Use config snapshotting

This way we can assume we have a consistent view of the config situation
when we're looking up remote, branch, pack-objects, etc.

src/branch.c

@@ -306,17 +306,13 @@ int git_branch_name(
 
 static int retrieve_upstream_configuration(
 	const char **out,
-	git_repository *repo,
+	const git_config *config,
 	const char *canonical_branch_name,
 	const char *format)
 {
-	git_config *config;
 	git_buf buf = GIT_BUF_INIT;
 	int error;
 
-	if (git_repository_config__weakptr(&config, repo) < 0)
-		return -1;
-
 	if (git_buf_printf(&buf, format,
 		canonical_branch_name + strlen(GIT_REFS_HEADS_DIR)) < 0)
 			return -1;
@@ -336,6 +332,7 @@ int git_branch_upstream_name(
 	int error = -1;
 	git_remote *remote = NULL;
 	const git_refspec *refspec;
+	git_config *config, *repo_config;
 
 	assert(out && refname);
 
@@ -344,12 +341,18 @@ int git_branch_upstream_name(
 	if (!git_reference__is_branch(refname))
 		return not_a_local_branch(refname);
 
+	if ((error = git_repository_config__weakptr(&repo_config, repo)) < 0)
+		return error;
+
+	if ((error = git_config_snapshot(&config, repo_config)) < 0)
+		return error;
+
 	if ((error = retrieve_upstream_configuration(
-		&remote_name, repo, refname, "branch.%s.remote")) < 0)
+		&remote_name, config, refname, "branch.%s.remote")) < 0)
 			goto cleanup;
 
 	if ((error = retrieve_upstream_configuration(
-		&merge_name, repo, refname, "branch.%s.merge")) < 0)
+		&merge_name, config, refname, "branch.%s.merge")) < 0)
 			goto cleanup;
 
 	if (!*remote_name || !*merge_name) {
@@ -378,6 +381,7 @@ int git_branch_upstream_name(
 	error = git_buf_set(out, git_buf_cstr(&buf), git_buf_len(&buf));
 
 cleanup:
+	git_config_free(config);
 	git_remote_free(remote);
 	git_buf_free(&buf);
 	return error;

src/diff_driver.c

@@ -219,7 +219,7 @@ static int git_diff_driver_load(
 	git_diff_driver *drv = NULL;
 	size_t namelen = strlen(driver_name);
 	khiter_t pos;
-	git_config *cfg;
+	git_config *cfg, *repo_cfg;
 	git_buf name = GIT_BUF_INIT;
 	const git_config_entry *ce;
 	bool found_driver = false;
@@ -234,11 +234,14 @@ static int git_diff_driver_load(
 	}
 
 	/* if you can't read config for repo, just use default driver */
-	if (git_repository_config__weakptr(&cfg, repo) < 0) {
+	if (git_repository_config__weakptr(&repo_cfg, repo) < 0) {
 		giterr_clear();
 		goto done;
 	}
 
+	if ((error = git_config_snapshot(&cfg, repo_cfg)) < 0)
+		return error;
+
 	drv = git__calloc(1, sizeof(git_diff_driver) + namelen + 1);
 	GITERR_CHECK_ALLOC(drv);
 	drv->type = DIFF_DRIVER_AUTO;
@@ -321,6 +324,7 @@ static int git_diff_driver_load(
 
 done:
 	git_buf_free(&name);
+	git_config_free(cfg);
 
 	if (!*out) {
 		int error2 = git_diff_driver_builtin(out, reg, driver_name);

src/pack-objects.c

@@ -86,12 +86,15 @@ static unsigned name_hash(const char *name)
 
 static int packbuilder_config(git_packbuilder *pb)
 {
-	git_config *config;
+	git_config *config, *repo_config;
 	int ret;
 	int64_t val;
 
-	if (git_repository_config__weakptr(&config, pb->repo) < 0)
-		return -1;
+	if ((ret = git_repository_config__weakptr(&repo_config, pb->repo)) < 0)
+		return ret;
+
+	if ((ret = git_config_snapshot(&config, repo_config)) < 0)
+		return ret;
 
 #define config_get(KEY,DST,DFLT) do { \
 	ret = git_config_get_int64(&val, config, KEY); \
@@ -109,6 +112,8 @@ static int packbuilder_config(git_packbuilder *pb)
 
