repository: move fetch_if_missing into struct repository

The global variable 'fetch_if_missing' controls whether a missing
object check should prompt a lazy fetch from a promisor remote.
In order to continue the libification effort, move it into
'struct repository' and initialize it to 1 by default to keep the
previous behavior.

builtin/fetch-pack.c, builtin/fsck.c, and builtin/rev-list.c are
entered via commands marked RUN_SETUP in git.c:commands[]. Their
'repo' parameter is only NULL when '-h' is given outside of a
repository, in which case either show_usage_if_asked() or
parse_options()'s own '-h' handling exits the process before
returning. We can therefore drop their UNUSED markers and assign
to 'repo' directly.

builtin/index-pack.c is entered via RUN_SETUP_GENTLY, so its
'repo' pointer can be NULL any time it is run outside of a
repository, not only with '-h'. We keep a NULL check there and fall
back to 'the_repository'.

builtin/pack-objects.c needs two adjustments to make 'repo' reach
every 'fetch_if_missing' call site: 'read_stdin_packs()' now takes a
'struct repository *'; 'option_parse_missing_action()', which
is registered as an OPT_CALLBACK, receives a 'repo' through the
option's 'value' field now.

Additionally, update the partial clone documentation to reflect
that this is now a per-repository flag.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Ayush Chandekar <ayu.chandekar@gmail.com>
Mentored-by: Olamide Caleb Bello <belkid98@gmail.com>
Signed-off-by: Tian Yuchen <cat@malon.dev>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/technical/partial-clone.adoc

@@ -159,7 +159,7 @@ and prefetch those objects in bulk.
 - `repack` in GC has been updated to not touch promisor packfiles at all,
   and to only repack other objects.
 
-- The global variable "fetch_if_missing" is used to control whether an
+- The per-repository flag "fetch_if_missing" is used to control whether an
   object lookup will attempt to dynamically fetch a missing object or
   report an error.
 +

builtin/fetch-pack.c

@@ -49,7 +49,7 @@ static void add_sought_entry(struct ref ***sought, int *nr, int *alloc,
 int cmd_fetch_pack(int argc,
 		   const char **argv,
 		   const char *prefix UNUSED,
-		   struct repository *repo UNUSED)
+		   struct repository *repo)
 {
 	int i, ret;
 	struct ref *fetched_refs = NULL, *remote_refs = NULL;
@@ -67,8 +67,6 @@ int cmd_fetch_pack(int argc,
 	struct packet_reader reader;
 	enum protocol_version version;
 
-	fetch_if_missing = 0;
-
 	packet_trace_identity("fetch-pack");
 
 	memset(&args, 0, sizeof(args));
@@ -77,6 +75,8 @@ int cmd_fetch_pack(int argc,
 
 	show_usage_if_asked(argc, argv, fetch_pack_usage);
 
+	repo->fetch_if_missing = 0;
+
 	for (i = 1; i < argc && *argv[i] == '-'; i++) {
 		const char *arg = argv[i];
 

builtin/fsck.c

@@ -1017,15 +1017,15 @@ int cmd_fsck(int argc,
 		.ref = NULL
 	};
 
-	/* fsck knows how to handle missing promisor objects */
-	fetch_if_missing = 0;
-
 	errors_found = 0;
 	disable_replace_refs();
 	save_commit_buffer = 0;
 
 	argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 
+	/* fsck knows how to handle missing promisor objects */
+	repo->fetch_if_missing = 0;
+
 	fsck_options_init(&fsck_walk_options, repo, FSCK_OPTIONS_DEFAULT);
 	fsck_walk_options.walk = mark_object;
 

builtin/index-pack.c

@@ -1886,7 +1886,7 @@ static void repack_local_links(void)
 int cmd_index_pack(int argc,
 		   const char **argv,
 		   const char *prefix,
-		   struct repository *repo UNUSED)
+		   struct repository *repo)
 {
 	int i, fix_thin_pack = 0, verify = 0, stat_only = 0, rev_index;
 	const char *curr_index;
@@ -1903,15 +1903,15 @@ int cmd_index_pack(int argc,
 	int report_end_of_input = 0;
 	int hash_algo = 0;
 
