sparse-checkout: set worktree-config correctly

`git sparse-checkout set/init` enables worktree-specific
configuration[*] by setting extensions.worktreeConfig=true, but neglects
to perform the additional necessary bookkeeping of relocating
`core.bare=true` and `core.worktree` from $GIT_COMMON_DIR/config to
$GIT_COMMON_DIR/config.worktree, as documented in git-worktree.txt. As a
result of this oversight, these settings, which are nonsensical for
secondary worktrees, can cause Git commands to incorrectly consider a
worktree bare (in the case of `core.bare`) or operate on the wrong
worktree (in the case of `core.worktree`). Fix this problem by taking
advantage of the recently-added init_worktree_config() which enables
`extensions.worktreeConfig` and takes care of necessary bookkeeping.

While at it, for backward-compatibility reasons, also stop upgrading the
repository format to "1" since doing so is (unintentionally) not
required to take advantage of `extensions.worktreeConfig`, as explained
by 11664196ac ("Revert "check_repository_format_gently(): refuse
extensions for old repositories"", 2020-07-15).

[*] The main reason to use worktree-specific config for the
sparse-checkout builtin was to avoid enabling sparse-checkout patterns
in one and causing a loss of files in another. If a worktree does not
have a sparse-checkout patterns file, then the sparse-checkout logic
will not kick in on that worktree.

Reported-by: Sean Allred <allred.sean@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 13 insertions, 15 deletions

diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 679c107036..314c8d61f8 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -15,6 +15,7 @@
 #include "wt-status.h"
 #include "quote.h"
 #include "sparse-index.h"
+#include "worktree.h"
 
 static const char *empty_base = "";
 
@@ -359,26 +360,23 @@ enum sparse_checkout_mode {
 
 static int set_config(enum sparse_checkout_mode mode)
 {
-	const char *config_path;
-
-	if (upgrade_repository_format(1) < 0)
-		die(_("unable to upgrade repository format to enable worktreeConfig"));
-	if (git_config_set_gently("extensions.worktreeConfig", "true")) {
-		error(_("failed to set extensions.worktreeConfig setting"));
+	/* Update to use worktree config, if not already. */
+	if (init_worktree_config(the_repository)) {
+		error(_("failed to initialize worktree config"));
 		return 1;
 	}
 
-	config_path = git_path("config.worktree");
-	git_config_set_in_file_gently(config_path,
-				      "core.sparseCheckout",
-				      mode ? "true" : NULL);
-
-	git_config_set_in_file_gently(config_path,
-				      "core.sparseCheckoutCone",
-				      mode == MODE_CONE_PATTERNS ? "true" : NULL);
+	if (repo_config_set_worktree_gently(the_repository,
+					    "core.sparseCheckout",
+					    mode ? "true" : "false") ||
+	    repo_config_set_worktree_gently(the_repository,
+					    "core.sparseCheckoutCone",
+					    mode == MODE_CONE_PATTERNS ?
+						"true" : "false"))
+		return 1;
 
 	if (mode == MODE_NO_PATTERNS)
-		set_sparse_index_config(the_repository, 0);
+		return set_sparse_index_config(the_repository, 0);
 
 	return 0;
 }