1 files changed, 28 insertions, 13 deletions

diff --git a/builtin/diff-index.c b/builtin/diff-index.c
index 522f4fdffd..35dc9b23ee 100644
--- a/builtin/diff-index.c
+++ b/builtin/diff-index.c
@@ -1,20 +1,22 @@
 #include "cache.h"
 #include "config.h"
 #include "diff.h"
+#include "diff-merges.h"
 #include "commit.h"
 #include "revision.h"
 #include "builtin.h"
 #include "submodule.h"
 
 static const char diff_cache_usage[] =
-"git diff-index [-m] [--cached] "
+"git diff-index [-m] [--cached] [--merge-base] "
 "[<common-diff-options>] <tree-ish> [<path>...]"
+"\n"
 COMMON_DIFF_OPTIONS_HELP;
 
 int cmd_diff_index(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info rev;
-	int cached = 0;
+	unsigned int option = 0;
 	int i;
 	int result;
 
@@ -22,22 +24,34 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
 		usage(diff_cache_usage);
 
 	git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
-	init_revisions(&rev, prefix);
+	repo_init_revisions(the_repository, &rev, prefix);
 	rev.abbrev = 0;
-	precompose_argv(argc, argv);
+	prefix = precompose_argv_prefix(argc, argv, prefix);
+
+	/*
+	 * We need (some of) diff for merges options (e.g., --cc), and we need
+	 * to avoid conflict with our own meaning of "-m".
+	 */
+	diff_merges_suppress_m_parsing();
 
 	argc = setup_revisions(argc, argv, &rev, NULL);
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 
 		if (!strcmp(arg, "--cached"))
-			cached = 1;
+			option |= DIFF_INDEX_CACHED;
+		else if (!strcmp(arg, "--merge-base"))
+			option |= DIFF_INDEX_MERGE_BASE;
+		else if (!strcmp(arg, "-m"))
+			rev.match_missing = 1;
 		else
 			usage(diff_cache_usage);
 	}
 	if (!rev.diffopt.output_format)
 		rev.diffopt.output_format = DIFF_FORMAT_RAW;
 
+	rev.diffopt.rotate_to_strict = 1;
+
 	/*
 	 * Make sure there is one revision (i.e. pending object),
 	 * and there is no revision filtering parameters.
@@ -45,17 +59,18 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
 	if (rev.pending.nr != 1 ||
 	    rev.max_count != -1 || rev.min_age != -1 || rev.max_age != -1)
 		usage(diff_cache_usage);
-	if (!cached) {
+	if (!(option & DIFF_INDEX_CACHED)) {
 		setup_work_tree();
-		if (read_cache_preload(&rev.diffopt.pathspec) < 0) {
-			perror("read_cache_preload");
+		if (repo_read_index_preload(the_repository, &rev.diffopt.pathspec, 0) < 0) {
+			perror("repo_read_index_preload");
 			return -1;
 		}
-	} else if (read_cache() < 0) {
-		perror("read_cache");
+	} else if (repo_read_index(the_repository) < 0) {
+		perror("repo_read_index");
 		return -1;
 	}
-	result = run_diff_index(&rev, cached);
-	UNLEAK(rev);
-	return diff_result_code(&rev.diffopt, result);
+	result = run_diff_index(&rev, option);
+	result = diff_result_code(&rev.diffopt, result);
+	release_revisions(&rev);
+	return result;
 }