Merge branch 'jk/diff-result-code-cleanup' into maint-2.42

"git diff --no-such-option" and other corner cases around the exit
status of the "diff" command has been corrected.

* jk/diff-result-code-cleanup:
  diff: drop useless "status" parameter from diff_result_code()
  diff: drop useless return values in git-diff helpers
  diff: drop useless return from run_diff_{files,index} functions
  diff: die when failing to read index in git-diff builtin
  diff: show usage for unknown builtin_diff_files() options
  diff-files: avoid negative exit value
  diff: spell DIFF_INDEX_CACHED out when calling run_diff_index()

1 files changed, 37 insertions, 42 deletions

diff --git a/builtin/diff.c b/builtin/diff.c
index b19530c996..0b313549c7 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -77,9 +77,9 @@ static void stuff_change(struct diff_options *opt,
 	diff_queue(&diff_queued_diff, one, two);
 }
 
-static int builtin_diff_b_f(struct rev_info *revs,
-			    int argc, const char **argv UNUSED,
-			    struct object_array_entry **blob)
+static void builtin_diff_b_f(struct rev_info *revs,
+			     int argc, const char **argv UNUSED,
+			     struct object_array_entry **blob)
 {
 	/* Blob vs file in the working tree*/
 	struct stat st;
@@ -109,12 +109,11 @@ static int builtin_diff_b_f(struct rev_info *revs,
 		     path);
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
-	return 0;
 }
 
-static int builtin_diff_blobs(struct rev_info *revs,
-			      int argc, const char **argv UNUSED,
-			      struct object_array_entry **blob)
+static void builtin_diff_blobs(struct rev_info *revs,
+			       int argc, const char **argv UNUSED,
+			       struct object_array_entry **blob)
 {
 	const unsigned mode = canon_mode(S_IFREG | 0644);
 
@@ -134,11 +133,10 @@ static int builtin_diff_blobs(struct rev_info *revs,
 		     blob_path(blob[0]), blob_path(blob[1]));
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
-	return 0;
 }
 
-static int builtin_diff_index(struct rev_info *revs,
-			      int argc, const char **argv)
+static void builtin_diff_index(struct rev_info *revs,
+			       int argc, const char **argv)
 {
 	unsigned int option = 0;
 	while (1 < argc) {
@@ -163,20 +161,18 @@ static int builtin_diff_index(struct rev_info *revs,
 		setup_work_tree();
 		if (repo_read_index_preload(the_repository,
 					    &revs->diffopt.pathspec, 0) < 0) {
-			perror("repo_read_index_preload");
-			return -1;
+			die_errno("repo_read_index_preload");
 		}
 	} else if (repo_read_index(the_repository) < 0) {
-		perror("repo_read_cache");
-		return -1;
+		die_errno("repo_read_cache");
 	}
-	return run_diff_index(revs, option);
+	run_diff_index(revs, option);
 }
 
-static int builtin_diff_tree(struct rev_info *revs,
-			     int argc, const char **argv,
-			     struct object_array_entry *ent0,
-			     struct object_array_entry *ent1)
+static void builtin_diff_tree(struct rev_info *revs,
+			      int argc, const char **argv,
+			      struct object_array_entry *ent0,
+			      struct object_array_entry *ent1)
 {
 	const struct object_id *(oid[2]);
 	struct object_id mb_oid;
@@ -209,13 +205,12 @@ static int builtin_diff_tree(struct rev_info *revs,
 	}
 	diff_tree_oid(oid[0], oid[1], "", &revs->diffopt);
 	log_tree_diff_flush(revs);
-	return 0;
 }
 
-static int builtin_diff_combined(struct rev_info *revs,
-				 int argc, const char **argv UNUSED,
-				 struct object_array_entry *ent,
-				 int ents, int first_non_parent)
+static void builtin_diff_combined(struct rev_info *revs,
+				  int argc, const char **argv UNUSED,
+				  struct object_array_entry *ent,
+				  int ents, int first_non_parent)
 {
 	struct oid_array parents = OID_ARRAY_INIT;
 	int i;
@@ -236,7 +231,6 @@ static int builtin_diff_combined(struct rev_info *revs,
 	}
 	diff_tree_combined(&ent[first_non_parent].item->oid, &parents, revs);
 	oid_array_clear(&parents);
-	return 0;
 }
 
 static void refresh_index_quietly(void)
@@ -254,7 +248,7 @@ static void refresh_index_quietly(void)
 	repo_update_index_if_able(the_repository, &lock_file);
 }
 
-static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
+static void builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
 {
 	unsigned int options = 0;
 
@@ -269,8 +263,10 @@ static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv
 			options |= DIFF_SILENT_ON_REMOVED;
 		else if (!strcmp(argv[1], "-h"))
 			usage(builtin_diff_usage);
-		else
-			return error(_("invalid option: %s"), argv[1]);
+		else {
+			error(_("invalid option: %s"), argv[1]);
+			usage(builtin_diff_usage);
+		}
 		argv++; argc--;
 	}
 
@@ -287,10 +283,9 @@ static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv
 	setup_work_tree();
 	if (repo_read_index_preload(the_repository, &revs->diffopt.pathspec,
 				    0) < 0) {
-		perror("repo_read_index_preload");
-		return -1;
+		die_errno("repo_read_index_preload");
 	}
-	return run_diff_files(revs, options);
+	run_diff_files(revs, options);
 }
 
 struct symdiff {
@@ -404,7 +399,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	int blobs = 0, paths = 0;
 	struct object_array_entry *blob[2];
 	int nongit = 0, no_index = 0;
-	int result = 0;
+	int result;
 	struct symdiff sdiff;
 
 	/*
@@ -583,17 +578,17 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	if (!ent.nr) {
 		switch (blobs) {
 		case 0:
-			result = builtin_diff_files(&rev, argc, argv);
+			builtin_diff_files(&rev, argc, argv);
 			break;
 		case 1:
 			if (paths != 1)
 				usage(builtin_diff_usage);
-			result = builtin_diff_b_f(&rev, argc, argv, blob);
+			builtin_diff_b_f(&rev, argc, argv, blob);
 			break;
 		case 2:
 			if (paths)
 				usage(builtin_diff_usage);
-			result = builtin_diff_blobs(&rev, argc, argv, blob);
+			builtin_diff_blobs(&rev, argc, argv, blob);
 			break;
 		default:
 			usage(builtin_diff_usage);
@@ -602,18 +597,18 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	else if (blobs)
 		usage(builtin_diff_usage);
 	else if (ent.nr == 1)
-		result = builtin_diff_index(&rev, argc, argv);
+		builtin_diff_index(&rev, argc, argv);
 	else if (ent.nr == 2) {
 		if (sdiff.warn)
 			warning(_("%s...%s: multiple merge bases, using %s"),
 				sdiff.left, sdiff.right, sdiff.base);
-		result = builtin_diff_tree(&rev, argc, argv,
-					   &ent.objects[0], &ent.objects[1]);
+		builtin_diff_tree(&rev, argc, argv,
+				  &ent.objects[0], &ent.objects[1]);
 	} else
-		result = builtin_diff_combined(&rev, argc, argv,
-					       ent.objects, ent.nr,
-					       first_non_parent);
-	result = diff_result_code(&rev.diffopt, result);
+		builtin_diff_combined(&rev, argc, argv,
+				      ent.objects, ent.nr,
+				      first_non_parent);
+	result = diff_result_code(&rev.diffopt);
 	if (1 < rev.diffopt.skip_stat_unmatch)
 		refresh_index_quietly();
 	release_revisions(&rev);