environment: move "branch.autoSetupMerge" into `struct repo_config_values`

The config value `branch.autoSetupMerge` is parsed in
`git_default_branch_config()` and stored in the global variable
`git_branch_track`. This global variable can be overwritten
by another repository when multiple Git repos run in the the same process.

Move this value into `struct repo_config_values` in the_repository to
retain current behaviours and move towards libifying Git.
Since the variable is no longer a global variable, it has been renamed to
`branch_track` in the struct `repo_config_values`.

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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 8 insertions, 4 deletions

diff --git a/builtin/branch.c b/builtin/branch.c
index c577b5d20f..a1a43380d0 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -724,6 +724,7 @@ int cmd_branch(int argc,
 	static struct ref_sorting *sorting;
 	struct string_list sorting_options = STRING_LIST_INIT_DUP;
 	struct ref_format format = REF_FORMAT_INIT;
+	struct repo_config_values *cfg = repo_config_values(the_repository);
 	int ret;
 
 	struct option options[] = {
@@ -795,7 +796,7 @@ int cmd_branch(int argc,
 	if (!sorting_options.nr)
 		string_list_append(&sorting_options, "refname");
 
-	track = git_branch_track;
+	track = cfg->branch_track;
 
 	head = refs_resolve_refdup(get_main_ref_store(the_repository), "HEAD",
 				   0, &head_oid, NULL);
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 66b69df6e6..736e20f808 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1588,6 +1588,7 @@ static void die_if_switching_to_a_branch_in_use(struct checkout_opts *opts,
 static int checkout_branch(struct checkout_opts *opts,
 			   struct branch_info *new_branch_info)
 {
+	struct repo_config_values *cfg = repo_config_values(the_repository);
 	int noop_switch = (!new_branch_info->name &&
 			   !opts->new_branch &&
 			   !opts->force_detach);
@@ -1631,7 +1632,7 @@ static int checkout_branch(struct checkout_opts *opts,
 		if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 			die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
 	} else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
-		opts->track = git_branch_track;
+		opts->track = cfg->branch_track;
 
 	if (new_branch_info->name && !new_branch_info->commit)
 		die(_("Cannot switch branch to a non-commit '%s'"),
diff --git a/builtin/push.c b/builtin/push.c
index 5b6cebbb85..7100ffba5d 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -151,6 +151,7 @@ static NORETURN void die_push_simple(struct branch *branch,
 	const char *advice_pushdefault_maybe = "";
 	const char *advice_automergesimple_maybe = "";
 	const char *short_upstream = branch->merge[0]->src;
+	struct repo_config_values *cfg = repo_config_values(the_repository);
 
 	skip_prefix(short_upstream, "refs/heads/", &short_upstream);
 
@@ -162,7 +163,7 @@ static NORETURN void die_push_simple(struct branch *branch,
 		advice_pushdefault_maybe = _("\n"
 				 "To choose either option permanently, "
 				 "see push.default in 'git help config'.\n");
-	if (git_branch_track != BRANCH_TRACK_SIMPLE)
+	if (cfg->branch_track != BRANCH_TRACK_SIMPLE)
 		advice_automergesimple_maybe = _("\n"
 				 "To avoid automatically configuring "
 				 "an upstream branch when its name\n"
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index d537ab087a..594cd107b3 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -3126,9 +3126,10 @@ static int module_create_branch(int argc, const char **argv, const char *prefix,
 		N_("git submodule--helper create-branch [-f|--force] [--create-reflog] [-q|--quiet] [-t|--track] [-n|--dry-run] <name> <start-oid> <start-name>"),
 		NULL
 	};
+	struct repo_config_values *cfg = repo_config_values(the_repository);
 
 	repo_config(the_repository, git_default_config, NULL);
-	track = git_branch_track;
+	track = cfg->branch_track;
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
 	if (argc != 3)