Re: git 2.34.0: Behavior of `**` in gitignore is different from previous versions.

From: Danial Alihosseini <danial.alihosseini@gmail.com>
Date: Nov 19, 2021, 04:01 UTC
Message-ID: <CACLOEFbY3LwMa2uhc=9jmcGFf0mvWzEM=YityLyFcuGWXVmqbw@mail.gmail.com>
In-Reply-To: <2bd2269f-c7f1-7afb-7052-48fac148dffd@gmail.com>

Thanks for your follow-up.

I wanted to ignore all files in the "data" folder except ".txt" ones.

As mentioned in the gitignore doc, there should be a difference between "**" and "**/".

> A trailing "/**" matches everything inside. For example, "abc/**" matches all files inside directory "abc", relative to the location of the .gitignore file, with infinite depth.

and,

>
> A slash followed by two consecutive asterisks then a slash matches zero or more directories. For example, "a/**/b" matches "a/b", "a/x/b", "a/x/y/b" and so on.

and also,

>
> It is not possible to re-include a file if a parent directory of that file is excluded.

So, I excluded all files by "data/**", re-included just directories (at any depth) by "!data/**/" and, re-included ".txt" files (at any depth) by "!data/**/*.txt". However, if I wanted to re-include a directory and all of its contents, I could use something like "!data/data1/**", without trailing slash. As I see, there is no separation between "**" and "**/" in the current version.

I think there is another point that the previous behavior test case
should be like this:
test_expect_success 'directories and ** matches' '
    cat >.gitignore <<-\EOF &&
    data/**
    !data/**/
    !data/**/*.txt
    EOF
    git check-ignore file \
        data/file data/data1/file1 data/data1/file1.txt \
        data/data2/file2 data/data2/file2.txt >actual &&
    cat >expect <<-\EOF &&
    data/file
    data/data1/file1
    data/data2/file2
    EOF
    test_cmp expect actual
'
Thanks
Danial

On Fri, Nov 19, 2021 at 1:40 AM Derrick Stolee <stolee@gmail.com> wrote:

Show 91 quoted lines

>
> On 11/18/2021 12:04 PM, Jeff King wrote:
> > On Thu, Nov 18, 2021 at 08:11:04PM +0330, Danial Alihosseini wrote:
> >
> >> What did you do before the bug happened? (Steps to reproduce your issue)
> >> Consider the following project structure
> >> - data
> >>   - data1
> >>     - file1
> >>     - file1.txt
> >>   - data2
> >>     - file2
> >>     - file2.txt
> >> - .gitignore
> >>
> >>
> >> `.gitignore` is as follows:
> >> ```
> >> data/**
> >> !data/**/
> >> !data/**/*.txt
> >> ```
> >> What did you expect to happen? (Expected behavior)
> >>
> >> I expect all files in `data` folder to be ignored except `.txt` files.
> >>
> >> What happened instead? (Actual behavior)
> >>
> >> `file1` and `file2` are not ignored.
> >> Here is the `check-ignore` output:
> >> ```
> >> $ git check-ignore -v data/data1/file1
> >> .gitignore:2:!/data/**/ data/data1/file1
> >> ```
> >
> > Thanks for an easy reproduction. It looks like this changed in
> > f6526728f9 (dir: select directories correctly, 2021-09-24). Author cc'd.
>
> Thanks for the bisect and CC.
>
> > The key thing seems to be that the second line of your .gitignore should
> > match only directories (because of the trailing slash), but no longer
> > does.
>
> Doesn't "matching only directories" mean it would match everything
> within that directory? (It also means that "data/file" is not matched,
> which is still correct.)
>
> My interpretation of these patterns is that everything in data/data1/
> and data/data2/ should not be ignored, making it seem like the change
> fixed a bug (it definitely changed behavior).
>
> Just for extra clarity, this test currently passes:
>
> test_expect_success 'directories and ** matches' '
>         cat >.gitignore <<-\EOF &&
>         data/**
>         !data/**/
>         !data/**/*.txt
>         EOF
>         git check-ignore file \
>                 data/file data/data1/file1 data/data1/file1.txt \
>                 data/data2/file2 data/data2/file2.txt >actual &&
>         cat >expect <<-\EOF &&
>         data/file
>         EOF
>         test_cmp expect actual
> '
>
> but the previous behavior would have passed this test:
>
> test_expect_success 'directories and ** matches' '
>         cat >.gitignore <<-\EOF &&
>         data/**
>         !data/**/
>         !data/**/*.txt
>         EOF
>         git check-ignore file \
>                 data/file data/data1/file1.txt \
>                 data/data2/file2.txt >actual &&
>         cat >expect <<-\EOF &&
>         data/file
>         EOF
>         test_cmp expect actual
> '
>
> I seek more clarity on this. Specifically: if we match a directory
> then should we not also match the contents within?
>
> Thanks,
> -Stolee