+	show_usage_if_asked(argc, argv, index_pack_usage);
+
 	/*
 	 * index-pack never needs to fetch missing objects except when
 	 * REF_DELTA bases are missing (which are explicitly handled). It only
 	 * accesses the repo to do hash collision checks and to check which
 	 * REF_DELTA bases need to be fetched.
 	 */
-	fetch_if_missing = 0;
-
-	show_usage_if_asked(argc, argv, index_pack_usage);
+	(repo ? repo : the_repository)->fetch_if_missing = 0;
 
 	disable_replace_refs();
 

builtin/pack-objects.c

@@ -4087,9 +4087,10 @@ static void stdin_packs_read_input(struct rev_info *revs,
 
 static void add_unreachable_loose_objects(struct rev_info *revs);
 
-static void read_stdin_packs(enum stdin_packs_mode mode, int rev_list_unpacked)
+static void read_stdin_packs(struct repository *repo,
+			     enum stdin_packs_mode mode, int rev_list_unpacked)
 {
-	int prev_fetch_if_missing = fetch_if_missing;
+	int prev_fetch_if_missing = repo->fetch_if_missing;
 	struct rev_info revs;
 
 	/*
@@ -4097,9 +4098,9 @@ static void read_stdin_packs(enum stdin_packs_mode mode, int rev_list_unpacked)
 	 * walk is best-effort though we don't want to perform backfill fetches
 	 * for them.
 	 */
-	fetch_if_missing = 0;
+	repo->fetch_if_missing = 0;
 
-	repo_init_revisions(the_repository, &revs, NULL);
+	repo_init_revisions(repo, &revs, NULL);
 	/*
 	 * Use a revision walk to fill in the namehash of objects in the include
 	 * packs. To save time, we'll avoid traversing through objects that are
@@ -4145,7 +4146,7 @@ static void read_stdin_packs(enum stdin_packs_mode mode, int rev_list_unpacked)
 	trace2_data_intmax("pack-objects", the_repository, "stdin_packs_hints",
 			   stdin_packs_hints_nr);
 
-	fetch_if_missing = prev_fetch_if_missing;
+	repo->fetch_if_missing = prev_fetch_if_missing;
 }
 
 static void add_cruft_object_entry(const struct object_id *oid, enum object_type type,
@@ -4455,9 +4456,11 @@ static void show_object__ma_allow_promisor(struct object *obj, const char *name,
 	show_object(obj, name, data);
 }
 
-static int option_parse_missing_action(const struct option *opt UNUSED,
+static int option_parse_missing_action(const struct option *opt,
 				       const char *arg, int unset)
 {
+	struct repository *repo = opt->value;
+
 	assert(arg);
 	assert(!unset);
 
@@ -4469,14 +4472,14 @@ static int option_parse_missing_action(const struct option *opt UNUSED,
 
 	if (!strcmp(arg, "allow-any")) {
 		arg_missing_action = MA_ALLOW_ANY;
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		fn_show_object = show_object__ma_allow_any;
 		return 0;
 	}
 
