merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 256 insertions, 159 deletions

diff --git a/third_party/git/diff.c b/third_party/git/diff.c
index efe42b341ae1..2bb2f8f57e8b 100644
--- a/third_party/git/diff.c
+++ b/third_party/git/diff.c
@@ -20,12 +20,12 @@
 #include "hashmap.h"
 #include "ll-merge.h"
 #include "string-list.h"
-#include "argv-array.h"
+#include "strvec.h"
 #include "graph.h"
 #include "packfile.h"
 #include "parse-options.h"
 #include "help.h"
-#include "fetch-object.h"
+#include "promisor-remote.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -48,6 +48,7 @@ static const char *diff_order_file_cfg;
 int diff_auto_refresh_index = 1;
 static int diff_mnemonic_prefix;
 static int diff_no_prefix;
+static int diff_relative;
 static int diff_stat_graph_width;
 static int diff_dirstat_permille_default = 30;
 static struct diff_options default_diff_options;
@@ -386,6 +387,10 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		diff_no_prefix = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "diff.relative")) {
+		diff_relative = git_config_bool(var, value);
+		return 0;
+	}
 	if (!strcmp(var, "diff.statgraphwidth")) {
 		diff_stat_graph_width = git_config_int(var, value);
 		return 0;
@@ -414,14 +419,6 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
-	if (!strcmp(var, "diff.wserrorhighlight")) {
-		int val = parse_ws_error_highlight(value);
-		if (val < 0)
-			return -1;
-		ws_error_highlight_default = val;
-		return 0;
-	}
-
 	if (git_color_config(var, value, cb) < 0)
 		return -1;
 
@@ -450,6 +447,14 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 		return color_parse(value, diff_colors[slot]);
 	}
 
+	if (!strcmp(var, "diff.wserrorhighlight")) {
+		int val = parse_ws_error_highlight(value);
+		if (val < 0)
+			return -1;
+		ws_error_highlight_default = val;
+		return 0;
+	}
+
 	/* like GNU diff's --suppress-blank-empty option  */
 	if (!strcmp(var, "diff.suppressblankempty") ||
 			/* for backwards compatibility */
@@ -477,14 +482,14 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 
 static char *quote_two(const char *one, const char *two)
 {
-	int need_one = quote_c_style(one, NULL, NULL, 1);
-	int need_two = quote_c_style(two, NULL, NULL, 1);
+	int need_one = quote_c_style(one, NULL, NULL, CQUOTE_NODQ);
+	int need_two = quote_c_style(two, NULL, NULL, CQUOTE_NODQ);
 	struct strbuf res = STRBUF_INIT;
 
 	if (need_one + need_two) {
 		strbuf_addch(&res, '"');
-		quote_c_style(one, &res, NULL, 1);
-		quote_c_style(two, &res, NULL, 1);
+		quote_c_style(one, &res, NULL, CQUOTE_NODQ);
+		quote_c_style(two, &res, NULL, CQUOTE_NODQ);
 		strbuf_addch(&res, '"');
 	} else {
 		strbuf_addstr(&res, one);
@@ -573,7 +578,7 @@ static int fill_mmfile(struct repository *r, mmfile_t *mf,
 		mf->size = 0;
 		return 0;
 	}
-	else if (diff_populate_filespec(r, one, 0))
+	else if (diff_populate_filespec(r, one, NULL))
 		return -1;
 
 	mf->ptr = one->data;
@@ -585,9 +590,13 @@ static int fill_mmfile(struct repository *r, mmfile_t *mf,
 static unsigned long diff_filespec_size(struct repository *r,
 					struct diff_filespec *one)
 {
+	struct diff_populate_filespec_options dpf_options = {
+		.check_size_only = 1,
+	};
+
 	if (!DIFF_FILE_VALID(one))
 		return 0;
-	diff_populate_filespec(r, one, CHECK_SIZE_ONLY);
+	diff_populate_filespec(r, one, &dpf_options);
 	return one->size;
 }
 
@@ -933,16 +942,18 @@ static int cmp_in_block_with_wsd(const struct diff_options *o,
 }
 
