1 files changed, 129 insertions, 100 deletions

diff --git a/diff.c b/diff.c
index 46260ed7a1..cc8e81290a 100644
--- a/diff.c
+++ b/diff.c
@@ -13,7 +13,6 @@
 #include "run-command.h"
 #include "utf8.h"
 #include "userdiff.h"
-#include "sigchain.h"
 #include "submodule-config.h"
 #include "submodule.h"
 #include "ll-merge.h"
@@ -27,6 +26,7 @@
 #endif
 
 static int diff_detect_rename_default;
+static int diff_compaction_heuristic; /* experimental */
 static int diff_rename_limit_default = 400;
 static int diff_suppress_blank_empty;
 static int diff_use_color_default = -1;
@@ -169,6 +169,11 @@ long parse_algorithm_value(const char *value)
  * never be affected by the setting of diff.renames
  * the user happens to have in the configuration file.
  */
+void init_diff_ui_defaults(void)
+{
+	diff_detect_rename_default = 1;
+}
+
 int git_diff_ui_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
@@ -185,6 +190,10 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		diff_detect_rename_default = git_config_rename(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "diff.compactionheuristic")) {
+		diff_compaction_heuristic = git_config_bool(var, value);
+		return 0;
+	}
 	if (!strcmp(var, "diff.autorefreshindex")) {
 		diff_auto_refresh_index = git_config_bool(var, value);
 		return 0;
@@ -322,7 +331,7 @@ static struct diff_tempfile {
 	 */
 	const char *name;
 
-	char hex[41];
+	char hex[GIT_SHA1_HEXSZ + 1];
 	char mode[10];
 
 	/*
@@ -345,7 +354,6 @@ struct emit_callback {
 	const char **label_path;
 	struct diff_words_data *diff_words;
 	struct diff_options *opt;
-	int *found_changesp;
 	struct strbuf *header;
 };
 
@@ -713,7 +721,6 @@ static void emit_rewrite_diff(const char *name_a,
 
 	memset(&ecbdata, 0, sizeof(ecbdata));
 	ecbdata.color_diff = want_color(o->use_color);
-	ecbdata.found_changesp = &o->found_changes;
 	ecbdata.ws_rule = whitespace_rule(name_b);
 	ecbdata.opt = o;
 	if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
@@ -1207,12 +1214,13 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 	struct diff_options *o = ecbdata->opt;
 	const char *line_prefix = diff_line_prefix(o);
 
+	o->found_changes = 1;
+
 	if (ecbdata->header) {
-		fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
+		fprintf(o->file, "%s", ecbdata->header->buf);
 		strbuf_reset(ecbdata->header);
 		ecbdata->header = NULL;
 	}
-	*(ecbdata->found_changesp) = 1;
 
 	if (ecbdata->label_path[0]) {
 		const char *name_a_tab, *name_b_tab;
@@ -1220,9 +1228,9 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 		name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 		name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 
-		fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
+		fprintf(o->file, "%s%s--- %s%s%s\n",
 			line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
-		fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
+		fprintf(o->file, "%s%s+++ %s%s%s\n",
 			line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
 		ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 	}
@@ -1240,15 +1248,7 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 		find_lno(line, ecbdata);
 		emit_hunk_header(ecbdata, line, len);
 		if (line[len-1] != '\n')
-			putc('\n', ecbdata->opt->file);
-		return;
-	}
-
-	if (len < 1) {
-		emit_line(ecbdata->opt, reset, reset, line, len);
-		if (ecbdata->diff_words
-		    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
-			fputs("~\n", ecbdata->opt->file);
+			putc('\n', o->file);
 		return;
 	}
 
