[thirdparty/git.git] / builtin-diff.c

/*
 * Builtin "git diff"
 *
 * Copyright (c) 2006 Junio C Hamano
 */
#include "cache.h"
#include "commit.h"
#include "blob.h"
#include "tag.h"
#include "diff.h"
#include "diffcore.h"
#include "revision.h"
#include "log-tree.h"
#include "builtin.h"

/* NEEDSWORK: struct object has place for name but we _do_
 * know mode when we extracted the blob out of a tree, which
 * we currently lose.
 */
struct blobinfo {
	unsigned char sha1[20];
	const char *name;
};

static const char builtin_diff_usage[] =
"diff <options> <rev>{0,2} -- <path>*";

static int builtin_diff_files(struct rev_info *revs,
			      int argc, const char **argv)
{
	int silent = 0;
	while (1 < argc) {
		const char *arg = argv[1];
		if (!strcmp(arg, "--base"))
			revs->max_count = 1;
		else if (!strcmp(arg, "--ours"))
			revs->max_count = 2;
		else if (!strcmp(arg, "--theirs"))
			revs->max_count = 3;
		else if (!strcmp(arg, "-q"))
			silent = 1;
		else
			usage(builtin_diff_usage);
		argv++; argc--;
	}
	/*
	 * Make sure there are NO revision (i.e. pending object) parameter,
	 * specified rev.max_count is reasonable (0 <= n <= 3), and
	 * there is no other revision filtering parameter.
	 */
	if (revs->pending.nr ||
	    revs->min_age != -1 ||
	    revs->max_age != -1 ||
	    3 < revs->max_count)
		usage(builtin_diff_usage);
	if (revs->max_count < 0 &&
	    (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
		revs->combine_merges = revs->dense_combined_merges = 1;
	/*
	 * Backward compatibility wart - "diff-files -s" used to
	 * defeat the common diff option "-s" which asked for
	 * DIFF_FORMAT_NO_OUTPUT.
	 */
	if (revs->diffopt.output_format == DIFF_FORMAT_NO_OUTPUT)
		revs->diffopt.output_format = DIFF_FORMAT_RAW;
	return run_diff_files(revs, silent);
}

static void stuff_change(struct diff_options *opt,
			 unsigned old_mode, unsigned new_mode,
			 const unsigned char *old_sha1,
			 const unsigned char *new_sha1,
			 const char *old_name,
			 const char *new_name)
{
	struct diff_filespec *one, *two;

	if (memcmp(null_sha1, old_sha1, 20) &&
	    memcmp(null_sha1, new_sha1, 20) &&
	    !memcmp(old_sha1, new_sha1, 20))
		return;

	if (opt->reverse_diff) {
		unsigned tmp;
		const unsigned char *tmp_u;
		const char *tmp_c;
		tmp = old_mode; old_mode = new_mode; new_mode = tmp;
		tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
		tmp_c = old_name; old_name = new_name; new_name = tmp_c;
	}
	one = alloc_filespec(old_name);
	two = alloc_filespec(new_name);
	fill_filespec(one, old_sha1, old_mode);
	fill_filespec(two, new_sha1, new_mode);

	/* NEEDSWORK: shouldn't this part of diffopt??? */
	diff_queue(&diff_queued_diff, one, two);
}

static int builtin_diff_b_f(struct rev_info *revs,
			    int argc, const char **argv,
			    struct blobinfo *blob,
			    const char *path)
{
	/* Blob vs file in the working tree*/
	struct stat st;

	if (argc > 1)
		usage(builtin_diff_usage);

	if (lstat(path, &st))
		die("'%s': %s", path, strerror(errno));
	if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
		die("'%s': not a regular file or symlink", path);
	stuff_change(&revs->diffopt,
		     canon_mode(st.st_mode), canon_mode(st.st_mode),
		     blob[0].sha1, null_sha1,
		     path, 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,
			      struct blobinfo *blob)
{
	/* Blobs: the arguments are reversed when setup_revisions()
	 * picked them up.
	 */
	unsigned mode = canon_mode(S_IFREG | 0644);

	if (argc > 1)
		usage(builtin_diff_usage);

	stuff_change(&revs->diffopt,
		     mode, mode,
		     blob[1].sha1, blob[0].sha1,
		     blob[0].name, blob[0].name);
	diffcore_std(&revs->diffopt);
	diff_flush(&revs->diffopt);
	return 0;
}