 	if (!strcmp(arg, "allow-promisor")) {
 		arg_missing_action = MA_ALLOW_PROMISOR;
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		fn_show_object = show_object__ma_allow_promisor;
 		return 0;
 	}
@@ -5118,7 +5121,7 @@ static int parse_stdin_packs_mode(const struct option *opt, const char *arg,
 int cmd_pack_objects(int argc,
 		     const char **argv,
 		     const char *prefix,
-		     struct repository *repo UNUSED)
+		     struct repository *repo)
 {
 	int use_internal_rev_list = 0;
 	int all_progress_implied = 0;
@@ -5225,7 +5228,7 @@ int cmd_pack_objects(int argc,
 			      N_("write a bitmap index if possible"),
 			      WRITE_BITMAP_QUIET, PARSE_OPT_HIDDEN),
 		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
-		OPT_CALLBACK_F(0, "missing", NULL, N_("action"),
+		OPT_CALLBACK_F(0, "missing", repo, N_("action"),
 		  N_("handling for missing objects"), PARSE_OPT_NONEG,
 		  option_parse_missing_action),
 		OPT_BOOL(0, "exclude-promisor-objects", &exclude_promisor_objects,
@@ -5345,7 +5348,7 @@ int cmd_pack_objects(int argc,
 				  exclude_promisor_objects_best_effort,
 				  "--exclude-promisor-objects-best-effort");
 	if (exclude_promisor_objects) {
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 
 		/* --stdin-packs handles promisor objects separately. */
 		if (!stdin_packs) {
@@ -5354,8 +5357,9 @@ int cmd_pack_objects(int argc,
 		}
 	} else if (exclude_promisor_objects_best_effort) {
 		use_internal_rev_list = 1;
-		fetch_if_missing = 0;
-		option_parse_missing_action(NULL, "allow-any", 0);
+		arg_missing_action = MA_ALLOW_ANY;
+		repo->fetch_if_missing = 0;
+		fn_show_object = show_object__ma_allow_any;
 		/* revs configured below */
 	}
 	if (unpack_unreachable || keep_unreachable || pack_loose_unreachable)
@@ -5471,7 +5475,7 @@ int cmd_pack_objects(int argc,
 		progress_state = start_progress(the_repository,
 						_("Enumerating objects"), 0);
 	if (stdin_packs) {
-		read_stdin_packs(stdin_packs, rev_list_unpacked);
+		read_stdin_packs(repo, stdin_packs, rev_list_unpacked);
 	} else if (cruft) {
 		read_cruft_objects();
 	} else if (!use_internal_rev_list) {

builtin/prune.c

@@ -194,7 +194,7 @@ int cmd_prune(int argc,
 	if (show_progress == -1)
 		show_progress = isatty(2);
 	if (exclude_promisor_objects) {
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		revs.exclude_promisor_objects = 1;
 	}
 

builtin/rev-list.c

@@ -500,7 +500,8 @@ static void print_disk_usage(off_t size)
 	strbuf_release(&sb);
 }
 
-static inline int parse_missing_action_value(const char *value)
+static inline int parse_missing_action_value(struct repository *repo,
+					     const char *value)
 {
 	if (!strcmp(value, "error")) {
 		arg_missing_action = MA_ERROR;
@@ -509,25 +510,25 @@ static inline int parse_missing_action_value(const char *value)
 
 	if (!strcmp(value, "allow-any")) {
 		arg_missing_action = MA_ALLOW_ANY;
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		return 1;
 	}
 
 	if (!strcmp(value, "print")) {
 		arg_missing_action = MA_PRINT;
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		return 1;
 	}
 
 	if (!strcmp(value, "print-info")) {
 		arg_missing_action = MA_PRINT_INFO;
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		return 1;
 	}
 
 	if (!strcmp(value, "allow-promisor")) {
 		arg_missing_action = MA_ALLOW_PROMISOR;
-		fetch_if_missing = 0;
+		repo->fetch_if_missing = 0;
 		return 1;
 	}
 
@@ -692,7 +693,7 @@ static void prepare_maximal_independent(struct rev_info *revs)
 int cmd_rev_list(int argc,
 		 const char **argv,
 		 const char *prefix,
-		 struct repository *repo UNUSED)
+		 struct repository *repo)
 {
 	struct rev_info revs;
 	struct rev_list_info info;
@@ -745,10 +746,10 @@ int cmd_rev_list(int argc,
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 		if (!strcmp(arg, "--exclude-promisor-objects")) {
-			fetch_if_missing = 0;
+			repo->fetch_if_missing = 0;
 			revs.exclude_promisor_objects = 1;
 		} else if (skip_prefix(arg, "--missing=", &arg)) {
-			parse_missing_action_value(arg);
+			parse_missing_action_value(repo, arg);
 		} else if (!strcmp(arg, "-z")) {
 			line_term = '\0';
 			info_term = '\0';