@@ -1273,8 +1273,8 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 		}
 		diff_words_flush(ecbdata);
 		if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
-			emit_line(ecbdata->opt, context, reset, line, len);
-			fputs("~\n", ecbdata->opt->file);
+			emit_line(o, context, reset, line, len);
+			fputs("~\n", o->file);
 		} else {
 			/*
 			 * Skip the prefix character, if any.  With
@@ -1285,7 +1285,7 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 			      line++;
 			      len--;
 			}
-			emit_line(ecbdata->opt, context, reset, line, len);
+			emit_line(o, context, reset, line, len);
 		}
 		return;
 	}
@@ -1307,8 +1307,7 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 	default:
 		/* incomplete line at the end */
 		ecbdata->lno_in_preimage++;
-		emit_line(ecbdata->opt,
-			  diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
+		emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
 			  reset, line, len);
 		break;
 	}
@@ -1924,8 +1923,8 @@ static void show_dirstat(struct diff_options *options)
 
 		name = p->two->path ? p->two->path : p->one->path;
 
-		if (p->one->sha1_valid && p->two->sha1_valid)
-			content_changed = hashcmp(p->one->sha1, p->two->sha1);
+		if (p->one->oid_valid && p->two->oid_valid)
+			content_changed = oidcmp(&p->one->oid, &p->two->oid);
 		else
 			content_changed = 1;
 
@@ -2297,7 +2296,8 @@ static void builtin_diff(const char *name_a,
 		const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
 		show_submodule_summary(o->file, one->path ? one->path : two->path,
 				line_prefix,
-				one->sha1, two->sha1, two->dirty_submodule,
+				one->oid.hash, two->oid.hash,
+				two->dirty_submodule,
 				meta, del, add, reset);
 		return;
 	}
@@ -2375,7 +2375,7 @@ static void builtin_diff(const char *name_a,
 		if (!one->data && !two->data &&
 		    S_ISREG(one->mode) && S_ISREG(two->mode) &&
 		    !DIFF_OPT_TST(o, BINARY)) {
-			if (!hashcmp(one->sha1, two->sha1)) {
+			if (!oidcmp(&one->oid, &two->oid)) {
 				if (must_show_header)
 					fprintf(o->file, "%s", header.buf);
 				goto free_ab_and_return;
@@ -2428,7 +2428,6 @@ static void builtin_diff(const char *name_a,
 		memset(&ecbdata, 0, sizeof(ecbdata));
 		ecbdata.label_path = lbl;
 		ecbdata.color_diff = want_color(o->use_color);
-		ecbdata.found_changesp = &o->found_changes;
 		ecbdata.ws_rule = whitespace_rule(name_b);
 		if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
 			check_blank_at_eof(&mf1, &mf2, &ecbdata);
@@ -2496,7 +2495,7 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		return;
 	}
 
-	same_contents = !hashcmp(one->sha1, two->sha1);
+	same_contents = !oidcmp(&one->oid, &two->oid);
 
 	if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
 		data->is_binary = 1;
@@ -2608,12 +2607,9 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
 
 struct diff_filespec *alloc_filespec(const char *path)
 {
-	int namelen = strlen(path);
-	struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
+	struct diff_filespec *spec;
 
-	memset(spec, 0, sizeof(*spec));
-	spec->path = (char *)(spec + 1);
-	memcpy(spec->path, path, namelen+1);
+	FLEXPTR_ALLOC_STR(spec, path, path);
 	spec->count = 1;
 	spec->is_binary = -1;
 	return spec;
@@ -2632,8 +2628,8 @@ void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 {
 	if (mode) {
 		spec->mode = canon_mode(mode);
-		hashcpy(spec->sha1, sha1);
-		spec->sha1_valid = sha1_valid;
+		hashcpy(spec->oid.hash, sha1);
+		spec->oid_valid = sha1_valid;
 	}
 }
 
@@ -2676,6 +2672,13 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
 	if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
 		return 0;
 
+	/*
+	 * Similarly, if we'd have to convert the file contents anyway, that
+	 * makes the optimization not worthwhile.
+	 */
+	if (!want_file && would_convert_to_git(name))
+		return 0;
+
 	len = strlen(name);
 	pos = cache_name_pos(name, len);
 	if (pos < 0)
@@ -2708,21 +2711,22 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
 
 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
 {
-	int len;
-	char *data = xmalloc(100), *dirty = "";
+	struct strbuf buf = STRBUF_INIT;
+	char *dirty = "";
 