 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
-			   const void *entry,
-			   const void *entry_or_key,
+			   const struct hashmap_entry *eptr,
+			   const struct hashmap_entry *entry_or_key,
 			   const void *keydata)
 {
 	const struct diff_options *diffopt = hashmap_cmp_fn_data;
-	const struct moved_entry *a = entry;
-	const struct moved_entry *b = entry_or_key;
+	const struct moved_entry *a, *b;
 	unsigned flags = diffopt->color_moved_ws_handling
 			 & XDF_WHITESPACE_FLAGS;
 
+	a = container_of(eptr, const struct moved_entry, ent);
+	b = container_of(entry_or_key, const struct moved_entry, ent);
+
 	if (diffopt->color_moved_ws_handling &
 	    COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 		/*
@@ -964,8 +975,9 @@ static struct moved_entry *prepare_entry(struct diff_options *o,
 	struct moved_entry *ret = xmalloc(sizeof(*ret));
 	struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 	unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
+	unsigned int hash = xdiff_hash_string(l->line, l->len, flags);
 
-	ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
+	hashmap_entry_init(&ret->ent, hash);
 	ret->es = l;
 	ret->next_line = NULL;
 
@@ -1002,7 +1014,7 @@ static void add_lines_to_move_detection(struct diff_options *o,
 		if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 			prev_line->next_line = key;
 
-		hashmap_add(hm, key);
+		hashmap_add(hm, &key->ent);
 		prev_line = key;
 	}
 }
@@ -1018,7 +1030,7 @@ static void pmb_advance_or_null(struct diff_options *o,
 		struct moved_entry *prev = pmb[i].match;
 		struct moved_entry *cur = (prev && prev->next_line) ?
 				prev->next_line : NULL;
-		if (cur && !hm->cmpfn(o, cur, match, NULL)) {
+		if (cur && !hm->cmpfn(o, &cur->ent, &match->ent, NULL)) {
 			pmb[i].match = cur;
 		} else {
 			pmb[i].match = NULL;
@@ -1035,7 +1047,7 @@ static void pmb_advance_or_null_multi_match(struct diff_options *o,
 	int i;
 	char *got_match = xcalloc(1, pmb_nr);
 
-	for (; match; match = hashmap_get_next(hm, match)) {
+	hashmap_for_each_entry_from(hm, match, ent) {
 		for (i = 0; i < pmb_nr; i++) {
 			struct moved_entry *prev = pmb[i].match;
 			struct moved_entry *cur = (prev && prev->next_line) ?
@@ -1143,13 +1155,13 @@ static void mark_color_as_moved(struct diff_options *o,
 		case DIFF_SYMBOL_PLUS:
 			hm = del_lines;
 			key = prepare_entry(o, n);
-			match = hashmap_get(hm, key, NULL);
+			match = hashmap_get_entry(hm, key, ent, NULL);
 			free(key);
 			break;
 		case DIFF_SYMBOL_MINUS:
 			hm = add_lines;
 			key = prepare_entry(o, n);
-			match = hashmap_get(hm, key, NULL);
+			match = hashmap_get_entry(hm, key, ent, NULL);
 			free(key);
 			break;
 		default:
@@ -1188,7 +1200,7 @@ static void mark_color_as_moved(struct diff_options *o,
 			 * The current line is the start of a new block.
 			 * Setup the set of potential blocks.
 			 */
-			for (; match; match = hashmap_get_next(hm, match)) {
+			hashmap_for_each_entry_from(hm, match, ent) {
 				ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
 				if (o->color_moved_ws_handling &
 				    COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
@@ -2492,22 +2504,6 @@ static void pprint_rename(struct strbuf *name, const char *a, const char *b)
 	}
 }
 
-struct diffstat_t {
-	int nr;
-	int alloc;
-	struct diffstat_file {
-		char *from_name;
-		char *name;
-		char *print_name;
-		const char *comments;
-		unsigned is_unmerged:1;
-		unsigned is_binary:1;
-		unsigned is_renamed:1;
-		unsigned is_interesting:1;
-		uintmax_t added, deleted;
-	} **files;
-};
-
 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 					  const char *name_a,
 					  const char *name_b)
@@ -2548,7 +2544,7 @@ static int scale_linear(int it, int width, int max_change)
 	/*
 	 * make sure that at least one '-' or '+' is printed if
 	 * there is any change to this path. The easiest way is to
-	 * scale linearly as if the alloted width is one column shorter
+	 * scale linearly as if the allotted width is one column shorter
 	 * than it is, and then add 1 to the result.
 	 */
 	return 1 + (it * (width - 1) / max_change);
@@ -3033,6 +3029,9 @@ static void show_dirstat(struct diff_options *options)
 		struct diff_filepair *p = q->queue[i];
 		const char *name;
 		unsigned long copied, added, damage;
+		struct diff_populate_filespec_options dpf_options = {
+			.check_size_only = 1,
+		};
 
 		name = p->two->path ? p->two->path : p->one->path;
 
