1 files changed, 27 insertions, 5 deletions

diff --git a/builtin/diff-tree.c b/builtin/diff-tree.c
index 2380c21951..be6417d166 100644
--- a/builtin/diff-tree.c
+++ b/builtin/diff-tree.c
@@ -3,6 +3,7 @@
 #include "commit.h"
 #include "log-tree.h"
 #include "builtin.h"
+#include "submodule.h"
 
 static struct rev_info log_tree_opt;
 
@@ -92,20 +93,34 @@ static const char diff_tree_usage[] =
 "  --root        include the initial commit as diff against /dev/null\n"
 COMMON_DIFF_OPTIONS_HELP;
 
+static void diff_tree_tweak_rev(struct rev_info *rev, struct setup_revision_opt *opt)
+{
+	if (!rev->diffopt.output_format) {
+		if (rev->dense_combined_merges)
+			rev->diffopt.output_format = DIFF_FORMAT_PATCH;
+		else
+			rev->diffopt.output_format = DIFF_FORMAT_RAW;
+	}
+}
+
 int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 {
 	int nr_sha1;
 	char line[1000];
 	struct object *tree1, *tree2;
 	static struct rev_info *opt = &log_tree_opt;
+	struct setup_revision_opt s_r_opt;
 	int read_stdin = 0;
 
 	init_revisions(opt, prefix);
+	gitmodules_config();
 	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
 	opt->abbrev = 0;
 	opt->diff = 1;
 	opt->disable_stdin = 1;
-	argc = setup_revisions(argc, argv, opt, NULL);
+	memset(&s_r_opt, 0, sizeof(s_r_opt));
+	s_r_opt.tweak = diff_tree_tweak_rev;
+	argc = setup_revisions(argc, argv, opt, &s_r_opt);
 
 	while (--argc > 0) {
 		const char *arg = *++argv;
@@ -117,9 +132,6 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 		usage(diff_tree_usage);
 	}
 
-	if (!opt->diffopt.output_format)
-		opt->diffopt.output_format = DIFF_FORMAT_RAW;
-
 	/*
 	 * NOTE! We expect "a ^b" to be equal to "a..b", so we
 	 * reverse the order of the objects if the second one
@@ -151,6 +163,9 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 	}
 
 	if (read_stdin) {
+		int saved_nrl = 0;
+		int saved_dcctc = 0;
+
 		if (opt->diffopt.detect_rename)
 			opt->diffopt.setup |= (DIFF_SETUP_USE_SIZE_CACHE |
 					       DIFF_SETUP_USE_CACHE);
@@ -161,9 +176,16 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
 				fputs(line, stdout);
 				fflush(stdout);
 			}
-			else
+			else {
 				diff_tree_stdin(line);
+				if (saved_nrl < opt->diffopt.needed_rename_limit)
+					saved_nrl = opt->diffopt.needed_rename_limit;
+				if (opt->diffopt.degraded_cc_to_c)
+					saved_dcctc = 1;
+			}
 		}
+		opt->diffopt.degraded_cc_to_c = saved_dcctc;
+		opt->diffopt.needed_rename_limit = saved_nrl;
 	}
 
 	return diff_result_code(&opt->diffopt, 0);