 	/* Are we looking at the work tree? */
 	if (s->dirty_submodule)
 		dirty = "-dirty";
 
-	len = snprintf(data, 100,
-		       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
-	s->data = data;
-	s->size = len;
-	s->should_free = 1;
+	strbuf_addf(&buf, "Subproject commit %s%s\n",
+		    oid_to_hex(&s->oid), dirty);
+	s->size = buf.len;
 	if (size_only) {
 		s->data = NULL;
-		free(data);
+		strbuf_release(&buf);
+	} else {
+		s->data = strbuf_detach(&buf, NULL);
+		s->should_free = 1;
 	}
 	return 0;
 }
@@ -2758,8 +2762,8 @@ int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
 	if (S_ISGITLINK(s->mode))
 		return diff_populate_gitlink(s, size_only);
 
-	if (!s->sha1_valid ||
-	    reuse_worktree_file(s->path, s->sha1, 0)) {
+	if (!s->oid_valid ||
+	    reuse_worktree_file(s->path, s->oid.hash, 0)) {
 		struct strbuf buf = STRBUF_INIT;
 		struct stat st;
 		int fd;
@@ -2816,9 +2820,10 @@ int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
 	else {
 		enum object_type type;
 		if (size_only || (flags & CHECK_BINARY)) {
-			type = sha1_object_info(s->sha1, &s->size);
+			type = sha1_object_info(s->oid.hash, &s->size);
 			if (type < 0)
-				die("unable to read %s", sha1_to_hex(s->sha1));
+				die("unable to read %s",
+				    oid_to_hex(&s->oid));
 			if (size_only)
 				return 0;
 			if (s->size > big_file_threshold && s->is_binary == -1) {
@@ -2826,9 +2831,9 @@ int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
 				return 0;
 			}
 		}
-		s->data = read_sha1_file(s->sha1, &type, &s->size);
+		s->data = read_sha1_file(s->oid.hash, &type, &s->size);
 		if (!s->data)
-			die("unable to read %s", sha1_to_hex(s->sha1));
+			die("unable to read %s", oid_to_hex(&s->oid));
 		s->should_free = 1;
 	}
 	return 0;
@@ -2857,7 +2862,7 @@ void diff_free_filespec_data(struct diff_filespec *s)
 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 			   void *blob,
 			   unsigned long size,
-			   const unsigned char *sha1,
+			   const struct object_id *oid,
 			   int mode)
 {
 	int fd;
@@ -2882,9 +2887,8 @@ static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
 		die_errno("unable to write temp-file");
 	close_tempfile(&temp->tempfile);
 	temp->name = get_tempfile_path(&temp->tempfile);
-	strcpy(temp->hex, sha1_to_hex(sha1));
-	temp->hex[40] = 0;
-	sprintf(temp->mode, "%06o", mode);
+	oid_to_hex_r(temp->hex, oid);
+	xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
 	strbuf_release(&buf);
 	strbuf_release(&template);
 	free(path_dup);
@@ -2901,14 +2905,14 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 		 * a '+' entry produces this for file-1.
 		 */
 		temp->name = "/dev/null";
-		strcpy(temp->hex, ".");
-		strcpy(temp->mode, ".");
+		xsnprintf(temp->hex, sizeof(temp->hex), ".");
+		xsnprintf(temp->mode, sizeof(temp->mode), ".");
 		return temp;
 	}
 
