad-34aa-b26b3c3b6e85@gmail.com> (raw)
In-Reply-To: <0b84c95b-38bc-e39e-a033-81eb3e7b8202@gmail.com>

On 10/31/2018 9:53 AM, Derrick Stolee wrote:
> On 10/19/2018 3:31 PM, Elijah Newren wrote:
>> +#if 0 // #if-0-ing avoids unused function warning; will make live in 
>> next commit
>> +static int handle_file_collision(struct merge_options *o,
>> +                 const char *collide_path,
>> +                 const char *prev_path1,
>> +                 const char *prev_path2,
>> +                 const char *branch1, const char *branch2,
>> +                 const struct object_id *a_oid,
>> +                 unsigned int a_mode,
>> +                 const struct object_id *b_oid,
>> +                 unsigned int b_mode)
>> +{
>> +    struct merge_file_info mfi;
>> +    struct diff_filespec null, a, b;
>> +    char *alt_path = NULL;
>> +    const char *update_path = collide_path;
>> +
>> +    /*
>> +     * In the recursive case, we just opt to undo renames
>> +     */
>> +    if (o->call_depth && (prev_path1 || prev_path2)) {
>> +        /* Put first file (a_oid, a_mode) in its original spot */
>> +        if (prev_path1) {
>> +            if (update_file(o, 1, a_oid, a_mode, prev_path1))
>> +                return -1;
>> +        } else {
>> +            if (update_file(o, 1, a_oid, a_mode, collide_path))
>
> The latest test coverage report [1] shows this if statement is never 
> run, so
> it appears that every call to this method in the test suite has either
> o->call_depth positive, prev_path1 non-NULL, or both prev_path1 and 
> prev_path2
> NULL.
>
> Is there a way we can add a test case that calls this method with 
> o->call_depth
> positive, prev_path1 NULL, and prev_path2 non-NULL?
>
>> +                return -1;
>> +        }
>> +
>> +        /* Put second file (b_oid, b_mode) in its original spot */
>> +        if (prev_path2) {
>> +            if (update_file(o, 1, b_oid, b_mode, prev_path2))
>
> Since this line is covered, we _do_ call the method with prev_path2 
> non-NULL, but
> prev_path1 must be non-NULL in all cases.
>
> I may have found a reason why this doesn't happen in one of the 
> callers you introduced.
> I'm going to comment on PATCH 8/8 to see if that is the case.

Nevermind on the PATCH 8/8 situation. I thought I saw you pass (a->path, 
NULL) and
(b->path, NULL) into the (prev_path1, prev_path2) pairs, but in each 
case the non-NULL
parameter is actually for 'collide_path'.

It is still interesting if we can hit this case. Perhaps we need a 
different kind of
conflict, like (rename, delete) [but I struggle to make sense of how to 
do that].

Thanks,
-Stolee