Re: [PATCH v6 1/2] t1092: add tests for `git diff-files`

From: Victoria Dye <vdye@github.com>
Date: Mar 21, 2023, 21:21 UTC
Message-ID: <d940fe05-de86-5069-1d77-f4c7d0d368b6@github.com>
In-Reply-To: <20230320205241.105476-2-cheskaqiqi@gmail.com>

Shuqi Liang wrote:

Show 18 quoted lines

> Before integrating the 'git diff-files' builtin
> with the sparse index feature, add tests to
> t1092-sparse-checkout-compatibility.sh to ensure it currently works
> with sparse-checkout and will still work with sparse index
> after that integration.
> 
> When adding tests against a sparse-checkout
> definition, we test two modes: all changes are
> within the sparse-checkout cone and some changes are outside
> the sparse-checkout cone.
> 
> In order to have staged changes outside of
> the sparse-checkout cone, make a directory called 'folder1' and
> copy `a` into 'folder1/a'. 'folder1/a' is identical to `a` in the base
> commit. These make 'folder1/a' in the index, while leaving it outside of
> the sparse-checkout definition. Test 'folder1/a'being present on-disk
> without modifications, then change content inside 'folder1/a' in order
> to test 'folder1/a' being present on-disk with modifications.

The word wrapping on this message (and your other commits/cover letter) is a bit strange. By convention, it should be consistently wrapped to 72 columns per line. Most text editors have some way of configuring that so you don't need to do it manually.

Show 35 quoted lines

> 
> Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
> ---
>  t/t1092-sparse-checkout-compatibility.sh | 42 ++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
> index 801919009e..c1329e2f16 100755
> --- a/t/t1092-sparse-checkout-compatibility.sh
> +++ b/t/t1092-sparse-checkout-compatibility.sh
> @@ -2055,4 +2055,46 @@ test_expect_success 'grep sparse directory within submodules' '
>  	test_cmp actual expect
>  '
>  
> +test_expect_success 'diff-files with pathspec inside sparse definition' '
> +	init_repos &&
> +
> +	write_script edit-contents <<-\EOF &&
> +	echo text >>"$1"
> +	EOF
> +
> +	run_on_all ../edit-contents deep/a &&
> +
> +	test_all_match git diff-files &&
> +
> +	test_all_match git diff-files deep/a && 
> +
> +	# test wildcard
> +	test_all_match git diff-files deep/*
> +'
> +
> +test_expect_failure 'diff-files with pathspec outside sparse definition' '
> +	init_repos &&
> +
> +	test_sparse_match test_must_fail git diff-files folder2/a &&

Makes sense. In a sparse-checkout, folder2/a isn't in the working tree, so 'diff-files' (which compares working tree vs. index) doesn't really apply.

Show 9 quoted lines

> +
> +	write_script edit-contents <<-\EOF &&
> +	echo text >>"$1"
> +	EOF
> +
> +	# Add file to the index but outside of cone for sparse-checkout cases.
> +	# Add file to the index without sparse-checkout cases to ensure all have 
> +	# same output.
> +	run_on_all mkdir folder1 &&

The test is failing because of this line. It should be 'mkdir -p folder1'; as you have it now, the command fails because 'folder1' already exists in 'full-checkout'. Alternatively, you could use 'run_on_sparse mkdir folder1', but using '-p' seems like the less fragile approach.

For reference, the way I figured that out was to run 't1092' as follows:

	cd t && ./t1092-sparse-checkout-compatibility.sh -xvdi --run=1,82

What the options correspond to:
* -x: print the commands called in the test (equivalent of calling 'set -x'
      in the test script).
* -v: print stdout/stderr to the console.
* -d: do not remove the "trash directory" of the test.
* -i: stop test execution once it encounters a failure.
* --run: run only the specified tests (1 is the first test - 'setup' - and
         82 is 'diff-files with pathspec outside sparse definition').

Show 5 quoted lines

> +	run_on_all cp a folder1/a &&
> +
> +	# file present on-disk without modifications
> +	test_all_match git diff-files &&
> +	test_all_match git diff-files folder1/a &&

The strange thing is, once I fixed the 'mkdir' issue in my local copy of these patches, these 'test_all_match diff-files' calls succeeded. It turns out that 'git diff-files' in the 'full-checkout', like in 'sparse-checkout', reports a difference in 'folder1/a' that doesn't actually exist. So the bug isn't in sparse-checkout as I initially assumed [1], but rather in diff-files itself.

At this point, I'd say the diff-files bug is out-of-scope of this sparse index integration; in your implementation, sparse-checkout and sparse index work the same as a full checkout, it's just that the "normal" full checkout behavior is wrong. My recommendation would be that you keep this test as-is and, to force the failure, add a check that 'full-checkout-out' is empty. Then, in a "NEEDSWORK" comment on the test (like the one on 'diff with renames and conflicts') that indicates that the 'diff-files' behavior is wrong.

I'll try to make some time this week to look into the 'diff-files' bug. Sorry for the back-and-forth and distraction from your sparse index integration. Other than the 'mkdir' issue, these updated tests look great!

[1] https://lore.kernel.org/git/b537d855-edb7-4f67-de08-d651868247a5@github.com/

Show 8 quoted lines

> +
> +	# file present on-disk with modifications
> +	run_on_all ../edit-contents folder1/a &&
> +	test_all_match git diff-files &&
> +	test_all_match git diff-files folder1/a
> +'
> +
>  test_done