 	if (!S_ISGITLINK(one->mode) &&
-	    (!one->sha1_valid ||
-	     reuse_worktree_file(name, one->sha1, 1))) {
+	    (!one->oid_valid ||
+	     reuse_worktree_file(name, one->oid.hash, 1))) {
 		struct stat st;
 		if (lstat(name, &st) < 0) {
 			if (errno == ENOENT)
@@ -2920,26 +2924,26 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 			if (strbuf_readlink(&sb, name, st.st_size) < 0)
 				die_errno("readlink(%s)", name);
 			prep_temp_blob(name, temp, sb.buf, sb.len,
-				       (one->sha1_valid ?
-					one->sha1 : null_sha1),
-				       (one->sha1_valid ?
+				       (one->oid_valid ?
+					&one->oid : &null_oid),
+				       (one->oid_valid ?
 					one->mode : S_IFLNK));
 			strbuf_release(&sb);
 		}
 		else {
 			/* we can borrow from the file in the work tree */
 			temp->name = name;
-			if (!one->sha1_valid)
-				strcpy(temp->hex, sha1_to_hex(null_sha1));
+			if (!one->oid_valid)
+				sha1_to_hex_r(temp->hex, null_sha1);
 			else
-				strcpy(temp->hex, sha1_to_hex(one->sha1));
+				sha1_to_hex_r(temp->hex, one->oid.hash);
 			/* Even though we may sometimes borrow the
 			 * contents from the work tree, we always want
 			 * one->mode.  mode is trustworthy even when
 			 * !(one->sha1_valid), as long as
 			 * DIFF_FILE_VALID(one).
 			 */
-			sprintf(temp->mode, "%06o", one->mode);
+			xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
 		}
 		return temp;
 	}
@@ -2947,7 +2951,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 		if (diff_populate_filespec(one, 0))
 			die("cannot read data blob for %s", one->path);
 		prep_temp_blob(name, temp, one->data, one->size,
-			       one->sha1, one->mode);
+			       &one->oid, one->mode);
 	}
 	return temp;
 }
@@ -3060,7 +3064,7 @@ static void fill_metainfo(struct strbuf *msg,
 	default:
 		*must_show_header = 0;
 	}
-	if (one && two && hashcmp(one->sha1, two->sha1)) {
+	if (one && two && oidcmp(&one->oid, &two->oid)) {
 		int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 
 		if (DIFF_OPT_TST(o, BINARY)) {
@@ -3070,8 +3074,8 @@ static void fill_metainfo(struct strbuf *msg,
 				abbrev = 40;
 		}
 		strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
-			    find_unique_abbrev(one->sha1, abbrev));
-		strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
+			    find_unique_abbrev(one->oid.hash, abbrev));
+		strbuf_addstr(msg, find_unique_abbrev(two->oid.hash, abbrev));
 		if (one->mode == two->mode)
 			strbuf_addf(msg, " %06o", one->mode);
 		strbuf_addf(msg, "%s\n", reset);
@@ -3126,20 +3130,20 @@ static void run_diff_cmd(const char *pgm,
 static void diff_fill_sha1_info(struct diff_filespec *one)
 {
 	if (DIFF_FILE_VALID(one)) {
-		if (!one->sha1_valid) {
+		if (!one->oid_valid) {
 			struct stat st;
 			if (one->is_stdin) {
-				hashcpy(one->sha1, null_sha1);
+				oidclr(&one->oid);
 				return;
 			}
 			if (lstat(one->path, &st) < 0)
 				die_errno("stat '%s'", one->path);
-			if (index_path(one->sha1, one->path, &st, 0))
+			if (index_path(one->oid.hash, one->path, &st, 0))
 				die("cannot hash %s", one->path);
 		}
 	}
 	else
-		hashclr(one->sha1);
+		oidclr(&one->oid);
 }
 
 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
@@ -3278,6 +3282,8 @@ void diff_setup(struct diff_options *options)
 	options->use_color = diff_use_color_default;
 	options->detect_rename = diff_detect_rename_default;
 	options->xdl_opts |= diff_algorithm;
+	if (diff_compaction_heuristic)
+		DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
 
 	options->orderfile = diff_order_file_cfg;
 
@@ -3695,12 +3701,16 @@ static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
 	return 1;
 }
 
-int diff_opt_parse(struct diff_options *options, const char **av, int ac)
+int diff_opt_parse(struct diff_options *options,
+		   const char **av, int ac, const char *prefix)
 {
 	const char *arg = av[0];
 	const char *optarg;
 	int argcount;
 
