environment: consolidate config values

The config values parsed in `git_default_config()` are loaded eagerly
and stored in global variables. Storing these values in global variables
can lead to unexpected behaviours when more than one Git repository run
in the same Git process.

Move these values into a `struct config_values` which can be accessed per
repository. This centralization will be important in moving other
variables and this will prevent us from moving any code from
`git_default_config()`, ensuring the current behaviour remains the same
while also enabling the libification of Git.
It is important to note that `git_default_config()` is a wrapper to other
`git_default_*_config()` such as `git_default_core_config()`.
Therefore to access and substitute some of these global variables,
the change has to be made in the functions themselves which parse and
store the values in the global variables.
This commit consolidates the variables `git_attributes_file` and
`core_apply_sparse_checkout` as an initial effort for subsequent
relocations.

Suggested-by: Phillip Wood <phillip.wood123@gmail.com>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Usman Akinyemi <usmanakinyemi202@gmail.com>
Signed-off-by: Olamide Caleb Bello <belkid98@gmail.com>

Author: cloobTech

attr.c

@@ -881,10 +881,12 @@ const char *git_attr_system_file(void)
 
 const char *git_attr_global_file(void)
 {
-	if (!git_attributes_file)
-		git_attributes_file = xdg_config_home("attributes");
+	struct config_values *cfg = the_repository->cfg_values;
 
-	return git_attributes_file;
+	if (!cfg->attributes_file_path)
+		cfg->attributes_file_path = xdg_config_home("attributes");
+
+	return cfg->attributes_file_path;
 }
 
 int git_attr_system_is_enabled(void)

builtin/backfill.c

@@ -1,4 +1,3 @@
-/* We need this macro to access core_apply_sparse_checkout */
 #define USE_THE_REPOSITORY_VARIABLE
 
 #include "builtin.h"
@@ -139,7 +138,7 @@ int cmd_backfill(int argc, const char **argv, const char *prefix, struct reposit
 	repo_config(repo, git_default_config, NULL);
 
 	if (ctx.sparse < 0)
-		ctx.sparse = core_apply_sparse_checkout;
+		ctx.sparse = repo->cfg_values->sparse_checkout;
 
 	result = do_backfill(&ctx);
 	backfill_context_clear(&ctx);

builtin/clone.c

@@ -623,7 +623,7 @@ static int git_sparse_checkout_init(const char *repo)
 	 * We must apply the setting in the current process
 	 * for the later checkout to use the sparse-checkout file.
 	 */
-	core_apply_sparse_checkout = 1;
+	the_repository->cfg_values->sparse_checkout = 1;
 
 	cmd.git_cmd = 1;
 	if (run_command(&cmd)) {

builtin/mv.c

@@ -572,7 +572,7 @@ int cmd_mv(int argc,
 		rename_index_entry_at(the_repository->index, pos, dst);
 
 		if (ignore_sparse &&
-		    core_apply_sparse_checkout &&
+			the_repository->cfg_values->sparse_checkout &&
 		    core_sparse_checkout_cone) {
 			/*
 			 * NEEDSWORK: we are *not* paying attention to

builtin/sparse-checkout.c

@@ -63,7 +63,7 @@ static int sparse_checkout_list(int argc, const char **argv, const char *prefix,
 	int res;
 
 	setup_work_tree();
-	if (!core_apply_sparse_checkout)
+	if (!the_repository->cfg_values->sparse_checkout)
 		die(_("this worktree is not sparse"));
 
 	argc = parse_options(argc, argv, prefix,
@@ -400,11 +400,11 @@ static int set_config(struct repository *repo,
 
 static enum sparse_checkout_mode update_cone_mode(int *cone_mode) {
 	/* If not specified, use previous definition of cone mode */
-	if (*cone_mode == -1 && core_apply_sparse_checkout)
+	if (*cone_mode == -1 && the_repository->cfg_values->sparse_checkout)
 		*cone_mode = core_sparse_checkout_cone;
 
 	/* Set cone/non-cone mode appropriately */
-	core_apply_sparse_checkout = 1;
+	the_repository->cfg_values->sparse_checkout = 1;
 	if (*cone_mode == 1 || *cone_mode == -1) {
 		core_sparse_checkout_cone = 1;
 		return MODE_CONE_PATTERNS;
@@ -418,7 +418,7 @@ static int update_modes(struct repository *repo, int *cone_mode, int *sparse_ind
 	int mode, record_mode;
 
 	/* Determine if we need to record the mode; ensure sparse checkout on */
-	record_mode = (*cone_mode != -1) || !core_apply_sparse_checkout;
+	record_mode = (*cone_mode != -1) || !repo->cfg_values->sparse_checkout;
 
 	mode = update_cone_mode(cone_mode);
 	if (record_mode && set_config(repo, mode))
@@ -699,9 +699,9 @@ static int modify_pattern_list(struct repository *repo,
 		break;
 	}
 
-	if (!core_apply_sparse_checkout) {
+	if (!repo->cfg_values->sparse_checkout) {
 		set_config(repo, MODE_ALL_PATTERNS);
-		core_apply_sparse_checkout = 1;
+		repo->cfg_values->sparse_checkout = 1;
 		changed_config = 1;
 	}
 
