environment: stop storing "core.logAllRefUpdates" globally

The value of "core.logAllRefUpdates" is being stored in the global
variable `log_all_ref_updates`. This design is somewhat aged nowadays,
where it is entirely possible to access multiple repositories in the
same process which all have different values for this setting. So using
a single global variable to track it is plain wrong.

Remove the global variable. Instead, we now provide a new function part
of the repo-settings subsystem that parses the value for a specific
repository. While that may require us to read the value multiple times,
we work around this by reading it once when the ref backends are set up
and caching the value there.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/checkout.c

@@ -951,6 +951,8 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
 	const char *old_desc, *reflog_msg;
 	if (opts->new_branch) {
 		if (opts->new_orphan_branch) {
+			enum log_refs_config log_all_ref_updates =
+				repo_settings_get_log_all_ref_updates(the_repository);
 			char *refname;
 
 			refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);

config.c

@@ -1452,16 +1452,6 @@ static int git_default_core_config(const char *var, const char *value,
 		return 0;
 	}
 
-	if (!strcmp(var, "core.logallrefupdates")) {
-		if (value && !strcasecmp(value, "always"))
-			log_all_ref_updates = LOG_REFS_ALWAYS;
-		else if (git_config_bool(var, value))
-			log_all_ref_updates = LOG_REFS_NORMAL;
-		else
-			log_all_ref_updates = LOG_REFS_NONE;
-		return 0;
-	}
-
 	if (!strcmp(var, "core.warnambiguousrefs")) {
 		warn_ambiguous_refs = git_config_bool(var, value);
 		return 0;

environment.c

@@ -77,7 +77,6 @@ int sparse_expect_files_outside_of_patterns;
 int merge_log_config = -1;
 int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
 unsigned long pack_size_limit_cfg;
-enum log_refs_config log_all_ref_updates = LOG_REFS_UNSET;
 int max_allowed_tree_depth =
 #ifdef _MSC_VER
 	/*

environment.h

@@ -181,8 +181,6 @@ extern int core_apply_sparse_checkout;
 extern int core_sparse_checkout_cone;
 extern int sparse_expect_files_outside_of_patterns;
 
-extern enum log_refs_config log_all_ref_updates;
-
 enum rebase_setup_type {
 	AUTOREBASE_NEVER = 0,
 	AUTOREBASE_LOCAL,

refs/files-backend.c

@@ -75,6 +75,7 @@ struct files_ref_store {
 	unsigned int store_flags;
 
 	char *gitcommondir;
+	enum log_refs_config log_all_ref_updates;
 
 	struct ref_cache *loose;
 
@@ -107,6 +108,7 @@ static struct ref_store *files_ref_store_init(struct repository *repo,
 	refs->gitcommondir = strbuf_detach(&sb, NULL);
 	refs->packed_ref_store =
 		packed_ref_store_init(repo, refs->gitcommondir, flags);
+	refs->log_all_ref_updates = repo_settings_get_log_all_ref_updates(repo);
 
 	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
 	chdir_notify_reparent("files-backend $GIT_COMMONDIR",
@@ -1704,7 +1706,7 @@ static int log_ref_setup(struct files_ref_store *refs,
 			 const char *refname, int force_create,
 			 int *logfd, struct strbuf *err)
 {
-	enum log_refs_config log_refs_cfg = log_all_ref_updates;
+	enum log_refs_config log_refs_cfg = refs->log_all_ref_updates;
 	struct strbuf logfile_sb = STRBUF_INIT;
 	char *logfile;
 

refs/reftable-backend.c

@@ -52,6 +52,7 @@ struct reftable_ref_store {
 	struct reftable_write_options write_options;
 
 	unsigned int store_flags;
+	enum log_refs_config log_all_ref_updates;
 	int err;
 };
 
@@ -157,21 +158,21 @@ static struct reftable_stack *stack_for(struct reftable_ref_store *store,
 	}
 }
 
-static int should_write_log(struct ref_store *refs, const char *refname)
+static int should_write_log(struct reftable_ref_store *refs, const char *refname)
 {
-	enum log_refs_config log_refs_cfg = log_all_ref_updates;
+	enum log_refs_config log_refs_cfg = refs->log_all_ref_updates;
 	if (log_refs_cfg == LOG_REFS_UNSET)
 		log_refs_cfg = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
 
 	switch (log_refs_cfg) {
 	case LOG_REFS_NONE:
-		return refs_reflog_exists(refs, refname);
+		return refs_reflog_exists(&refs->base, refname);
 	case LOG_REFS_ALWAYS:
 		return 1;
 	case LOG_REFS_NORMAL:
 		if (should_autocreate_reflog(log_refs_cfg, refname))
 			return 1;
-		return refs_reflog_exists(refs, refname);
+		return refs_reflog_exists(&refs->base, refname);
 	default:
 		BUG("unhandled core.logAllRefUpdates value %d", log_refs_cfg);
 	}
@@ -278,6 +279,7 @@ static struct ref_store *reftable_be_init(struct repository *repo,
 	base_ref_store_init(&refs->base, repo, gitdir, &refs_be_reftable);
 	strmap_init(&refs->worktree_stacks);
 	refs->store_flags = store_flags;
+	refs->log_all_ref_updates = repo_settings_get_log_all_ref_updates(repo);
 
 	refs->write_options.hash_id = repo->hash_algo->format_id;
 	refs->write_options.default_permissions = calc_shared_perm(0666 & ~mask);
@@ -1220,7 +1222,7 @@ static int write_transaction_table(struct reftable_writer *writer, void *cb_data
 		} else if (!(u->flags & REF_SKIP_CREATE_REFLOG) &&
 			   (u->flags & REF_HAVE_NEW) &&
 			   (u->flags & REF_FORCE_CREATE_REFLOG ||
-			    should_write_log(&arg->refs->base, u->refname))) {
+			    should_write_log(arg->refs, u->refname))) {
 			struct reftable_log_record *log;
 			int create_reflog = 1;
 

repo-settings.c

@@ -124,3 +124,19 @@ void prepare_repo_settings(struct repository *r)
 	 */
 	r->settings.command_requires_full_index = 1;
 }
+
+enum log_refs_config repo_settings_get_log_all_ref_updates(struct repository *repo)
+{
+	const char *value;
+
+	if (!repo_config_get_string_tmp(repo, "core.logallrefupdates", &value)) {
+		if (value && !strcasecmp(value, "always"))
+			return LOG_REFS_ALWAYS;
+		else if (git_config_bool("core.logallrefupdates", value))
+			return LOG_REFS_NORMAL;
+		else
+			return LOG_REFS_NONE;
+	}
+
+	return LOG_REFS_UNSET;
+}

repo-settings.h

@@ -65,4 +65,7 @@ struct repo_settings {
 
 void prepare_repo_settings(struct repository *r);
 
+/* Read the value for "core.logAllRefUpdates". */
+enum log_refs_config repo_settings_get_log_all_ref_updates(struct repository *repo);
+
 #endif /* REPO_SETTINGS_H */

setup.c

@@ -2354,7 +2354,7 @@ static int create_default_files(const char *template_path,
 	else {
 		git_config_set("core.bare", "false");
 		/* allow template config file to override the default */
-		if (log_all_ref_updates == LOG_REFS_UNSET)
+		if (repo_settings_get_log_all_ref_updates(the_repository) == LOG_REFS_UNSET)
 			git_config_set("core.logallrefupdates", "true");
 		if (needs_work_tree_config(original_git_dir, work_tree))
 			git_config_set("core.worktree", work_tree);