common-init.c

@@ -47,7 +47,7 @@ static void setup_environment(void)
 	update_ref_namespace(NAMESPACE_REPLACE, git_replace_ref_base);
 
 	if (git_env_bool(NO_LAZY_FETCH_ENVIRONMENT, 0))
-		fetch_if_missing = 0;
+		the_repository->fetch_if_missing = 0;
 }
 
 void init_git(const char **argv)

git.c

@@ -202,7 +202,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "--no-lazy-fetch")) {
-			fetch_if_missing = 0;
+			the_repository->fetch_if_missing = 0;
 			setenv(NO_LAZY_FETCH_ENVIRONMENT, "1", 1);
 			if (envchanged)
 				*envchanged = 1;

midx-write.c

@@ -865,7 +865,7 @@ static void find_commits_for_midx_bitmap(struct commit_stack *commits,
 	 * complain later that we don't have reachability closure (and fail
 	 * appropriately).
 	 */
-	fetch_if_missing = 0;
+	ctx->repo->fetch_if_missing = 0;
 	revs.exclude_promisor_objects = 1;
 
 	if (prepare_revision_walk(&revs))

odb.c

@@ -528,8 +528,6 @@ void disable_obj_read_lock(void)
 	pthread_mutex_destroy(&obj_read_mutex);
 }
 
-int fetch_if_missing = 1;
-
 static int register_all_submodule_sources(struct object_database *odb)
 {
 	int ret = odb->submodule_source_paths.nr;
@@ -595,7 +593,7 @@ static int do_oid_object_info_extended(struct object_database *odb,
 			continue;
 
 		/* Check if it is a missing object */
-		if (fetch_if_missing && repo_has_promisor_remote(odb->repo) &&
+		if (odb->repo->fetch_if_missing && repo_has_promisor_remote(odb->repo) &&
 		    !already_retried &&
 		    !(flags & OBJECT_INFO_SKIP_FETCH_OBJECT)) {
 			promisor_remote_get_direct(odb->repo, real, 1);

odb.h

@@ -15,14 +15,6 @@ struct repository;
 struct strbuf;
 struct strvec;
 
-/*
- * Set this to 0 to prevent odb_read_object_info_extended() from fetching missing
- * blobs. This has a difference only if extensions.partialClone is set.
- *
- * Its default value is 1.
- */
-extern int fetch_if_missing;
-
 /*
  * Compute the exact path an alternate is at and returns it. In case of
  * error NULL is returned and the human readable error is added to `err`

repository.c

@@ -74,6 +74,7 @@ void initialize_repository(struct repository *repo)
 	index_state_init(repo->index, repo);
 	repo->check_deprecated_config = true;
 	repo->bare_cfg = -1;
+	repo->fetch_if_missing = 1;
 	repo_config_values_init(&repo->config_values_private_);
 
 	/*

repository.h

@@ -184,6 +184,12 @@ struct repository {
 	/* True if commit-graph has been disabled within this process. */
 	int commit_graph_disabled;
 
+	/*
+	 * Controls whether the repository should lazily fetch missing
+	 * objects from promisor remotes. Defaults to 1.
+	 */
+	int fetch_if_missing;
+
 	/*
 	 * Lazily-populated cache mapping hook event names to configured hooks.
 	 * NULL until first hook use.

revision.c

@@ -2732,7 +2732,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->ignore_missing = 1;
 	} else if (opt && opt->allow_exclude_promisor_objects &&
 		   !strcmp(arg, "--exclude-promisor-objects")) {
-		if (fetch_if_missing)
+		if (revs->repo->fetch_if_missing)
 			BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
 		revs->exclude_promisor_objects = 1;
 	} else {