static int builtin_diff_index(struct rev_info *revs,
			      int argc, const char **argv)
{
	int cached = 0;
	while (1 < argc) {
		const char *arg = argv[1];
		if (!strcmp(arg, "--cached"))
			cached = 1;
		else
			usage(builtin_diff_usage);
		argv++; argc--;
	}
	/*
	 * Make sure there is one revision (i.e. pending object),
	 * and there is no revision filtering parameters.
	 */
	if (revs->pending.nr != 1 ||
	    revs->max_count != -1 || revs->min_age != -1 ||
	    revs->max_age != -1)
		usage(builtin_diff_usage);
	return run_diff_index(revs, cached);
}

static int builtin_diff_tree(struct rev_info *revs,
			     int argc, const char **argv,
			     struct object_array_entry *ent)
{
	const unsigned char *(sha1[2]);
	int swap = 0;

	if (argc > 1)
		usage(builtin_diff_usage);

	/* We saw two trees, ent[0] and ent[1].
	 * if ent[1] is uninteresting, they are swapped
	 */
	if (ent[1].item->flags & UNINTERESTING)
		swap = 1;
	sha1[swap] = ent[0].item->sha1;
	sha1[1-swap] = ent[1].item->sha1;
	diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
	log_tree_diff_flush(revs);
	return 0;
}

static int builtin_diff_combined(struct rev_info *revs,
				 int argc, const char **argv,
				 struct object_array_entry *ent,
				 int ents)
{
	const unsigned char (*parent)[20];
	int i;

	if (argc > 1)
		usage(builtin_diff_usage);

	if (!revs->dense_combined_merges && !revs->combine_merges)
		revs->dense_combined_merges = revs->combine_merges = 1;
	parent = xmalloc(ents * sizeof(*parent));
	/* Again, the revs are all reverse */
	for (i = 0; i < ents; i++)
		memcpy(parent + i, ent[ents - 1 - i].item->sha1, 20);
	diff_tree_combined(parent[0], parent + 1, ents - 1,
			   revs->dense_combined_merges, revs);
	return 0;
}

void add_head(struct rev_info *revs)
{
	unsigned char sha1[20];
	struct object *obj;
	if (get_sha1("HEAD", sha1))
		return;
	obj = parse_object(sha1);
	if (!obj)
		return;
	add_pending_object(revs, obj, "HEAD");
}

int cmd_diff(int argc, const char **argv, char **envp)
{
	int i;
	struct rev_info rev;
	struct object_array_entry ent[100];
	int ents = 0, blobs = 0, paths = 0;
	const char *path = NULL, *prefix;
	struct blobinfo blob[2];

	/*
	 * We could get N tree-ish in the rev.pending_objects list.
	 * Also there could be M blobs there, and P pathspecs.
	 *
	 * N=0, M=0:
	 *	cache vs files (diff-files)
	 * N=0, M=2:
	 *      compare two random blobs.  P must be zero.
	 * N=0, M=1, P=1:
	 *	compare a blob with a working tree file.
	 *
	 * N=1, M=0:
	 *      tree vs cache (diff-index --cached)
	 *
	 * N=2, M=0:
	 *      tree vs tree (diff-tree)
	 *
	 * Other cases are errors.
	 */

	prefix = setup_git_directory();
	git_config(git_diff_ui_config);
	init_revisions(&rev, prefix);

	argc = setup_revisions(argc, argv, &rev, NULL);
	if (!rev.diffopt.output_format) {
		rev.diffopt.output_format = DIFF_FORMAT_PATCH;
		diff_setup_done(&rev.diffopt);
	}