@@ -798,7 +798,7 @@ static int sparse_checkout_add(int argc, const char **argv, const char *prefix,
 	int ret;
 
 	setup_work_tree();
-	if (!core_apply_sparse_checkout)
+	if (!repo->cfg_values->sparse_checkout)
 		die(_("no sparse-checkout to add to"));
 
 	repo_read_index(repo);
@@ -907,7 +907,7 @@ static int sparse_checkout_reapply(int argc, const char **argv,
 	};
 
 	setup_work_tree();
-	if (!core_apply_sparse_checkout)
+	if (!repo->cfg_values->sparse_checkout)
 		die(_("must be in a sparse-checkout to reapply sparsity patterns"));
 
 	reapply_opts.cone_mode = -1;
@@ -969,7 +969,7 @@ static int sparse_checkout_clean(int argc, const char **argv,
 	};
 
 	setup_work_tree();
-	if (!core_apply_sparse_checkout)
+	if (!repo->cfg_values->sparse_checkout)
 		die(_("must be in a sparse-checkout to clean directories"));
 	if (!core_sparse_checkout_cone)
 		die(_("must be in a cone-mode sparse-checkout to clean directories"));
@@ -1035,7 +1035,7 @@ static int sparse_checkout_disable(int argc, const char **argv,
 	struct pattern_list pl;
 
 	/*
-	 * We do not exit early if !core_apply_sparse_checkout; due to the
+	 * We do not exit early if !repo->cfg_values->sparse_checkout; due to the
 	 * ability for users to manually muck things up between
 	 *   direct editing of .git/info/sparse-checkout
 	 *   running read-tree -m u HEAD or update-index --skip-worktree
@@ -1061,7 +1061,7 @@ static int sparse_checkout_disable(int argc, const char **argv,
 	hashmap_init(&pl.recursive_hashmap, pl_hashmap_cmp, NULL, 0);
 	hashmap_init(&pl.parent_hashmap, pl_hashmap_cmp, NULL, 0);
 	pl.use_cone_patterns = 0;
-	core_apply_sparse_checkout = 1;
+	repo->cfg_values->sparse_checkout = 1;
 
 	add_pattern("/*", empty_base, 0, &pl, 0);
 

builtin/worktree.c

@@ -536,7 +536,7 @@ static int add_worktree(const char *path, const char *refname,
 	 * If the current worktree has sparse-checkout enabled, then copy
 	 * the sparse-checkout patterns from the current worktree.
 	 */
-	if (core_apply_sparse_checkout)
+	if (the_repository->cfg_values->sparse_checkout)
 		copy_sparse_checkout(sb_repo.buf);
 
 	/*

config.c

@@ -1761,6 +1761,11 @@ static int config_set_element_cmp(const void *cmp_data UNUSED,
 	return strcmp(e1->key, e2->key);
 }
 
+void config_values_clear(struct config_values *cfg)
+{
+	free(cfg->attributes_file_path);
+}
+
 void git_configset_init(struct config_set *set)
 {
 	hashmap_init(&set->config_hash, config_set_element_cmp, NULL, 0);

config.h

@@ -135,6 +135,14 @@ struct config_context {
 	/* Config source metadata for key and value. */
 	const struct key_value_info *kvi;
 };
+
+/* Holds default config values */
+struct config_values {
+	/* core config values */
+	char *attributes_file_path;
+	int sparse_checkout;
+
+};
 #define CONFIG_CONTEXT_INIT { 0 }
 
 /**
@@ -187,6 +195,7 @@ int git_config_from_blob_oid(config_fn_t fn, const char *name,
 void git_config_push_parameter(const char *text);
 void git_config_push_env(const char *spec);
 int git_config_from_parameters(config_fn_t fn, void *data);
+void config_values_clear(struct config_values *cfg);
 
 /*
  * Read config when the Git directory has not yet been set up. In case

dir.c

@@ -1551,7 +1551,7 @@ enum pattern_match_result path_matches_pattern_list(
 
 int init_sparse_checkout_patterns(struct index_state *istate)
 {
-	if (!core_apply_sparse_checkout)
+	if (!istate->repo->cfg_values->sparse_checkout)
 		return 1;
 	if (istate->sparse_checkout_patterns)
 		return 0;

environment.c

@@ -53,7 +53,6 @@ char *git_commit_encoding;
 char *git_log_output_encoding;
 char *apply_default_whitespace;
 char *apply_default_ignorewhitespace;
-char *git_attributes_file;
 int zlib_compression_level = Z_BEST_SPEED;
 int pack_compression_level = Z_DEFAULT_COMPRESSION;
 int fsync_object_files = -1;
@@ -75,7 +74,6 @@ enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED;
 #endif
 enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 int grafts_keep_true_parents;
-int core_apply_sparse_checkout;
 int core_sparse_checkout_cone;
 int sparse_expect_files_outside_of_patterns;
 int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
@@ -327,6 +325,8 @@ static enum fsync_component parse_fsync_components(const char *var, const char *
 static int git_default_core_config(const char *var, const char *value,
 				   const struct config_context *ctx, void *cb)
 {
+	struct config_values *cfg = the_repository->cfg_values;
+
 	/* This needs a better name */
 	if (!strcmp(var, "core.filemode")) {
 		trust_executable_bit = git_config_bool(var, value);
@@ -364,8 +364,8 @@ static int git_default_core_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "core.attributesfile")) {
-		FREE_AND_NULL(git_attributes_file);
-		return git_config_pathname(&git_attributes_file, var, value);
+		FREE_AND_NULL(cfg->attributes_file_path);
+		return git_config_pathname(&cfg->attributes_file_path, var, value);
 	}
 
 	if (!strcmp(var, "core.bare")) {
@@ -545,7 +545,7 @@ static int git_default_core_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "core.sparsecheckout")) {
-		core_apply_sparse_checkout = git_config_bool(var, value);
+		cfg->sparse_checkout = git_config_bool(var, value);
 		return 0;
 	}