@@ -3060,19 +3059,19 @@ static void show_dirstat(struct diff_options *options)
 		}
 
 		if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
-			diff_populate_filespec(options->repo, p->one, 0);
-			diff_populate_filespec(options->repo, p->two, 0);
+			diff_populate_filespec(options->repo, p->one, NULL);
+			diff_populate_filespec(options->repo, p->two, NULL);
 			diffcore_count_changes(options->repo,
 					       p->one, p->two, NULL, NULL,
 					       &copied, &added);
 			diff_free_filespec_data(p->one);
 			diff_free_filespec_data(p->two);
 		} else if (DIFF_FILE_VALID(p->one)) {
-			diff_populate_filespec(options->repo, p->one, CHECK_SIZE_ONLY);
+			diff_populate_filespec(options->repo, p->one, &dpf_options);
 			copied = added = 0;
 			diff_free_filespec_data(p->one);
 		} else if (DIFF_FILE_VALID(p->two)) {
-			diff_populate_filespec(options->repo, p->two, CHECK_SIZE_ONLY);
+			diff_populate_filespec(options->repo, p->two, &dpf_options);
 			copied = 0;
 			added = p->two->size;
 			diff_free_filespec_data(p->two);
@@ -3154,16 +3153,19 @@ static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *o
 	gather_dirstat(options, &dir, changed, "", 0);
 }
 
-static void free_diffstat_info(struct diffstat_t *diffstat)
+static void free_diffstat_file(struct diffstat_file *f)
+{
+	free(f->print_name);
+	free(f->name);
+	free(f->from_name);
+	free(f);
+}
+
+void free_diffstat_info(struct diffstat_t *diffstat)
 {
 	int i;
-	for (i = 0; i < diffstat->nr; i++) {
-		struct diffstat_file *f = diffstat->files[i];
-		free(f->print_name);
-		free(f->name);
-		free(f->from_name);
-		free(f);
-	}
+	for (i = 0; i < diffstat->nr; i++)
+		free_diffstat_file(diffstat->files[i]);
 	free(diffstat->files);
 }
 
@@ -3193,7 +3195,7 @@ static int is_conflict_marker(const char *line, int marker_size, unsigned long l
 	for (cnt = 1; cnt < marker_size; cnt++)
 		if (line[cnt] != firstchar)
 			return 0;
-	/* line[1] thru line[marker_size-1] are same as firstchar */
+	/* line[1] through line[marker_size-1] are same as firstchar */
 	if (len < marker_size + 1 || !isspace(line[marker_size]))
 		return 0;
 	return 1;
@@ -3352,13 +3354,17 @@ static void emit_binary_diff(struct diff_options *o,
 int diff_filespec_is_binary(struct repository *r,
 			    struct diff_filespec *one)
 {
+	struct diff_populate_filespec_options dpf_options = {
+		.check_binary = 1,
+	};
+
 	if (one->is_binary == -1) {
 		diff_filespec_load_driver(one, r->index);
 		if (one->driver->binary != -1)
 			one->is_binary = one->driver->binary;
 		else {
 			if (!one->data && DIFF_FILE_VALID(one))
-				diff_populate_filespec(r, one, CHECK_BINARY);
+				diff_populate_filespec(r, one, &dpf_options);
 			if (one->is_binary == -1 && one->data)
 				one->is_binary = buffer_is_binary(one->data,
 						one->size);
@@ -3426,7 +3432,7 @@ static void builtin_diff(const char *name_a,
 	if (o->submodule_format == DIFF_SUBMODULE_LOG &&
 	    (!one->mode || S_ISGITLINK(one->mode)) &&
 	    (!two->mode || S_ISGITLINK(two->mode))) {
-		show_submodule_summary(o, one->path ? one->path : two->path,
+		show_submodule_diff_summary(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
 		return;
@@ -3657,7 +3663,7 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 {
 	mmfile_t mf1, mf2;
 	struct diffstat_file *data;
-	int same_contents;
+	int may_differ;
 	int complete_rewrite = 0;
 
 	if (!DIFF_PAIR_UNMERGED(p)) {
@@ -3675,12 +3681,14 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		return;
 	}
 