	/* Do we have --cached and not have a pending object, then
	 * default to HEAD by hand.  Eek.
	 */
	if (!rev.pending.nr) {
		int i;
		for (i = 1; i < argc; i++) {
			const char *arg = argv[i];
			if (!strcmp(arg, "--"))
				break;
			else if (!strcmp(arg, "--cached")) {
				add_head(&rev);
				break;
			}
		}
	}

	for (i = 0; i < rev.pending.nr; i++) {
		struct object_array_entry *list = rev.pending.objects+i;
		struct object *obj = list->item;
		const char *name = list->name;
		int flags = (obj->flags & UNINTERESTING);
		if (!obj->parsed)
			obj = parse_object(obj->sha1);
		obj = deref_tag(obj, NULL, 0);
		if (!obj)
			die("invalid object '%s' given.", name);
		if (obj->type == OBJ_COMMIT)
			obj = &((struct commit *)obj)->tree->object;
		if (obj->type == OBJ_TREE) {
			if (ARRAY_SIZE(ent) <= ents)
				die("more than %d trees given: '%s'",
				    (int) ARRAY_SIZE(ent), name);
			obj->flags |= flags;
			ent[ents].item = obj;
			ent[ents].name = name;
			ents++;
			continue;
		}
		if (obj->type == OBJ_BLOB) {
			if (2 <= blobs)
				die("more than two blobs given: '%s'", name);
			memcpy(blob[blobs].sha1, obj->sha1, 20);
			blob[blobs].name = name;
			blobs++;
			continue;

		}
		die("unhandled object '%s' given.", name);
	}
	if (rev.prune_data) {
		const char **pathspec = rev.prune_data;
		while (*pathspec) {
			if (!path)
				path = *pathspec;
			paths++;
			pathspec++;
		}
	}

