Re: Re*: git log --name-only improvement: show old file name in rename

[Nathan Faulkner <natedogith1@gmail.com>]

On 5/17/2024 12:00 PM, Junio C Hamano wrote:
> Nathan Faulkner <natedogith1@gmail.com> writes:
> 
>> The documentation for --name-only says "Show only names of changed
>> files." I would interpret this to mean "output the names of all files
>> that changed", not "output the names of all files that changed, unless
>> git detected it as renamed".
> 
> Interesting observation, but we do show renamed files no?  Even when
> there is no content changes?  A quick experiment tells me it does,
> so "unless" is not quite correct.

It seems to me it's not showing the names of all files.  If a file was 
created and a separate file was deleted, but git happens to detect it as 
a rename, it will only show the created file even though from my 
perspective both files changed.

Though even for a true rename, I'd have expected --name-only to show all 
paths that changed (what you want if you're trying to find code owners 
or determine what needs to be rebuilt).

> diff --git c/Documentation/diff-options.txt w/Documentation/diff-options.txt
> index 0e9456957e..b9eaea32d9 100644
> --- c/Documentation/diff-options.txt
> +++ w/Documentation/diff-options.txt
> @@ -329,7 +329,8 @@ explained for the configuration variable `core.quotePath` (see
>   linkgit:git-config[1]).
>   
>   --name-only::
> -	Show only names of changed files. The file names are often encoded in UTF-8.
> +	Show only the name in the before-tree of changed files.
> +	The file names are often encoded in UTF-8.
>   	For more information see the discussion about encoding in the linkgit:git-log[1]
>   	manual page.
>   

That description sounds to me like it only shows files that existed in 
the from-commit, not any files that were created in the to-commit.

If the description is updated, it'd probably be a good idea to 
explicitly call out that --no-renames can be used to get the expected 
behavior of showing all files that changed.


This behavior can also lead to a situation where git diff --name-only 
stops reporting a file as changed when including a newer commit that 
doesn't involve the file.

$ echo '{}' > foo.json; git add .; git commit -m foo
$ rm foo.json; git add .; git commit -m delete
$ echo '{}' > bar.json; git add .; git commit -m bar

$ git diff --name-only HEAD~2 HEAD~1
foo.json
$ git diff --name-only HEAD~1 HEAD
bar.json
$ git diff --name-only HEAD~2 HEAD
bar.json