[1/1] sparse-checkout: list folders in cone mode

Commit Message

Johannes Schindelin via GitGitGadget Dec. 26, 2019, 8:49 p.m. UTC

From: Derrick Stolee <[e-mail]>

When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set'
command taks a list of folders as input, then creates an ordered
list of sparse-checkout patterns such that those folders are
recursively included and all sibling blobs along the parent folders
are also included. Listing the patterns is less user-friendly than the
folders themselves.

In cone mode, and as long as the patterns match the expected cone-mode
pattern types, change the output of 'git sparse-checkout list' to only
show the folders that created the patterns.

With this change, the following piped commands would not change the
working directory:

	git sparse-checkout list | git sparse-checkout set --stdin

The only time this would not work is if core.sparseCheckoutCone is
true, but the sparse-checkout file contains patterns that do not
match the expected pattern types for cone mode.

Signed-off-by: Derrick Stolee <[e-mail]>
---
 Documentation/git-sparse-checkout.txt | 11 ++++++++++-
 builtin/sparse-checkout.c             | 21 +++++++++++++++++++++
 t/t1091-sparse-checkout-builtin.sh    | 11 +++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

Comments

Junio C Hamano Dec. 26, 2019, 9:17 p.m. UTC | #1

"Derrick Stolee via GitGitGadget" <[e-mail]> writes:

> From: Derrick Stolee <[e-mail]>

> Subject: Re: [PATCH 1/1] sparse-checkout: list folders in cone mode
s/folder/directory/ everywhere as the rest of Git.

> When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set'
> command taks a list of folders as input, then creates an ordered

"takes"

> list of sparse-checkout patterns such that those folders are
> recursively included and all sibling blobs along the parent folders

In this sentence, what does a "blob" really mean?  Do you mean a
filesystem entity, that is not a folder, that is immediately
contained in the "parent folder" (in other words, regular files
and symbolic links)?

How would this interact with a submodule by the way?

> are also included. Listing the patterns is less user-friendly than the
> folders themselves.
>
> In cone mode, and as long as the patterns match the expected cone-mode
> pattern types, change the output of 'git sparse-checkout list' to only
> show the folders that created the patterns.
> ...
> +In the cone mode case, the `git sparse-checkout list` subcommand will list the
> +folders that define the recursive patterns. For the example sparse-checkout file
> +above, the output is as follows:
> +
> +--------------------------
> +$ git sparse-checkout list
> +A/B/C
> +--------------------------
> +

Sounds like a worthwhile usability improvement.

Derrick Stolee Dec. 27, 2019, 2:05 p.m. UTC | #2

On 12/26/2019 4:17 PM, Junio C Hamano wrote:
> "Derrick Stolee via GitGitGadget" <[e-mail]> writes:
> 
>> From: Derrick Stolee <[e-mail]>
> 
>> Subject: Re: [PATCH 1/1] sparse-checkout: list folders in cone mode
> s/folder/directory/ everywhere as the rest of Git.
> 
>> When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set'
>> command taks a list of folders as input, then creates an ordered
> 
> "takes"

Good catch.

>> list of sparse-checkout patterns such that those folders are
>> recursively included and all sibling blobs along the parent folders
> 
> In this sentence, what does a "blob" really mean?  Do you mean a
> filesystem entity, that is not a folder, that is immediately
> contained in the "parent folder" (in other words, regular files
> and symbolic links)?

You're right, I'm using strange wording here. How about "sibling
entries"?

> How would this interact with a submodule by the way?

I just checked with the Git repo by running:

	git submodule init
	git submodule update
	git sparse-checkout init --cone

The working directory then contains all blobs at root AND the
sha1collisiondetection submodule. Interesting that the sparse-
checkout feature ignores submodules. That seems like the best
approach since the user can already enlist in a subset of the
submodules.

>> are also included. Listing the patterns is less user-friendly than the
>> folders themselves.
>>
>> In cone mode, and as long as the patterns match the expected cone-mode
>> pattern types, change the output of 'git sparse-checkout list' to only
>> show the folders that created the patterns.
>> ...
>> +In the cone mode case, the `git sparse-checkout list` subcommand will list the
>> +folders that define the recursive patterns. For the example sparse-checkout file
>> +above, the output is as follows:
>> +
>> +--------------------------
>> +$ git sparse-checkout list
>> +A/B/C
>> +--------------------------
>> +
> 
> Sounds like a worthwhile usability improvement.
 
