Thread (10 messages) flat view 10 messages, 3 authors, 2021-09-21

Re: [PATCH 2/3] sparse-checkout: clear patterns when switching modes

From: Taylor Blau <hidden>
Date: 2021-09-21 02:57:57

On Mon, Sep 20, 2021 at 05:57:37PM +0000, Derrick Stolee via GitGitGadget wrote:
quoted hunk ↗ jump to hunk
From: Derrick Stolee <redacted>

Previously, when a user runs 'git sparse-checkout init --cone', the
existing patterns would remain, even if the patterns were not in cone
mode. This causes confusion as to how the patterns should work when
later 'git sparse-checkout add' commands append to the pattern list.

In fact, the way these patterns were modified was not even a strict
appending of patterns, but mutating and reordering patterns because of
how the paths were interpreted and rewritten.

As a first step, we shall start overwriting the pattern set completely
when switching to cone mode, unless the existing patterns already match
cone mode patterns. The 'use_cone_patterns' member is set to false if
the patterns fail to parse using cone mode restrictions.

Signed-off-by: Derrick Stolee <redacted>
---
 builtin/sparse-checkout.c          | 13 +++++++++++--
 t/t1091-sparse-checkout-builtin.sh |  9 ++++++++-
 2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index b45fd97a98b..fe76c3eedda 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -348,8 +348,17 @@ static int sparse_checkout_init(int argc, const char **argv)

 	/* If we already have a sparse-checkout file, use it. */
 	if (res >= 0) {
-		free(sparse_filename);
-		return update_working_directory(NULL);
+		if (pl.use_cone_patterns || !init_opts.cone_mode) {
I traced through this code beginning with sparse_checkout_init() and
right before the check on pl.use_cone_patterns, and I couldn't find
anywhere that this variable is set to a non-zero value. Could you let me
know if I'm missing something, or is the left-hand side of this or
redundant?

I guess what this check wants to be saying is "if the existing
sparse-checkout was in cone mode or we are transitioning to cone mode,
then quit now".
+			free(sparse_filename);
+			return update_working_directory(NULL);
+		}
+
+		/*
+		 * At this point, note that if res >= 0 but pl.use_cone_patterns
+		 * is false, then we want to override the patterns with the
+		 * initial set of cone mode patterns.
+		 */
+		clear_pattern_list(&pl);
...or otherwise, we are transitioning into cone mode from a non-cone
mode state?

If so, this may be somewhat surprising to users who have their patterns
cleared after re-initializing. I guess the command is called "init", but
it may be friendlier to have a `--reinitialize` option or similar which
indicates the user's preference to obliterate existing patterns if
necessary.

See my message at [1] for some more details about a possible suggestion
there.
quoted hunk ↗ jump to hunk
 	}

 	if (get_oid("HEAD", &oid)) {
diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index a429d2cc671..af0acd32bd9 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -108,7 +108,14 @@ test_expect_success 'switching to cone mode with non-cone mode patterns' '
 	git -C bad-patterns sparse-checkout init &&
 	git -C bad-patterns sparse-checkout add dir &&
 	git -C bad-patterns config core.sparseCheckoutCone true &&
-	git -C bad-patterns sparse-checkout add dir
+	git -C bad-patterns sparse-checkout add dir &&
+
+	git -C bad-patterns sparse-checkout init --cone &&
+	cat >expect <<-\EOF &&
+	/*
+	!/*/
+	EOF
+	test_cmp expect bad-patterns/.git/info/sparse-checkout

Makes sense that we have to look at the contents of
$GIT_DIR/info/sparse-checkout directly here to see the explicit '/*' and
'!/*/' patterns.

Thanks,
Taylor

[1]: https://lore.kernel.org/git/YUi55%2F3L9nizTVyA@nand.local/ (local)
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