Subject: Re: Incorrect behavior from git checkout --patch

From: Phillip Wood <[email-masked]>
Date: Sun, 11 Aug 2019 14:47:45 +0100

Hi Dave

On 11/08/2019 10:54, Phillip Wood wrote:
> Hi Dave
> 
> Thanks for the bug report. I've tried to reproduce it on the latest 
> master, version 2.22.0 and 2.20.1 and am unable to do so.

Doh, I was doing 'git checkout -p HEAD', when I checkout from the index 
I can reproduce the bug and it is fixed by the patch I linked to earlier 
which will be in git 2.23.0. That will be released soon (we're at 
2.23.0.rc2 at the moment)

Thanks again for taking the time to report the bug

Best Wishes

Phillip

> I thought it 
> might be related to a bug I recently fixed[1] but it does not appear to 
> be. I've appended the files I used below just in case I made a mistake 
> translating your patches to files that can be used with git checkout.
> 
> Best Wishes
> 
> Phillip
> 
> [1] 
> https://github.com/git/git/commit/1b074e15d0f976be2bc14f9528874a841c055213#diff-588be9a03d1f7e33db12f186aad5fde9 
> 
> 
> pre-image
> 
> block_one {
> line 1
> line 2
> line 3
> 2 4 6 8
> line 4
> line 5
> line 6
> 2 4 6 8
> line 7
> line 8
> line 9
> 2 4 6 8
> line 10
> line 11
> line 12
> }
> 
> block_two {
> line 1
> line 2
> line 3
> 2 5 6 9
> line 4
> line 5
> line 6
> 2 5 6 9
> line 7
> line 8
> line 9
> 2 5 6 9
> line 10
> line 11
> line 12
> }
> 
> post-image
> 
> block_one {
> line 1
> line 1.5
> line 2
> line 2.5
> line 3
> 2 4 6 8
> line 4
> line 4.5
> line 5
> line 5.5
> line 6
> 2 4 6 8
> line 7
> line 7.5
> line 8
> line 8.5
> line 9
> 2 4 6 8
> line 10
> line 10.5
> line 11
> line 11.5
> line 12
> }
> 
> block_two {
> line 1
> line 1.5
> line 2
> line 2.5
> line 3
> 2 5 6 9
> line 4
> line 4.5
> line 5
> line 5.5
> line 6
> 2 5 6 9
> line 7
> line 7.5
> line 8
> line 8.5
> line 9
> 2 5 6 9
> line 10
> line 10.5
> line 11
> line 11.5
> line 12
> }
> 
> 
> 
> On 10/08/2019 21:12, Dave Kaminski wrote:
>> I am observing git checkout --patch making changes to the wrong lines 
>> of a file.
>>
>> This is with a clean install of git version 2.20.1 on a debian docker
>> container (image tag 10.0 which is also "latest" as of this writing).
>>
>> With a diff that looks like the following:
>>
>> diff --git a/file.txt b/file.txt
>> index 868aa22..ea4d786 100644
>> --- a/file.txt
>> +++ b/file.txt
>> @@ -1,35 +1,51 @@
>>   block_one {
>>   line 1
>> +line 1.5
>>   line 2
>> +line 2.5
>>   line 3
>>   2 4 6 8
>>   line 4
>> +line 4.5
>>   line 5
>> +line 5.5
>>   line 6
>>   2 4 6 8
>>   line 7
>> +line 7.5
>>   line 8
>> +line 8.5
>>   line 9
>>   2 4 6 8
>>   line 10
>> +line 10.5
>>   line 11
>> +line 11.5
>>   line 12
>>   }
>>
>>   block_two {
>>   line 1
>> +line 1.5
>>   line 2
>> +line 2.5
>>   line 3
>> -2 5 6 9
>> +2 4 6 8
>>   line 4
>> +line 4.5
>>   line 5
>> +line 5.5
>>   line 6
>> -2 5 6 9
>> +2 4 6 8
>>   line 7
>> +line 7.5
>>   line 8
>> +line 8.5
>>   line 9
>> -2 5 6 9
>> +2 4 6 8
>>   line 10
>> +line 10.5
>>   line 11
>> +line 11.5
>>   line 12
>>   }
>>
>> doing a `git checkout --patch -- ./file.txt`, splitting the diff into
>> hunks, and discarding all of the hunks that begin with numbers, e.g.
>>
>> @@ -22,3 +32,3 @@
>>   line 3
>> -2 5 6 9
>> +2 4 6 8
>>   line 4
>>
>> the expected state of the file in the working directory is this:
>>
>> diff --git a/file.txt b/file.txt
>> index 868aa22..9ab67a1 100644
>> --- a/file.txt
>> +++ b/file.txt
>> @@ -1,35 +1,51 @@
>>   block_one {
>>   line 1
>> +line 1.5
>>   line 2
>> +line 2.5
>>   line 3
>>   2 4 6 8
>>   line 4
>> +line 4.5
>>   line 5
>> +line 5.5
>>   line 6
>>   2 4 6 8
>>   line 7
>> +line 7.5
>>   line 8
>> +line 8.5
>>   line 9
>>   2 4 6 8
>>   line 10
>> +line 10.5
>>   line 11
>> +line 11.5
>>   line 12
>>   }
>>
>>   block_two {
>>   line 1
>> +line 1.5
>>   line 2
>> +line 2.5
>>   line 3
>>   2 5 6 9
>>   line 4
>> +line 4.5
>>   line 5
>> +line 5.5
>>   line 6
>>   2 5 6 9
>>   line 7
>> +line 7.5
>>   line 8
>> +line 8.5
>>   line 9
>>   2 5 6 9
>>   line 10
>> +line 10.5
>>   line 11
>> +line 11.5
>>   line 12
>>   }
>>
>> but instead the actual state of the file is this:
>>
>> diff --git a/file.txt b/file.txt
>> index 868aa22..76fe65d 100644
>> --- a/file.txt
>> +++ b/file.txt
>> @@ -1,35 +1,51 @@
>>   block_one {
>>   line 1
>> +line 1.5
>>   line 2
>> +line 2.5
>>   line 3
>>   2 4 6 8
>>   line 4
>> +line 4.5
>>   line 5
>> +line 5.5
>>   line 6
>>   2 4 6 8
>>   line 7
>> +line 7.5
>>   line 8
>> +line 8.5
>>   line 9
>> -2 4 6 8
>> +2 5 6 9
>>   line 10
>> +line 10.5
>>   line 11
>> +line 11.5
>>   line 12
>>   }
>>
>>   block_two {
>>   line 1
>> +line 1.5
>>   line 2
>> +line 2.5
>>   line 3
>>   2 5 6 9
>>   line 4
>> +line 4.5
>>   line 5
>> +line 5.5
>>   line 6
>>   2 5 6 9
>>   line 7
>> +line 7.5
>>   line 8
>> +line 8.5
>>   line 9
>> -2 5 6 9
>> +2 4 6 8
>>   line 10
>> +line 10.5
>>   line 11
>> +line 11.5
>>   line 12
>>   }
>>
>> See the changes between "line 9" and "line 10" in both blocks that are
>> not correct.
>>