repository: create disable_replace_refs()

Several builtins depend on being able to disable the replace references
so we actually operate on each object individually. These currently do
so by directly mutating the 'read_replace_refs' global.

A future change will move this global into a different place, so it will
be necessary to change all of these lines. However, we can simplify that
transition by abstracting the purpose of these global assignments with a
method call.

We will need to keep this read_replace_refs global forever, as we want
to make sure that we never use replace refs throughout the life of the
process if this method is called. Future changes may present a
repository-scoped version of the variable to represent that repository's
core.useReplaceRefs config value, but a zero-valued read_replace_refs
will always override such a setting.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/cat-file.c

@@ -805,7 +805,7 @@ static int batch_objects(struct batch_options *opt)
 		if (repo_has_promisor_remote(the_repository))
 			warning("This repository uses promisor remotes. Some objects may not be loaded.");
 
-		read_replace_refs = 0;
+		disable_replace_refs();
 
 		cb.opt = opt;
 		cb.expand = &data;

builtin/commit-graph.c

@@ -324,7 +324,7 @@ int cmd_commit_graph(int argc, const char **argv, const char *prefix)
 
 	git_config(git_default_config, NULL);
 
-	read_replace_refs = 0;
+	disable_replace_refs();
 	save_commit_buffer = 0;
 
 	argc = parse_options(argc, argv, prefix, options,

builtin/fsck.c

@@ -927,7 +927,7 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 	fetch_if_missing = 0;
 
 	errors_found = 0;
-	read_replace_refs = 0;
+	disable_replace_refs();
 	save_commit_buffer = 0;
 
 	argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);

builtin/index-pack.c

@@ -1752,7 +1752,7 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage(index_pack_usage);
 
-	read_replace_refs = 0;
+	disable_replace_refs();
 	fsck_options.walk = mark_link;
 
 	reset_pack_idx_option(&opts);

builtin/pack-objects.c

@@ -4284,7 +4284,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	if (DFS_NUM_STATES > (1 << OE_DFS_STATE_BITS))
 		BUG("too many dfs states, increase OE_DFS_STATE_BITS");
 
-	read_replace_refs = 0;
+	disable_replace_refs();
 
 	sparse = git_env_bool("GIT_TEST_PACK_SPARSE", -1);
 	if (the_repository->gitdir) {

builtin/prune.c

@@ -164,7 +164,7 @@ int cmd_prune(int argc, const char **argv, const char *prefix)
 
 	expire = TIME_MAX;
 	save_commit_buffer = 0;
-	read_replace_refs = 0;
+	disable_replace_refs();
 	repo_init_revisions(the_repository, &revs, prefix);
 
 	argc = parse_options(argc, argv, prefix, options, prune_usage, 0);

builtin/replace.c

@@ -566,7 +566,7 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
-	read_replace_refs = 0;
+	disable_replace_refs();
 	git_config(git_default_config, NULL);
 
 	argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);

builtin/unpack-objects.c

@@ -609,7 +609,7 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix UNUSED)
 	int i;
 	struct object_id oid;
 
-	read_replace_refs = 0;
+	disable_replace_refs();
 
 	git_config(git_default_config, NULL);
 

builtin/upload-pack.c

@@ -36,7 +36,7 @@ int cmd_upload_pack(int argc, const char **argv, const char *prefix)
 	};
 
 	packet_trace_identity("upload-pack");
-	read_replace_refs = 0;
+	disable_replace_refs();
 
 	argc = parse_options(argc, argv, prefix, options, upload_pack_usage, 0);
 

environment.c

@@ -185,7 +185,7 @@ void setup_git_env(const char *git_dir)
 	strvec_clear(&to_free);
 
 	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
-		read_replace_refs = 0;
+		disable_replace_refs();
 	replace_ref_base = getenv(GIT_REPLACE_REF_BASE_ENVIRONMENT);
 	git_replace_ref_base = xstrdup(replace_ref_base ? replace_ref_base
 							  : "refs/replace/");

git.c

@@ -185,7 +185,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--no-replace-objects")) {
-			read_replace_refs = 0;
+			disable_replace_refs();
 			setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 			if (envchanged)
 				*envchanged = 1;

replace-object.c

@@ -84,3 +84,8 @@ const struct object_id *do_lookup_replace_object(struct repository *r,
 	}
 	die(_("replace depth too high for object %s"), oid_to_hex(oid));
 }
+
+void disable_replace_refs(void)
+{
+	read_replace_refs = 0;
+}

replace-object.h

@@ -48,4 +48,12 @@ static inline const struct object_id *lookup_replace_object(struct repository *r
 	return do_lookup_replace_object(r, oid);
 }
 
+/*
+ * Some commands override config and environment settings for using
+ * replace references. Use this method to disable the setting and ensure
+ * those other settings will not override this choice. This applies
+ * globally to all in-process repositories.
+ */
+void disable_replace_refs(void);
+
 #endif /* REPLACE_OBJECT_H */