Thanks,
-Stolee

Elijah Newren Dec. 27, 2019, 3:52 p.m. UTC | #3

On Thu, Dec 26, 2019 at 12:49 PM Derrick Stolee via GitGitGadget
<[e-mail]> wrote:
>
> From: Derrick Stolee <[e-mail]>
>
> When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set'
> command taks a list of folders as input, then creates an ordered
> list of sparse-checkout patterns such that those folders are
> recursively included and all sibling blobs along the parent folders
> are also included. Listing the patterns is less user-friendly than the
> folders themselves.

I didn't spot anything that Junio hasn't already mentioned, but I'm
just chiming in to say that this sounds good and thanks so much for
working on the sparse-checkout command.  :-)

Patch

diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
index 9c3c66cc37..dcca9ee826 100644
--- a/Documentation/git-sparse-checkout.txt
+++ b/Documentation/git-sparse-checkout.txt
@@ -28,7 +28,7 @@  THE FUTURE.
 COMMANDS
 --------
 'list'::
-	Provide a list of the contents in the sparse-checkout file.
+	Describe the patterns in the sparse-checkout file.
 
 'init'::
 	Enable the `core.sparseCheckout` setting. If the
@@ -150,6 +150,15 @@  expecting patterns of these types. Git will warn if the patterns do not match.
 If the patterns do match the expected format, then Git will use faster hash-
 based algorithms to compute inclusion in the sparse-checkout.
 
+In the cone mode case, the `git sparse-checkout list` subcommand will list the
+folders that define the recursive patterns. For the example sparse-checkout file
+above, the output is as follows:
+
+--------------------------
+$ git sparse-checkout list
+A/B/C
+--------------------------
+
 If `core.ignoreCase=true`, then the pattern-matching algorithm will use a
 case-insensitive check. This corrects for case mismatched filenames in the
 'git sparse-checkout set' command to reflect the expected cone in the working
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 5d62f7a66d..b3bed891cb 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -53,6 +53,8 @@  static int sparse_checkout_list(int argc, const char **argv)
 
 	memset(&pl, 0, sizeof(pl));
 
+	pl.use_cone_patterns = core_sparse_checkout_cone;
+
 	sparse_filename = get_sparse_checkout_filename();
 	res = add_patterns_from_file_to_list(sparse_filename, "", 0, &pl, NULL);
 	free(sparse_filename);
@@ -62,6 +64,25 @@  static int sparse_checkout_list(int argc, const char **argv)
 		return 0;
 	}
 
+	if (pl.use_cone_patterns) {
+		int i;
+		struct pattern_entry *pe;
+		struct hashmap_iter iter;
+		struct string_list sl = STRING_LIST_INIT_DUP;
+
+		hashmap_for_each_entry(&pl.recursive_hashmap, &iter, pe, ent) {
+			/* pe->pattern starts with "/", skip it */
+			string_list_insert(&sl, pe->pattern + 1);
+		}
+
+		string_list_sort(&sl);
+
+		for (i = 0; i < sl.nr; i++)
+			printf("%s\n", sl.items[i].string);
+
+		return 0;
+	}
+
 	write_patterns_to_file(stdout, &pl);
 	clear_pattern_list(&pl);
 
diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index 6f7e2d0c9e..37f6d8fa90 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -246,6 +246,17 @@  test_expect_success 'cone mode: init and set' '
 	test_cmp expect dir
 '
 
+test_expect_success 'cone mode: list' '
+	cat >expect <<-EOF &&
+		folder1
+		folder2
+	EOF
+	git -C repo sparse-checkout set --stdin <expect &&
+	git -C repo sparse-checkout list >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp expect actual
+'
+
 test_expect_success 'cone mode: set with nested folders' '
 	git -C repo sparse-checkout set deep deep/deeper1/deepest 2>err &&
 	test_line_count = 0 err &&