-	same_contents = oideq(&one->oid, &two->oid);
+	/* saves some reads if true, not a guarantee of diff outcome */
+	may_differ = !(one->oid_valid && two->oid_valid &&
+			oideq(&one->oid, &two->oid));
 
 	if (diff_filespec_is_binary(o->repo, one) ||
 	    diff_filespec_is_binary(o->repo, two)) {
 		data->is_binary = 1;
-		if (same_contents) {
+		if (!may_differ) {
 			data->added = 0;
 			data->deleted = 0;
 		} else {
@@ -3690,13 +3698,13 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 	}
 
 	else if (complete_rewrite) {
-		diff_populate_filespec(o->repo, one, 0);
-		diff_populate_filespec(o->repo, two, 0);
+		diff_populate_filespec(o->repo, one, NULL);
+		diff_populate_filespec(o->repo, two, NULL);
 		data->deleted = count_lines(one->data, one->size);
 		data->added = count_lines(two->data, two->size);
 	}
 
-	else if (!same_contents) {
+	else if (may_differ) {
 		/* Crazy xdl interfaces.. */
 		xpparam_t xpp;
 		xdemitconf_t xecfg;
@@ -3715,6 +3723,27 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
 				  diffstat_consume, diffstat, &xpp, &xecfg))
 			die("unable to generate diffstat for %s", one->path);
+
+		if (DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two)) {
+			struct diffstat_file *file =
+				diffstat->files[diffstat->nr - 1];
+			/*
+			 * Omit diffstats of modified files where nothing changed.
+			 * Even if may_differ, this might be the case due to
+			 * ignoring whitespace changes, etc.
+			 *
+			 * But note that we special-case additions, deletions,
+			 * renames, and mode changes as adding an empty file,
+			 * for example is still of interest.
+			 */
+			if ((p->status == DIFF_STATUS_MODIFIED)
+				&& !file->added
+				&& !file->deleted
+				&& one->mode == two->mode) {
+				free_diffstat_file(file);
+				diffstat->nr--;
+			}
+		}
 	}
 
 	diff_free_filespec_data(one);
@@ -3927,9 +3956,10 @@ static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
  */
 int diff_populate_filespec(struct repository *r,
 			   struct diff_filespec *s,
-			   unsigned int flags)
+			   const struct diff_populate_filespec_options *options)
 {
-	int size_only = flags & CHECK_SIZE_ONLY;
+	int size_only = options ? options->check_size_only : 0;
+	int check_binary = options ? options->check_binary : 0;
 	int err = 0;
 	int conv_flags = global_conv_flags_eol;
 	/*
@@ -3999,7 +4029,7 @@ int diff_populate_filespec(struct repository *r,
 		 * opening the file and inspecting the contents, this
 		 * is probably fine.
 		 */
-		if ((flags & CHECK_BINARY) &&
+		if (check_binary &&
 		    s->size > big_file_threshold && s->is_binary == -1) {
 			s->is_binary = 1;
 			return 0;
@@ -4024,12 +4054,30 @@ int diff_populate_filespec(struct repository *r,
 		}
 	}
 	else {
-		enum object_type type;
-		if (size_only || (flags & CHECK_BINARY)) {
-			type = oid_object_info(r, &s->oid, &s->size);
-			if (type < 0)
-				die("unable to read %s",
-				    oid_to_hex(&s->oid));
+		struct object_info info = {
+			.sizep = &s->size
+		};
+
+		if (!(size_only || check_binary))
+			/*
+			 * Set contentp, since there is no chance that merely
+			 * the size is sufficient.
+			 */
+			info.contentp = &s->data;
+
+		if (options && options->missing_object_cb) {
+			if (!oid_object_info_extended(r, &s->oid, &info,
+						      OBJECT_INFO_LOOKUP_REPLACE |
+						      OBJECT_INFO_SKIP_FETCH_OBJECT))
+				goto object_read;
+			options->missing_object_cb(options->missing_object_data);
+		}
+		if (oid_object_info_extended(r, &s->oid, &info,
+					     OBJECT_INFO_LOOKUP_REPLACE))
+			die("unable to read %s", oid_to_hex(&s->oid));
+
+object_read:
+		if (size_only || check_binary) {
 			if (size_only)
 				return 0;
 			if (s->size > big_file_threshold && s->is_binary == -1) {
@@ -4037,9 +4085,12 @@ int diff_populate_filespec(struct repository *r,
 				return 0;
 			}
 		}
-		s->data = read_object_file(&s->oid, &type, &s->size);
-		if (!s->data)
-			die("unable to read %s", oid_to_hex(&s->oid));
+		if (!info.contentp) {
+			info.contentp = &s->data;
+			if (oid_object_info_extended(r, &s->oid, &info,
+						     OBJECT_INFO_LOOKUP_REPLACE))
+				die("unable to read %s", oid_to_hex(&s->oid));
+		}
 		s->should_free = 1;
 	}
 	return 0;
@@ -4075,6 +4126,9 @@ static void prep_temp_blob(struct index_state *istate,
 	struct strbuf tempfile = STRBUF_INIT;
 	char *path_dup = xstrdup(path);
 	const char *base = basename(path_dup);
+	struct checkout_metadata meta;
+
+	init_checkout_metadata(&meta, NULL, NULL, oid);
 