+	if (!prefix)
+		prefix = "";
+
 	/* Output format options */
 	if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
 	    || opt_arg(arg, 'U', "unified", &options->context))
@@ -3794,6 +3804,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
 	else if (!strcmp(arg, "--ignore-blank-lines"))
 		DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
+	else if (!strcmp(arg, "--compaction-heuristic"))
+		DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
+	else if (!strcmp(arg, "--no-compaction-heuristic"))
+		DIFF_XDL_CLR(options, COMPACTION_HEURISTIC);
 	else if (!strcmp(arg, "--patience"))
 		options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
 	else if (!strcmp(arg, "--histogram"))
@@ -3917,7 +3931,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	else if (!strcmp(arg, "--pickaxe-regex"))
 		options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
 	else if ((argcount = short_opt('O', av, &optarg))) {
-		options->orderfile = optarg;
+		const char *path = prefix_filename(prefix, strlen(prefix), optarg);
+		options->orderfile = xstrdup(path);
 		return argcount;
 	}
 	else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
@@ -3956,10 +3971,13 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	else if (!strcmp(arg, "--no-function-context"))
 		DIFF_OPT_CLR(options, FUNCCONTEXT);
 	else if ((argcount = parse_long_opt("output", av, &optarg))) {
-		options->file = fopen(optarg, "w");
+		const char *path = prefix_filename(prefix, strlen(prefix), optarg);
+		options->file = fopen(path, "w");
 		if (!options->file)
-			die_errno("Could not open '%s'", optarg);
+			die_errno("Could not open '%s'", path);
 		options->close_file = 1;
+		if (options->use_color != GIT_COLOR_ALWAYS)
+			options->use_color = GIT_COLOR_NEVER;
 		return argcount;
 	} else
 		return 0;
@@ -4085,9 +4103,9 @@ const char *diff_unique_abbrev(const unsigned char *sha1, int len)
 	if (abblen < 37) {
 		static char hex[41];
 		if (len < abblen && abblen <= len + 2)
-			sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
+			xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
 		else
-			sprintf(hex, "%s...", abbrev);
+			xsnprintf(hex, sizeof(hex), "%s...", abbrev);
 		return hex;
 	}
 	return sha1_to_hex(sha1);
@@ -4101,8 +4119,9 @@ static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
 	fprintf(opt->file, "%s", diff_line_prefix(opt));
 	if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
 		fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
-			diff_unique_abbrev(p->one->sha1, opt->abbrev));
-		fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
+			diff_unique_abbrev(p->one->oid.hash, opt->abbrev));
+		fprintf(opt->file, "%s ",
+			diff_unique_abbrev(p->two->oid.hash, opt->abbrev));
 	}
 	if (p->score) {
 		fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
@@ -4151,11 +4170,11 @@ int diff_unmodified_pair(struct diff_filepair *p)
 	/* both are valid and point at the same path.  that is, we are
 	 * dealing with a change.
 	 */
-	if (one->sha1_valid && two->sha1_valid &&
-	    !hashcmp(one->sha1, two->sha1) &&
+	if (one->oid_valid && two->oid_valid &&
+	    !oidcmp(&one->oid, &two->oid) &&
 	    !one->dirty_submodule && !two->dirty_submodule)
 		return 1; /* no change */
-	if (!one->sha1_valid && !two->sha1_valid)
+	if (!one->oid_valid && !two->oid_valid)
 		return 1; /* both look at the same file on the filesystem. */
 	return 0;
 }
@@ -4216,7 +4235,7 @@ void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
 		s->path,
 		DIFF_FILE_VALID(s) ? "valid" : "invalid",
 		s->mode,
-		s->sha1_valid ? sha1_to_hex(s->sha1) : "");
+		s->oid_valid ? oid_to_hex(&s->oid) : "");
 	fprintf(stderr, "queue[%d] %s size %lu\n",
 		x, one ? one : "",
 		s->size);
@@ -4286,11 +4305,11 @@ static void diff_resolve_rename_copy(void)
 			else
 				p->status = DIFF_STATUS_RENAMED;
 		}
-		else if (hashcmp(p->one->sha1, p->two->sha1) ||
+		else if (oidcmp(&p->one->oid, &p->two->oid) ||
 			 p->one->mode != p->two->mode ||
 			 p->one->dirty_submodule ||
 			 p->two->dirty_submodule ||
-			 is_null_sha1(p->one->sha1))
+			 is_null_oid(&p->one->oid))
 			p->status = DIFF_STATUS_MODIFIED;
 		else {
 			/* This is a "no-change" entry and should not
@@ -4432,7 +4451,7 @@ static void patch_id_consume(void *priv, char *line, unsigned long len)
 }
 