	/*
	 * Now, do the arguments look reasonable?
	 */
	if (!ents) {
		switch (blobs) {
		case 0:
			return builtin_diff_files(&rev, argc, argv);
			break;
		case 1:
			if (paths != 1)
				usage(builtin_diff_usage);
			return builtin_diff_b_f(&rev, argc, argv, blob, path);
			break;
		case 2:
			if (paths)
				usage(builtin_diff_usage);
			return builtin_diff_blobs(&rev, argc, argv, blob);
			break;
		default:
			usage(builtin_diff_usage);
		}
	}
	else if (blobs)
		usage(builtin_diff_usage);
	else if (ents == 1)
		return builtin_diff_index(&rev, argc, argv);
	else if (ents == 2)
		return builtin_diff_tree(&rev, argc, argv, ent);
	else if ((ents == 3) && (ent[0].item->flags & UNINTERESTING)) {
		/* diff A...B where there is one sane merge base between
		 * A and B.  We have ent[0] == merge-base, ent[1] == A,
		 * and ent[2] == B.  Show diff between the base and B.
		 */
		return builtin_diff_tree(&rev, argc, argv, ent);
	}
	else
		return builtin_diff_combined(&rev, argc, argv,
					     ent, ents);
	usage(builtin_diff_usage);
}
Commit	Line	Data
65056021 JH	1	/*
	2	* Builtin "git diff"
	3	*
	4	* Copyright (c) 2006 Junio C Hamano
	5	*/
	6	#include "cache.h"
	7	#include "commit.h"
	8	#include "blob.h"
	9	#include "tag.h"
	10	#include "diff.h"
	11	#include "diffcore.h"
	12	#include "revision.h"
	13	#include "log-tree.h"
	14	#include "builtin.h"
	15
	16	/* NEEDSWORK: struct object has place for name but we _do_
	17	* know mode when we extracted the blob out of a tree, which
	18	* we currently lose.
	19	*/
	20	struct blobinfo {
	21	unsigned char sha1[20];
	22	const char *name;
	23	};
	24
	25	static const char builtin_diff_usage[] =
	26	"diff <options> <rev>{0,2} -- <path>*";
	27
	28	static int builtin_diff_files(struct rev_info *revs,
	29	int argc, const char **argv)
	30	{
	31	int silent = 0;
	32	while (1 < argc) {
	33	const char *arg = argv[1];
	34	if (!strcmp(arg, "--base"))
	35	revs->max_count = 1;
	36	else if (!strcmp(arg, "--ours"))
	37	revs->max_count = 2;
	38	else if (!strcmp(arg, "--theirs"))
	39	revs->max_count = 3;
	40	else if (!strcmp(arg, "-q"))
	41	silent = 1;
65056021 JH	42	else
	43	usage(builtin_diff_usage);
	44	argv++; argc--;
	45	}
	46	/*
	47	* Make sure there are NO revision (i.e. pending object) parameter,
0fe7c1de JH	48	* specified rev.max_count is reasonable (0 <= n <= 3), and
0fe7c1de JH	49	* there is no other revision filtering parameter.
65056021	50	*/
1f1e895f	51	if (revs->pending.nr \|\|
65056021	52	revs->min_age != -1 \|\|
0fe7c1de JH	53	revs->max_age != -1 \|\|
0fe7c1de JH	54	3 < revs->max_count)
65056021	55	usage(builtin_diff_usage);
0fe7c1de	56	if (revs->max_count < 0 &&
c6744349	57	(revs->diffopt.output_format & DIFF_FORMAT_PATCH))
0fe7c1de	58	revs->combine_merges = revs->dense_combined_merges = 1;
65056021 JH	59	/*
	60	* Backward compatibility wart - "diff-files -s" used to
	61	* defeat the common diff option "-s" which asked for
	62	* DIFF_FORMAT_NO_OUTPUT.
	63	*/
	64	if (revs->diffopt.output_format == DIFF_FORMAT_NO_OUTPUT)
	65	revs->diffopt.output_format = DIFF_FORMAT_RAW;
	66	return run_diff_files(revs, silent);
	67	}
	68
	69	static void stuff_change(struct diff_options *opt,
	70	unsigned old_mode, unsigned new_mode,
	71	const unsigned char *old_sha1,
	72	const unsigned char *new_sha1,
	73	const char *old_name,
	74	const char *new_name)
	75	{
	76	struct diff_filespec one, two;
	77
	78	if (memcmp(null_sha1, old_sha1, 20) &&
	79	memcmp(null_sha1, new_sha1, 20) &&
	80	!memcmp(old_sha1, new_sha1, 20))
	81	return;
	82
	83	if (opt->reverse_diff) {
	84	unsigned tmp;
d92f1dc6	85	const unsigned char *tmp_u;
65056021 JH	86	const char *tmp_c;
	87	tmp = old_mode; old_mode = new_mode; new_mode = tmp;
	88	tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
	89	tmp_c = old_name; old_name = new_name; new_name = tmp_c;
	90	}
	91	one = alloc_filespec(old_name);
	92	two = alloc_filespec(new_name);
	93	fill_filespec(one, old_sha1, old_mode);
	94	fill_filespec(two, new_sha1, new_mode);
	95
	96	/* NEEDSWORK: shouldn't this part of diffopt??? */
