[pull] master from git:master

Documentation/RelNotes/2.52.0.adoc

@@ -182,6 +182,10 @@ including security updates, are included in this release.
    ignored") did not work well with "--name-only" and friends.
    (merge b55e6d36eb ly/diff-name-only-with-diff-from-content later to maint).
 
+ * The above caused regressions, which has been corrected.
+   (merge 623f7af2 jk/diff-from-contents-fix later to maint).
+   (merge 3da4413d jc/diff-from-contents-fix later to maint).
+
  * Documentation for "git rebase" has been updated.
    (merge 3f7f2b0359 je/doc-rebase later to maint).
 

diff.c

@@ -6828,18 +6828,38 @@ void diff_flush(struct diff_options *options)
 			     DIFF_FORMAT_NAME |
 			     DIFF_FORMAT_NAME_STATUS |
 			     DIFF_FORMAT_CHECKDIFF)) {
+		/*
+		 * make sure diff_Flush_patch_quietly() to be silent.
+		 */
+		FILE *dev_null = NULL;
+		int saved_color_moved = options->color_moved;
+
+		if (options->flags.diff_from_contents) {
+			dev_null = xfopen("/dev/null", "w");
+			options->color_moved = 0;
+		}
 		for (i = 0; i < q->nr; i++) {
 			struct diff_filepair *p = q->queue[i];
 
 			if (!check_pair_status(p))
 				continue;
 
-			if (options->flags.diff_from_contents &&
-			    !diff_flush_patch_quietly(p, options))
-				continue;
+			if (options->flags.diff_from_contents) {
+				FILE *saved_file = options->file;
+				int found_changes;
 
+				options->file = dev_null;
+				found_changes = diff_flush_patch_quietly(p, options);
+				options->file = saved_file;
+				if (!found_changes)
+					continue;
+			}
 			flush_one_pair(p, options);
 		}
+		if (options->flags.diff_from_contents) {
+			fclose(dev_null);
+			options->color_moved = saved_color_moved;
+		}
 		separator++;
 	}
 
@@ -6890,6 +6910,15 @@ void diff_flush(struct diff_options *options)
 	if (output_format & DIFF_FORMAT_NO_OUTPUT &&
 	    options->flags.exit_with_status &&
 	    options->flags.diff_from_contents) {
+		/*
+		 * run diff_flush_patch for the exit status. setting
+		 * options->file to /dev/null should be safe, because we
+		 * aren't supposed to produce any output anyway.
+		 */
+		diff_free_file(options);
+		options->file = xfopen("/dev/null", "w");
+		options->close_file = 1;
+		options->color_moved = 0;
 		for (i = 0; i < q->nr; i++) {
 			struct diff_filepair *p = q->queue[i];
 			if (check_pair_status(p))

t/t4035-diff-quiet.sh

@@ -50,6 +50,10 @@ test_expect_success 'git diff-tree HEAD HEAD' '
 	test_expect_code 0 git diff-tree --quiet HEAD HEAD >cnt &&
 	test_line_count = 0 cnt
 '
+test_expect_success 'git diff-tree -w HEAD^ HEAD' '
+	test_expect_code 1 git diff-tree --quiet -w HEAD^ HEAD >cnt &&
+	test_line_count = 0 cnt
+'
 test_expect_success 'git diff-files' '
 	test_expect_code 0 git diff-files --quiet >cnt &&
 	test_line_count = 0 cnt