 /* returns 0 upon success, and writes result into sha1 */
-static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
+static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
 {
 	struct diff_queue_struct *q = &diff_queued_diff;
 	int i;
@@ -4467,9 +4486,6 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 
 		diff_fill_sha1_info(p->one);
 		diff_fill_sha1_info(p->two);
-		if (fill_mmfile(&mf1, p->one) < 0 ||
-				fill_mmfile(&mf2, p->two) < 0)
-			return error("unable to read files to diff");
 
 		len1 = remove_space(p->one->path, strlen(p->one->path));
 		len2 = remove_space(p->two->path, strlen(p->two->path));
@@ -4504,10 +4520,19 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 					len2, p->two->path);
 		git_SHA1_Update(&ctx, buffer, len1);
 
+		if (diff_header_only)
+			continue;
+
+		if (fill_mmfile(&mf1, p->one) < 0 ||
+		    fill_mmfile(&mf2, p->two) < 0)
+			return error("unable to read files to diff");
+
 		if (diff_filespec_is_binary(p->one) ||
 		    diff_filespec_is_binary(p->two)) {
-			git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
-			git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
+			git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
+					40);
+			git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
+					40);
 			continue;
 		}
 
@@ -4524,11 +4549,11 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 	return 0;
 }
 
-int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
+int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
 {
 	struct diff_queue_struct *q = &diff_queued_diff;
 	int i;
-	int result = diff_get_patch_id(options, sha1);
+	int result = diff_get_patch_id(options, sha1, diff_header_only);
 
 	for (i = 0; i < q->nr; i++)
 		diff_free_filepair(q->queue[i]);
@@ -4799,7 +4824,7 @@ static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
 	 */
 	if (!DIFF_FILE_VALID(p->one) || /* (1) */
 	    !DIFF_FILE_VALID(p->two) ||
-	    (p->one->sha1_valid && p->two->sha1_valid) ||
+	    (p->one->oid_valid && p->two->oid_valid) ||
 	    (p->one->mode != p->two->mode) ||
 	    diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
 	    diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
@@ -5081,7 +5106,7 @@ size_t fill_textconv(struct userdiff_driver *driver,
 {
 	size_t size;
 
-	if (!driver || !driver->textconv) {
+	if (!driver) {
 		if (!DIFF_FILE_VALID(df)) {
 			*outbuf = "";
 			return 0;
@@ -5092,8 +5117,12 @@ size_t fill_textconv(struct userdiff_driver *driver,
 		return df->size;
 	}
 
-	if (driver->textconv_cache && df->sha1_valid) {
-		*outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
+	if (!driver->textconv)
+		die("BUG: fill_textconv called with non-textconv driver");
+
+	if (driver->textconv_cache && df->oid_valid) {
+		*outbuf = notes_cache_get(driver->textconv_cache,
+					  df->oid.hash,
 					  &size);
 		if (*outbuf)
 			return size;
@@ -5103,9 +5132,9 @@ size_t fill_textconv(struct userdiff_driver *driver,
 	if (!*outbuf)
 		die("unable to read files to diff");
 
-	if (driver->textconv_cache && df->sha1_valid) {
+	if (driver->textconv_cache && df->oid_valid) {
 		/* ignore errors, as we might be in a readonly repository */
-		notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
+		notes_cache_put(driver->textconv_cache, df->oid.hash, *outbuf,
 				size);
 		/*
 		 * we could save up changes and flush them all at the end,