 #undef config_get
 
+	git_config_free(config);
+
 	return 0;
 }
 

src/remote.c

@@ -347,7 +347,7 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	git_buf buf = GIT_BUF_INIT;
 	const char *val;
 	int error = 0;
-	git_config *config;
+	git_config *config, *repo_config;
 	struct refspec_cb_data data = { NULL };
 	bool optional_setting_found = false, found;
 
@@ -356,9 +356,12 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	if ((error = ensure_remote_name_is_valid(name)) < 0)
 		return error;
 
-	if (git_repository_config__weakptr(&config, repo) < 0)
+	if (git_repository_config__weakptr(&repo_config, repo) < 0)
 		return -1;
 
+	if ((error = git_config_snapshot(&config, repo_config)) < 0)
+		return error;
+
 	remote = git__malloc(sizeof(git_remote));
 	GITERR_CHECK_ALLOC(remote);
 
@@ -437,6 +440,7 @@ int git_remote_load(git_remote **out, git_repository *repo, const char *name)
 	*out = remote;
 
 cleanup:
+	git_config_free(config);
 	git_buf_free(&buf);
 
 	if (error < 0)

src/repository.c

@@ -165,13 +165,9 @@ int git_repository_new(git_repository **out)
 	return 0;
 }
 
-static int load_config_data(git_repository *repo)
+static int load_config_data(git_repository *repo, const git_config *config)
 {
 	int is_bare;
-	git_config *config;
-
-	if (git_repository_config__weakptr(&config, repo) < 0)
-		return -1;
 
 	/* Try to figure out if it's bare, default to non-bare if it's not set */
 	if (git_config_get_bool(&is_bare, config, "core.bare") < 0)
@@ -182,19 +178,15 @@ static int load_config_data(git_repository *repo)
 	return 0;
 }
 
-static int load_workdir(git_repository *repo, git_buf *parent_path)
+static int load_workdir(git_repository *repo, git_config *config, git_buf *parent_path)
 {
 	int         error;
-	git_config *config;
 	const git_config_entry *ce;
 	git_buf     worktree = GIT_BUF_INIT;
 
 	if (repo->is_bare)
 		return 0;
 
-	if ((error = git_repository_config__weakptr(&config, repo)) < 0)
-		return error;
-
 	if ((error = git_config__lookup_entry(
 			&ce, config, "core.worktree", false)) < 0)
 		return error;
@@ -447,6 +439,7 @@ int git_repository_open_ext(
 	int error;
 	git_buf path = GIT_BUF_INIT, parent = GIT_BUF_INIT;
 	git_repository *repo;
+	git_config *repo_config, *config;
 
 	if (repo_ptr)
 		*repo_ptr = NULL;
@@ -461,15 +454,23 @@ int git_repository_open_ext(
 	repo->path_repository = git_buf_detach(&path);
 	GITERR_CHECK_ALLOC(repo->path_repository);
 
+	if ((error = git_repository_config__weakptr(&repo_config, repo)) < 0)
+		return error;
+
+	if ((error = git_config_snapshot(&config, repo_config)) < 0)
+		return error;
+
 	if ((flags & GIT_REPOSITORY_OPEN_BARE) != 0)
 		repo->is_bare = 1;
-	else if ((error = load_config_data(repo)) < 0 ||
-		(error = load_workdir(repo, &parent)) < 0)
+	else if ((error = load_config_data(repo, config)) < 0 ||
+		 (error = load_workdir(repo, config, &parent)) < 0)
 	{
+		git_config_free(config);
 		git_repository_free(repo);
 		return error;
 	}
 
+	git_config_free(config);
 	git_buf_free(&parent);
 	*repo_ptr = repo;
 	return 0;

src/signature.c

@@ -141,10 +141,13 @@ int git_signature_now(git_signature **sig_out, const char *name, const char *ema
 int git_signature_default(git_signature **out, git_repository *repo)
 {
 	int error;
-	git_config *cfg;
+	git_config *cfg, *repo_cfg;
 	const char *user_name, *user_email;
 
-	if ((error = git_repository_config(&cfg, repo)) < 0)
+	if ((error = git_repository_config__weakptr(&repo_cfg, repo)) < 0)
+		return error;
+
+	if ((error = git_config_snapshot(&cfg, repo_cfg)) < 0)
 		return error;
 
 	if (!(error = git_config_get_string(&user_name, cfg, "user.name")) &&