[PATCH v2 0/2] environment: move excludes_file into repo_config_values

[PATCH v2 0/2] environment: move excludes_file into repo_config_values

[Tian Yuchen]

This series continues the libification effort by migrating the global
string variable 'excludes_file' into 'struct repo_config_values'. Since
this is a dynamically allocated variable, the migration requires proper
heap memory management.

The series is structured in two commits:

 - Abstract the XDG fallback lazy-loading logic out of dir.c into a proper
getter.

 - Move the variables into the struct and introduce 'repo_config_values_clear()'.

Note on Submodules: A temporary shield 'if (repo != the_repository)' is
included in both the getter and the clear function. This prevents
uninitialized submodules from triggering the BUG() assertion.
(Inspiration: [1])

Changes since V1:

 - fix a typo in the second commit.

 - initialize excludes_file to NULL in repo_config_values_init().

 - call FREE_AND_NULL() to free attributes_file as well in
 repo_config_values_clear().

Thanks!

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Mentored-by: Olamide Caleb Bello <belkid98@gmail.com>
Signed-off-by: Tian Yuchen <cat@malon.dev>

[1] https://lore.kernel.org/git/c95a7730-7b14-4be0-a4e4-861b2f5430ea@gmail.com/

Tian Yuchen (2):
  dir: encapsulate excludes_file lazy-load
  environment: move excludes_file into repo_config_values

 dir.c         |  4 ++--
 environment.c | 32 +++++++++++++++++++++++++++++---
 environment.h | 13 ++++++++++++-
 repository.c  |  1 +
 4 files changed, 44 insertions(+), 6 deletions(-)

-- 
2.43.0

[PATCH v2 1/2] dir: encapsulate excludes_file lazy-load

[Tian Yuchen]

The global variable 'excludes_file' is used to track the path to the
global ignore file, 'core.excludesfile'. If this variable is NULL,
setup_standard_excludes() in dir.c forcefully evaluates and assigns
the XDG default path to it.

Introduce repo_excludes_file() as a getter to encapsulate this
lazy-loading logic. This prepares the variable to be safely moved
into 'struct repo_config_values' in the subsequent commit.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Mentored-by: Olamide Caleb Bello <belkid98@gmail.com>
Signed-off-by: Tian Yuchen <cat@malon.dev>
---
 dir.c         | 4 ++--
 environment.c | 7 +++++++
 environment.h | 5 +++++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/dir.c b/dir.c
index 7a73690fbc..4f87a52b3c 100644
--- a/dir.c
+++ b/dir.c
@@ -3481,11 +3481,11 @@ static GIT_PATH_FUNC(git_path_info_exclude, "info/exclude")
 
 void setup_standard_excludes(struct dir_struct *dir)
 {
+	const char *excludes_file = repo_excludes_file(the_repository);
+
 	dir->exclude_per_dir = ".gitignore";
 
 	/* core.excludesfile defaulting to $XDG_CONFIG_HOME/git/ignore */
-	if (!excludes_file)
-		excludes_file = xdg_config_home("ignore");
 	if (excludes_file && !access_or_warn(excludes_file, R_OK, 0))
 		add_patterns_from_file_1(dir, excludes_file,
 					 dir->untracked ? &dir->internal.ss_excludes_file : NULL);
diff --git a/environment.c b/environment.c
index ba2c60103f..8efcaeafa6 100644
--- a/environment.c
+++ b/environment.c
@@ -134,6 +134,13 @@ int is_bare_repository(void)
 	return is_bare_repository_cfg && !repo_get_work_tree(the_repository);
 }
 
+const char *repo_excludes_file(struct repository *repo)
+{
+	if (!excludes_file)
+		excludes_file = xdg_config_home("ignore");
+	return excludes_file;
+}
+
 int have_git_dir(void)
 {
 	return startup_info->have_repository
diff --git a/environment.h b/environment.h
index 6f18286955..52d531e4ea 100644
--- a/environment.h
+++ b/environment.h
@@ -133,6 +133,11 @@ int git_default_config(const char *, const char *,
 int git_default_core_config(const char *var, const char *value,
 			    const struct config_context *ctx, void *cb);
 
+/*
+ * TODO: This still relies on the global state.
+ */
+const char *repo_excludes_file(struct repository *repo);
+
 void repo_config_values_init(struct repo_config_values *cfg);
 
 /*
-- 
2.43.0

[PATCH v2 2/2] environment: move excludes_file into repo_config_values

[Tian Yuchen]

Continue the libification effort by moving the 'excludes_file' global
variable into 'struct repo_config_values'.

Since 'excludes_file' is a dynamically allocated string (char *), it
requires proper memory management. Introduce repo_config_values_clear()
to safely free the heap memory when repository instance is destroyed.

Note:

 - 'if (repo != the_repository)' fallback logic is temporarily added
in both the getter and the clear function. This prevents calling
repo_config_values() on uninitialized submodules, which triggers BUG().