	97	diff_queue(&diff_queued_diff, one, two);
	98	}
	99
	100	static int builtin_diff_b_f(struct rev_info *revs,
	101	int argc, const char **argv,
	102	struct blobinfo *blob,
	103	const char *path)
	104	{
	105	/* Blob vs file in the working tree*/
	106	struct stat st;
	107
a610786f TH	108	if (argc > 1)
	109	usage(builtin_diff_usage);
	110
65056021 JH	111	if (lstat(path, &st))
	112	die("'%s': %s", path, strerror(errno));
	113	if (!(S_ISREG(st.st_mode) \|\| S_ISLNK(st.st_mode)))
	114	die("'%s': not a regular file or symlink", path);
	115	stuff_change(&revs->diffopt,
	116	canon_mode(st.st_mode), canon_mode(st.st_mode),
	117	blob[0].sha1, null_sha1,
065e0b12	118	path, path);
65056021 JH	119	diffcore_std(&revs->diffopt);
	120	diff_flush(&revs->diffopt);
	121	return 0;
	122	}
	123
	124	static int builtin_diff_blobs(struct rev_info *revs,
	125	int argc, const char **argv,
	126	struct blobinfo *blob)
	127	{
e4e23f3a JH	128	/* Blobs: the arguments are reversed when setup_revisions()
	129	* picked them up.
	130	*/
65056021 JH	131	unsigned mode = canon_mode(S_IFREG \| 0644);
65056021 JH	132
a610786f TH	133	if (argc > 1)
	134	usage(builtin_diff_usage);
	135
65056021 JH	136	stuff_change(&revs->diffopt,
65056021 JH	137	mode, mode,
e4e23f3a JH	138	blob[1].sha1, blob[0].sha1,
e4e23f3a JH	139	blob[0].name, blob[0].name);
65056021 JH	140	diffcore_std(&revs->diffopt);
	141	diff_flush(&revs->diffopt);
	142	return 0;
	143	}
	144
	145	static int builtin_diff_index(struct rev_info *revs,
	146	int argc, const char **argv)
	147	{
	148	int cached = 0;
	149	while (1 < argc) {
	150	const char *arg = argv[1];
	151	if (!strcmp(arg, "--cached"))
	152	cached = 1;
65056021 JH	153	else
	154	usage(builtin_diff_usage);
	155	argv++; argc--;
	156	}
	157	/*
	158	* Make sure there is one revision (i.e. pending object),
	159	* and there is no revision filtering parameters.
	160	*/
1f1e895f	161	if (revs->pending.nr != 1 \|\|
65056021 JH	162	revs->max_count != -1 \|\| revs->min_age != -1 \|\|
	163	revs->max_age != -1)
	164	usage(builtin_diff_usage);
	165	return run_diff_index(revs, cached);
	166	}
	167
	168	static int builtin_diff_tree(struct rev_info *revs,
	169	int argc, const char **argv,
1f1e895f	170	struct object_array_entry *ent)
65056021	171	{
65056021	172	const unsigned char *(sha1[2]);
1f1e895f	173	int swap = 0;
a610786f TH	174
	175	if (argc > 1)
	176	usage(builtin_diff_usage);
0fe7c1de JH	177
0fe7c1de JH	178	/* We saw two trees, ent[0] and ent[1].
82e5a82f	179	* if ent[1] is uninteresting, they are swapped
0fe7c1de	180	*/
1f1e895f LT	181	if (ent[1].item->flags & UNINTERESTING)
1f1e895f LT	182	swap = 1;
65056021 JH	183	sha1[swap] = ent[0].item->sha1;
	184	sha1[1-swap] = ent[1].item->sha1;
	185	diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
	186	log_tree_diff_flush(revs);
	187	return 0;
	188	}
	189
0fe7c1de JH	190	static int builtin_diff_combined(struct rev_info *revs,
0fe7c1de JH	191	int argc, const char **argv,
1f1e895f	192	struct object_array_entry *ent,
0fe7c1de JH	193	int ents)
	194	{
	195	const unsigned char (*parent)[20];
	196	int i;
	197
a610786f TH	198	if (argc > 1)
	199	usage(builtin_diff_usage);
	200
0fe7c1de JH	201	if (!revs->dense_combined_merges && !revs->combine_merges)
	202	revs->dense_combined_merges = revs->combine_merges = 1;
	203	parent = xmalloc(ents * sizeof(*parent));
	204	/* Again, the revs are all reverse */
	205	for (i = 0; i < ents; i++)
	206	memcpy(parent + i, ent[ents - 1 - i].item->sha1, 20);
	207	diff_tree_combined(parent[0], parent + 1, ents - 1,
	208	revs->dense_combined_merges, revs);
	209	return 0;
	210	}
	211
e686eb98	212	void add_head(struct rev_info *revs)
65056021 JH	213	{
	214	unsigned char sha1[20];
	215	struct object *obj;
	216	if (get_sha1("HEAD", sha1))
	217	return;
	218	obj = parse_object(sha1);
	219	if (!obj)
	220	return;
1f1e895f	221	add_pending_object(revs, obj, "HEAD");
65056021 JH	222	}
	223
	224	int cmd_diff(int argc, const char argv, char envp)
	225	{
1f1e895f	226	int i;
65056021	227	struct rev_info rev;
1f1e895f	228	struct object_array_entry ent[100];
