Subject: Re: [PATCH 17/20] sparse-checkout: disable sparse-index

From: SZEDER Gábor <[email-masked]>
Date: Sat, 27 Feb 2021 13:32:53 +0100

On Tue, Feb 23, 2021 at 08:14:26PM +0000, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <[email-masked]>
> 
> We use 'git sparse-checkout init --cone --sparse-index' to toggle the
> sparse-index feature. It makes sense to also disable it when running
> 'git sparse-checkout disable'. This is particularly important because it
> removes the extensions.sparseIndex config option, allowing other tools
> to use this Git repository again.
> 
> This does mean that 'git sparse-checkout init' will not re-enable the
> sparse-index feature, even if it was previously enabled.
> 
> While testing this feature, I noticed that the sparse-index was not
> being written on the first run, but by a second. This was caught by the
> call to 'test-tool read-cache --table'. This requires adjusting some
> assignments to core_apply_sparse_checkout and pl.use_cone_patterns in
> the sparse_checkout_init() logic.
> 
> Signed-off-by: Derrick Stolee <[email-masked]>
> ---
>  builtin/sparse-checkout.c          | 10 +++++++++-
>  t/t1091-sparse-checkout-builtin.sh | 13 +++++++++++++
>  2 files changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
> index ca63e2c64e95..585343fa1972 100644
> --- a/builtin/sparse-checkout.c
> +++ b/builtin/sparse-checkout.c
> @@ -280,6 +280,9 @@ static int set_config(enum sparse_checkout_mode mode)
>  				      "core.sparseCheckoutCone",
>  				      mode == MODE_CONE_PATTERNS ? "true" : NULL);
>  
> +	if (mode == MODE_NO_PATTERNS)
> +		set_sparse_index_config(the_repository, 0);
> +
>  	return 0;
>  }
>  
> @@ -341,10 +344,11 @@ static int sparse_checkout_init(int argc, const char **argv)
>  		the_repository->index->updated_workdir = 1;
>  	}
>  
> +	core_apply_sparse_checkout = 1;
> +
>  	/* If we already have a sparse-checkout file, use it. */
>  	if (res >= 0) {
>  		free(sparse_filename);
> -		core_apply_sparse_checkout = 1;
>  		return update_working_directory(NULL);
>  	}
>  
> @@ -366,6 +370,7 @@ static int sparse_checkout_init(int argc, const char **argv)
>  	add_pattern(strbuf_detach(&pattern, NULL), empty_base, 0, &pl, 0);
>  	strbuf_addstr(&pattern, "!/*/");
>  	add_pattern(strbuf_detach(&pattern, NULL), empty_base, 0, &pl, 0);
> +	pl.use_cone_patterns = init_opts.cone_mode;
>  
>  	return write_patterns_and_update(&pl);
>  }
> @@ -632,6 +637,9 @@ static int sparse_checkout_disable(int argc, const char **argv)
>  	strbuf_addstr(&match_all, "/*");
>  	add_pattern(strbuf_detach(&match_all, NULL), empty_base, 0, &pl, 0);
>  
> +	prepare_repo_settings(the_repository);
> +	the_repository->settings.sparse_index = 0;
> +
>  	if (update_working_directory(&pl))
>  		die(_("error while refreshing working directory"));
>  
> diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
> index fc64e9ed99f4..ff1ad570a255 100755
> --- a/t/t1091-sparse-checkout-builtin.sh
> +++ b/t/t1091-sparse-checkout-builtin.sh
> @@ -205,6 +205,19 @@ test_expect_success 'sparse-checkout disable' '
>  	check_files repo a deep folder1 folder2
>  '
>  
> +test_expect_success 'sparse-index enabled and disabled' '
> +	git -C repo sparse-checkout init --cone --sparse-index &&
> +	test_cmp_config -C repo true extensions.sparseIndex &&
> +	test-tool -C repo read-cache --table >cache &&
> +	grep " tree " cache &&
> +
> +	git -C repo sparse-checkout disable &&
> +	test-tool -C repo read-cache --table >cache &&
> +	! grep " tree " cache &&
> +	git -C repo config --list >config &&
> +	! grep extensions.sparseindex config
> +'

This test passes with GIT_TEST_SPLIT_INDEX=1 at the moment, because,
unfortunately, GIT_TEST_SPLIT_INDEX has been broken for the past two
years.  However, if I run it with my WIP fixes for that issue [1],
then it will fail:

  +git -C repo sparse-checkout init --cone --sparse-index
  +test_cmp_config -C repo true extensions.sparseIndex
  +test-tool -C repo read-cache --table
  +grep  tree  cache
  error: last command exited with $?=1
  not ok 16 - sparse-index enabled and disabled

https://travis-ci.com/github/szeder/git-cooking-topics-for-travis-ci/jobs/486702444#L2594

[1] Try to run it with:

      https://github.com/szeder/git split-index-fixes

    The code is, I believe, close to final, the commit messages,
    however, are far from being finished.

> +
>  test_expect_success 'cone mode: init and set' '
>  	git -C repo sparse-checkout init --cone &&
>  	git -C repo config --list >config &&
> -- 
> gitgitgadget
>