 - 'attribute_file' is another string variable that was migrated
 earlier. Its FREE_AND_NULL() call is also added to
 repo_config_values_clear().

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Mentored-by: Olamide Caleb Bello <belkid98@gmail.com>
Signed-off-by: Tian Yuchen <cat@malon.dev>
---
 environment.c | 31 +++++++++++++++++++++++++------
 environment.h | 14 ++++++++++----
 repository.c  |  1 +
 3 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/environment.c b/environment.c
index 8efcaeafa6..b8dfa3e213 100644
--- a/environment.c
+++ b/environment.c
@@ -57,7 +57,6 @@ enum fsync_method fsync_method = FSYNC_METHOD_DEFAULT;
 enum fsync_component fsync_components = FSYNC_COMPONENTS_DEFAULT;
 char *editor_program;
 char *askpass_program;
-char *excludes_file;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
 enum eol core_eol = EOL_UNSET;
 int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN;
@@ -136,9 +135,13 @@ int is_bare_repository(void)
 
 const char *repo_excludes_file(struct repository *repo)
 {
-	if (!excludes_file)
-		excludes_file = xdg_config_home("ignore");
-	return excludes_file;
+	if (!repo || !repo->initialized || repo != the_repository)
+		return NULL;
+
+	if (!repo_config_values(repo)->excludes_file)
+		repo_config_values(repo)->excludes_file = xdg_config_home("ignore");
+
+	return repo_config_values(repo)->excludes_file;
 }
 
 int have_git_dir(void)
@@ -468,8 +471,8 @@ int git_default_core_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "core.excludesfile")) {
-		FREE_AND_NULL(excludes_file);
-		return git_config_pathname(&excludes_file, var, value);
+		FREE_AND_NULL(cfg->excludes_file);
+		return git_config_pathname(&cfg->excludes_file, var, value);
 	}
 
 	if (!strcmp(var, "core.whitespace")) {
@@ -722,6 +725,7 @@ int git_default_config(const char *var, const char *value,
 void repo_config_values_init(struct repo_config_values *cfg)
 {
 	cfg->attributes_file = NULL;
+	cfg->excludes_file = NULL;
 	cfg->apply_sparse_checkout = 0;
 	cfg->branch_track = BRANCH_TRACK_REMOTE;
 	cfg->trust_ctime = 1;
@@ -733,3 +737,18 @@ void repo_config_values_init(struct repo_config_values *cfg)
 	cfg->sparse_expect_files_outside_of_patterns = 0;
 	cfg->warn_on_object_refname_ambiguity = 1;
 }
+
+void repo_config_values_clear(struct repository *repo)
+{
+	struct repo_config_values *cfg;
+
+	if (repo != the_repository)
+		return;
+
+	cfg = repo_config_values(repo);
+	if (!cfg)
+		return;
+
+	FREE_AND_NULL(cfg->attributes_file);
+	FREE_AND_NULL(cfg->excludes_file);
+}
diff --git a/environment.h b/environment.h
index 52d531e4ea..2e8352de7f 100644
--- a/environment.h
+++ b/environment.h
@@ -90,6 +90,7 @@ struct repository;
 struct repo_config_values {
 	/* section "core" config values */
 	char *attributes_file;
+	char *excludes_file;
 	int apply_sparse_checkout;
 	int trust_ctime;
 	int check_stat;
@@ -133,13 +134,19 @@ int git_default_config(const char *, const char *,
 int git_default_core_config(const char *var, const char *value,
 			    const struct config_context *ctx, void *cb);
 
-/*
- * TODO: This still relies on the global state.
- */
 const char *repo_excludes_file(struct repository *repo);
 
 void repo_config_values_init(struct repo_config_values *cfg);
 
+/*
+ * Frees memory allocated for dynamically loaded configuration values
+ * inside `repo_config_values`.
+ *
+ * As dynamically allocated variables are migrated into this struct,
+ * their FREE_AND_NULL() calls should be appended here.
+ */
+void repo_config_values_clear(struct repository *repo);
+
 /*
  * TODO: All the below state either explicitly or implicitly relies on
  * `the_repository`. We should eventually get rid of these and make the
@@ -213,7 +220,6 @@ extern char *git_log_output_encoding;
 
 extern char *editor_program;
 extern char *askpass_program;
-extern char *excludes_file;
 
 /*
  * The character that begins a commented line in user-editable file
diff --git a/repository.c b/repository.c
index 187dd471c4..b31f1b7852 100644
--- a/repository.c
+++ b/repository.c
@@ -388,6 +388,7 @@ void repo_clear(struct repository *repo)
 	FREE_AND_NULL(repo->parsed_objects);
 
 	repo_settings_clear(repo);
+	repo_config_values_clear(repo);
 
 	if (repo->config) {
 		git_configset_clear(repo->config);
-- 
2.43.0