65056021	229	int ents = 0, blobs = 0, paths = 0;
db6296a5	230	const char path = NULL, prefix;
65056021 JH	231	struct blobinfo blob[2];
	232
	233	/*
	234	* We could get N tree-ish in the rev.pending_objects list.
	235	* Also there could be M blobs there, and P pathspecs.
	236	*
	237	* N=0, M=0:
	238	* cache vs files (diff-files)
	239	* N=0, M=2:
	240	* compare two random blobs. P must be zero.
	241	* N=0, M=1, P=1:
	242	* compare a blob with a working tree file.
	243	*
	244	* N=1, M=0:
	245	* tree vs cache (diff-index --cached)
	246	*
	247	* N=2, M=0:
	248	* tree vs tree (diff-tree)
	249	*
	250	* Other cases are errors.
	251	*/
230f544e	252
db6296a5	253	prefix = setup_git_directory();
ef1d9c5a	254	git_config(git_diff_ui_config);
db6296a5	255	init_revisions(&rev, prefix);
65056021 JH	256
65056021 JH	257	argc = setup_revisions(argc, argv, &rev, NULL);
047fbe90	258	if (!rev.diffopt.output_format) {
c9b5ef99	259	rev.diffopt.output_format = DIFF_FORMAT_PATCH;
047fbe90 JH	260	diff_setup_done(&rev.diffopt);
047fbe90 JH	261	}
c9b5ef99	262
65056021 JH	263	/* Do we have --cached and not have a pending object, then
	264	* default to HEAD by hand. Eek.
	265	*/
1f1e895f	266	if (!rev.pending.nr) {
65056021 JH	267	int i;
	268	for (i = 1; i < argc; i++) {
	269	const char *arg = argv[i];
	270	if (!strcmp(arg, "--"))
	271	break;
	272	else if (!strcmp(arg, "--cached")) {
	273	add_head(&rev);
	274	break;
	275	}
	276	}
	277	}
	278
1f1e895f LT	279	for (i = 0; i < rev.pending.nr; i++) {
1f1e895f LT	280	struct object_array_entry *list = rev.pending.objects+i;
65056021 JH	281	struct object *obj = list->item;
	282	const char *name = list->name;
	283	int flags = (obj->flags & UNINTERESTING);
	284	if (!obj->parsed)
	285	obj = parse_object(obj->sha1);
	286	obj = deref_tag(obj, NULL, 0);
	287	if (!obj)
	288	die("invalid object '%s' given.", name);
1974632c	289	if (obj->type == OBJ_COMMIT)
65056021	290	obj = &((struct commit *)obj)->tree->object;
1974632c	291	if (obj->type == OBJ_TREE) {
0fe7c1de JH	292	if (ARRAY_SIZE(ent) <= ents)
0fe7c1de JH	293	die("more than %d trees given: '%s'",
334b506a	294	(int) ARRAY_SIZE(ent), name);
65056021 JH	295	obj->flags \|= flags;
	296	ent[ents].item = obj;
	297	ent[ents].name = name;
	298	ents++;
	299	continue;
	300	}
1974632c	301	if (obj->type == OBJ_BLOB) {
65056021 JH	302	if (2 <= blobs)
	303	die("more than two blobs given: '%s'", name);
	304	memcpy(blob[blobs].sha1, obj->sha1, 20);
	305	blob[blobs].name = name;
	306	blobs++;
	307	continue;
230f544e	308
65056021 JH	309	}
	310	die("unhandled object '%s' given.", name);
	311	}
	312	if (rev.prune_data) {
	313	const char **pathspec = rev.prune_data;
	314	while (*pathspec) {
	315	if (!path)
	316	path = *pathspec;
	317	paths++;
	318	pathspec++;
	319	}
	320	}
	321
	322	/*
	323	* Now, do the arguments look reasonable?
	324	*/
	325	if (!ents) {
	326	switch (blobs) {
	327	case 0:
	328	return builtin_diff_files(&rev, argc, argv);
	329	break;
	330	case 1:
	331	if (paths != 1)
	332	usage(builtin_diff_usage);
	333	return builtin_diff_b_f(&rev, argc, argv, blob, path);
	334	break;
	335	case 2:
0fe7c1de JH	336	if (paths)
0fe7c1de JH	337	usage(builtin_diff_usage);
65056021 JH	338	return builtin_diff_blobs(&rev, argc, argv, blob);
	339	break;
	340	default:
	341	usage(builtin_diff_usage);
	342	}
	343	}
	344	else if (blobs)
	345	usage(builtin_diff_usage);
	346	else if (ents == 1)
	347	return builtin_diff_index(&rev, argc, argv);
	348	else if (ents == 2)
	349	return builtin_diff_tree(&rev, argc, argv, ent);
9919f41c JH	350	else if ((ents == 3) && (ent[0].item->flags & UNINTERESTING)) {
	351	/* diff A...B where there is one sane merge base between
	352	* A and B. We have ent[0] == merge-base, ent[1] == A,
	353	* and ent[2] == B. Show diff between the base and B.
	354	*/
	355	return builtin_diff_tree(&rev, argc, argv, ent);
	356	}
0fe7c1de	357	else
9919f41c JH	358	return builtin_diff_combined(&rev, argc, argv,
9919f41c JH	359	ent, ents);
65056021 JH	360	usage(builtin_diff_usage);
65056021 JH	361	}