[PATCH v2 04/11] sparse-checkout: 'set' subcommand

["Derrick Stolee via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>

The 'git sparse-checkout set' subcommand takes a list of patterns
as arguments and writes them to the sparse-checkout file. Then, it
updates the working directory using 'git read-tree -mu HEAD'.

The 'set' subcommand will replace the entire contents of the
sparse-checkout file. The write_patterns_and_update() method is
extracted from cmd_sparse_checkout() to make it easier to implement
'add' and/or 'remove' subcommands in the future.

Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
 Documentation/git-sparse-checkout.txt |  5 +++++
 builtin/sparse-checkout.c             | 31 ++++++++++++++++++++++++++-
 t/t1091-sparse-checkout-builtin.sh    | 19 ++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
index 9707ef93b1..87813e5797 100644
--- a/Documentation/git-sparse-checkout.txt
+++ b/Documentation/git-sparse-checkout.txt
@@ -34,6 +34,11 @@ COMMANDS
 	by Git. Add patterns to the sparse-checkout file to
 	repopulate the working directory.
 
+'set'::
+	Write a set of patterns to the sparse-checkout file, as given as
+	a list of arguments following the 'set' subcommand. Update the
+	working directory to match the new patterns.
+
 SPARSE CHECKOUT
 ----------------
 
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 656e6ebdd5..13333fba6a 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -8,7 +8,7 @@
 #include "strbuf.h"
 
 static char const * const builtin_sparse_checkout_usage[] = {
-	N_("git sparse-checkout [init|list]"),
+	N_("git sparse-checkout [init|list|set] <options>"),
 	NULL
 };
 
@@ -130,6 +130,33 @@ static int sparse_checkout_init(int argc, const char **argv)
 	return update_working_directory();
 }
 
+static int write_patterns_and_update(struct pattern_list *pl)
+{
+	char *sparse_filename;
+	FILE *fp;
+
+	sparse_filename = get_sparse_checkout_filename();
+	fp = fopen(sparse_filename, "w");
+	write_patterns_to_file(fp, pl);
+	fclose(fp);
+	free(sparse_filename);
+
+	clear_pattern_list(pl);
+	return update_working_directory();
+}
+
+static int sparse_checkout_set(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	struct pattern_list pl;
+	memset(&pl, 0, sizeof(pl));
+
+	for (i = 1; i < argc; i++)
+		add_pattern(argv[i], NULL, 0, &pl, 0);
+
+	return write_patterns_and_update(&pl);
+}
+
 int cmd_sparse_checkout(int argc, const char **argv, const char *prefix)
 {
 	static struct option builtin_sparse_checkout_options[] = {
@@ -152,6 +179,8 @@ int cmd_sparse_checkout(int argc, const char **argv, const char *prefix)
 			return sparse_checkout_list(argc, argv);
 		if (!strcmp(argv[0], "init"))
 			return sparse_checkout_init(argc, argv);
+		if (!strcmp(argv[0], "set"))
+			return sparse_checkout_set(argc, argv, prefix);
 	}
 
 	usage_with_options(builtin_sparse_checkout_usage,
diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index 26b4ce9acd..f21ea61494 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -101,5 +101,24 @@ test_expect_success 'clone --sparse' '
 	test_cmp expect dir
 '
 
+test_expect_success 'set sparse-checkout using builtin' '
+	git -C repo sparse-checkout set "/*" "!/*/" "*folder*" &&
+	cat >expect <<-EOF &&
+		/*
+		!/*/
+		*folder*
+	EOF
+	git -C repo sparse-checkout list >actual &&
+	test_cmp expect actual &&
+	test_cmp expect repo/.git/info/sparse-checkout &&
+	ls repo >dir  &&
+	cat >expect <<-EOF &&
+		a
+		folder1
+		folder2
+	EOF
+	test_cmp expect dir
+'
+
 test_done
 
-- 
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