Subject: Re: [PATCH 8/8] sparse-checkout: integrate with sparse index

From: Derrick Stolee <[email-masked]>
Date: Tue, 17 May 2022 09:28:06 -0400

On 5/16/2022 4:38 PM, Victoria Dye wrote:
> Derrick Stolee via GitGitGadget wrote:
>> From: Derrick Stolee <[email-masked]>

>> +test_expect_success 'sparse index is not expanded: sparse-checkout' '
>> +	init_repos &&
>> +
>> +	ensure_not_expanded sparse-checkout set deep/deeper2 &&
>> +	ensure_not_expanded sparse-checkout set deep/deeper1 &&
>> +	ensure_not_expanded sparse-checkout set deep &&
>> +	ensure_not_expanded sparse-checkout add folder1 &&
>> +	ensure_not_expanded sparse-checkout set deep/deeper1 &&
>> +	ensure_not_expanded sparse-checkout set folder2 &&
>> +
>> +	# Demonstrate that the checks that "folder1/a" is a file
>> +	# do not cause a sparse-index expansion (since it is in the
>> +	# sparse-checkout cone).
>> +	echo >>sparse-index/folder2/a &&
>> +	git -C sparse-index add folder2/a &&
>> +
>> +	ensure_not_expanded sparse-checkout add folder1 &&
>> +
>> +	# Skip checks here, since deep/deeper1 is inside a sparse directory
>> +	# that must be expanded to check whether `deep/deeper1` is a file
>> +	# or not.
>> +	ensure_not_expanded sparse-checkout set --skip-checks deep/deeper1 &&
>> +	ensure_not_expanded sparse-checkout set
>> +'
>> +
> 
> These tests look good for ensuring sparsity is preserved, but it'd be nice
> to also have some "stress tests" of 'sparse-checkout (add|set)'. The purpose
> would be to make sure the index has the right contents for various types of
> pattern changes, e.g. running 'sparse-checkout (add|set) <path>', then
> verifying index contents with 'ls-files --sparse'. Paths might be:
> 
> - in vs. out of (current) cone
> - match an existing vs. nonexistent directory
> 
> etc.

I guess I was relying on tests added previously for the sparse index,
such as this one:

test_expect_success 'sparse-index contents' '
	init_repos &&

	git -C sparse-index ls-files --sparse --stage >cache &&
	for dir in folder1 folder2 x
	do
		TREE=$(git -C sparse-index rev-parse HEAD:$dir) &&
		grep "040000 $TREE 0	$dir/" cache \
			|| return 1
	done &&

	git -C sparse-index sparse-checkout set folder1 &&

	git -C sparse-index ls-files --sparse --stage >cache &&
	for dir in deep folder2 x
	do
		TREE=$(git -C sparse-index rev-parse HEAD:$dir) &&
		grep "040000 $TREE 0	$dir/" cache \
			|| return 1
	done &&

	git -C sparse-index sparse-checkout set deep/deeper1 &&

	git -C sparse-index ls-files --sparse --stage >cache &&
	for dir in deep/deeper2 folder1 folder2 x
	do
		TREE=$(git -C sparse-index rev-parse HEAD:$dir) &&
		grep "040000 $TREE 0	$dir/" cache \
			|| return 1
	done &&

	# Disabling the sparse-index replaces tree entries with full ones
	git -C sparse-index sparse-checkout init --no-sparse-index &&
	test_sparse_match git ls-files --stage --sparse
'

But this test isn't covering enough interesting cases that might
cause issues with the changes in this series. I'll add a patch that
increases coverage in this area.

Thanks,
-Stolee