hash: require hash algorithm in empty_tree_oid_hex()

The `empty_tree_oid_hex()` function use `the_repository` to derive the
hash function that shall be used. Require callers to pass in the hash
algorithm to get rid of this implicit dependency.

While at it, remove the unused `empty_blob_oid_hex()` function.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

add-interactive.c

@@ -557,7 +557,7 @@ static int get_modified_files(struct repository *r,
 		s.skip_unseen = filter && i;
 
 		opt.def = is_initial ?
-			empty_tree_oid_hex() : oid_to_hex(&head_oid);
+			empty_tree_oid_hex(the_repository->hash_algo) : oid_to_hex(&head_oid);
 
 		repo_init_revisions(r, &rev, NULL);
 		setup_revisions(0, NULL, &rev, &opt);

add-patch.c

@@ -420,7 +420,7 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			    /* could be on an unborn branch */
 			    !strcmp("HEAD", s->revision) &&
 			    repo_get_oid(the_repository, "HEAD", &oid) ?
-			    empty_tree_oid_hex() : s->revision);
+			    empty_tree_oid_hex(the_repository->hash_algo) : s->revision);
 	}
 	color_arg_index = args.nr;
 	/* Use `--no-color` explicitly, just in case `diff.color = always`. */

builtin/merge.c

@@ -330,7 +330,8 @@ static void read_empty(const struct object_id *oid)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
 
-	strvec_pushl(&cmd.args, "read-tree", "-m", "-u", empty_tree_oid_hex(),
+	strvec_pushl(&cmd.args, "read-tree", "-m", "-u",
+		     empty_tree_oid_hex(the_repository->hash_algo),
 		     oid_to_hex(oid), NULL);
 	cmd.git_cmd = 1;
 

builtin/receive-pack.c

@@ -1371,7 +1371,7 @@ static const char *push_to_deploy(unsigned char *sha1,
 	strvec_pushl(&child.args, "diff-index", "--quiet", "--cached",
 		     "--ignore-submodules",
 		     /* diff-index with either HEAD or an empty tree */
-		     head_has_history() ? "HEAD" : empty_tree_oid_hex(),
+		     head_has_history() ? "HEAD" : empty_tree_oid_hex(the_repository->hash_algo),
 		     "--", NULL);
 	strvec_pushv(&child.env, env->v);
 	child.no_stdin = 1;

hash-ll.h

@@ -347,8 +347,7 @@ static inline int is_null_oid(const struct object_id *oid)
 	return !memcmp(oid->hash, null_hash, GIT_MAX_RAWSZ);
 }
 
-const char *empty_tree_oid_hex(void);
-const char *empty_blob_oid_hex(void);
+const char *empty_tree_oid_hex(const struct git_hash_algo *algop);
 
 static inline int is_empty_blob_oid(const struct object_id *oid,
 				    const struct git_hash_algo *algop)

object-file.c

@@ -227,16 +227,10 @@ const struct object_id *null_oid(void)
 	return the_hash_algo->null_oid;
 }
 
-const char *empty_tree_oid_hex(void)
+const char *empty_tree_oid_hex(const struct git_hash_algo *algop)
 {
 	static char buf[GIT_MAX_HEXSZ + 1];
-	return oid_to_hex_r(buf, the_hash_algo->empty_tree);
-}
-
-const char *empty_blob_oid_hex(void)
-{
-	static char buf[GIT_MAX_HEXSZ + 1];
-	return oid_to_hex_r(buf, the_hash_algo->empty_blob);
+	return oid_to_hex_r(buf, algop->empty_tree);
 }
 
 int hash_algo_by_name(const char *name)

sequencer.c

@@ -2263,7 +2263,7 @@ static int do_pick_commit(struct repository *r,
 			unborn = 1;
 		} else if (unborn)
 			oidcpy(&head, the_hash_algo->empty_tree);
-		if (index_differs_from(r, unborn ? empty_tree_oid_hex() : "HEAD",
+		if (index_differs_from(r, unborn ? empty_tree_oid_hex(the_repository->hash_algo) : "HEAD",
 				       NULL, 0))
 			return error_dirty_index(r, opts);
 	}

submodule.c

@@ -2119,7 +2119,7 @@ static void submodule_reset_index(const char *path, const char *super_prefix)
 	strvec_pushf(&cp.args, "--super-prefix=%s%s/",
 		     (super_prefix ? super_prefix : ""), path);
 
-	strvec_push(&cp.args, empty_tree_oid_hex());
+	strvec_push(&cp.args, empty_tree_oid_hex(the_repository->hash_algo));
 
 	if (run_command(&cp))
 		die(_("could not reset submodule index"));
@@ -2229,9 +2229,9 @@ int submodule_move_head(const char *path, const char *super_prefix,
 		strvec_push(&cp.args, "-m");
 
 	if (!(flags & SUBMODULE_MOVE_HEAD_FORCE))
-		strvec_push(&cp.args, old_head ? old_head : empty_tree_oid_hex());
+		strvec_push(&cp.args, old_head ? old_head : empty_tree_oid_hex(the_repository->hash_algo));
 
-	strvec_push(&cp.args, new_head ? new_head : empty_tree_oid_hex());
+	strvec_push(&cp.args, new_head ? new_head : empty_tree_oid_hex(the_repository->hash_algo));
 
 	if (run_command(&cp)) {
 		ret = error(_("Submodule '%s' could not be updated."), path);

wt-status.c

@@ -641,7 +641,7 @@ static void wt_status_collect_changes_index(struct wt_status *s)
 
 	repo_init_revisions(s->repo, &rev, NULL);
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex(the_repository->hash_algo) : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.flags.override_submodule_config = 1;
@@ -1136,7 +1136,7 @@ static void wt_longstatus_print_verbose(struct wt_status *s)
 	rev.diffopt.ita_invisible_in_index = 1;
 
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex(the_repository->hash_algo) : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;