Re: Bug Report: Superfluous Tab Characters

From: Martin Ågren <martin.agren@gmail.com>
Date: Feb 5, 2023, 15:28 UTC
Message-ID: <CAN0heSruSHQk8cPZ1-Zhp8dfL+j-OAsASrsBTVdWKQcx14Pxtw@mail.gmail.com>
In-Reply-To: <CADPR2CXR_KRKFjPA-0ZuHGHHq_-epHXtJWCuwYx6uvLF_H49mg@mail.gmail.com>

On Sat, 4 Feb 2023 at 13:54, Diogo Fernandes <diogoabfernandes@gmail.com> wrote:

Show 15 quoted lines

> On Fri, 3 Feb 2023 at 14:43 Martin Ågren <martin.agren@gmail.com> wrote:
>>
>> On Fri, 3 Feb 2023 at 13:50, Diogo Fernandes <diogoabfernandes@gmail.com> wrote:
>> >
>> > I have run into a bug where git seems to be adding superfluous tabs to
>> > the end of filenames that contain a space. I have attached the output
>> > of `git bugreport` for your review. Feel free to have a look
>> > https://github.com/trufflesecurity/trufflehog/issues/1060 for
>> > additional context.
>>
>> The code that adds this tab in the output of `git log` and friends has
>> changed a bit since it was originally added in 1a9eb3b9d5
>> ("git-diff/git-apply: make diff output a bit friendlier to GNU patch
>> (part 2)", 2006-09-22), but in that commit you can see the original
>> motivation.

> So, this is by design and not a bug? And is it still current in the latest version of git?

Yes, it appears to be by design:

    Somebody was wondering on #git channel why a git generated diff
    does not apply with GNU patch when the filename contains a SP.
    It is because GNU patch expects to find TAB (and trailing timestamp)
    on ---/+++ (old_name and new_name) lines after the filenames.

    The "diff --git" output format was carefully designed to be
    compatible with GNU patch where it can, but whitespace
    characters were always a pain.

    This adds an extra TAB (but not trailing timestamp) to old_name
    and new_name lines of git-diff output when the filename has a SP
    in it.  An earlier patch updated git-apply to prepare for this.

From a quick test, this behavior does seem to be in newest git.

I sense there is some sort of ulterior motive here that hasn't come across yet. Are you trying to parse the output of `git log` to find something? Would `git diff-tree` work, e.g., if you're mostly just after the filenames involved? Depending on what you're trying to achieve, it could be a bit simpler to parse `git diff-tree` and other "plumbing" commands, rather than `git log` and other such "porcelain" commands.

(Also, note that one person's `git log` output can be different from yours, e.g., because of various config knobs being set different ways.)

Martin