 	/* Generate "XXXXXX_basename.ext" */
 	strbuf_addstr(&tempfile, "XXXXXX_");
@@ -4084,7 +4138,7 @@ static void prep_temp_blob(struct index_state *istate,
 	if (!temp->tempfile)
 		die_errno("unable to create temp-file");
 	if (convert_to_working_tree(istate, path,
-			(const char *)blob, (size_t)size, &buf)) {
+			(const char *)blob, (size_t)size, &buf, &meta)) {
 		blob = buf.buf;
 		size = buf.len;
 	}
@@ -4154,7 +4208,7 @@ static struct diff_tempfile *prepare_temp_file(struct repository *r,
 		return temp;
 	}
 	else {
-		if (diff_populate_filespec(r, one, 0))
+		if (diff_populate_filespec(r, one, NULL))
 			die("cannot read data blob for %s", one->path);
 		prep_temp_blob(r->index, name, temp,
 			       one->data, one->size,
@@ -4164,14 +4218,14 @@ static struct diff_tempfile *prepare_temp_file(struct repository *r,
 }
 
 static void add_external_diff_name(struct repository *r,
-				   struct argv_array *argv,
+				   struct strvec *argv,
 				   const char *name,
 				   struct diff_filespec *df)
 {
 	struct diff_tempfile *temp = prepare_temp_file(r, name, df);
-	argv_array_push(argv, temp->name);
-	argv_array_push(argv, temp->hex);
-	argv_array_push(argv, temp->mode);
+	strvec_push(argv, temp->name);
+	strvec_push(argv, temp->hex);
+	strvec_push(argv, temp->mode);
 }
 
 /* An external diff command takes:
@@ -4188,12 +4242,12 @@ static void run_external_diff(const char *pgm,
 			      const char *xfrm_msg,
 			      struct diff_options *o)
 {
-	struct argv_array argv = ARGV_ARRAY_INIT;
-	struct argv_array env = ARGV_ARRAY_INIT;
+	struct strvec argv = STRVEC_INIT;
+	struct strvec env = STRVEC_INIT;
 	struct diff_queue_struct *q = &diff_queued_diff;
 
-	argv_array_push(&argv, pgm);
-	argv_array_push(&argv, name);
+	strvec_push(&argv, pgm);
+	strvec_push(&argv, name);
 
 	if (one && two) {
 		add_external_diff_name(o->repo, &argv, name, one);
@@ -4201,22 +4255,22 @@ static void run_external_diff(const char *pgm,
 			add_external_diff_name(o->repo, &argv, name, two);
 		else {
 			add_external_diff_name(o->repo, &argv, other, two);
-			argv_array_push(&argv, other);
-			argv_array_push(&argv, xfrm_msg);
+			strvec_push(&argv, other);
+			strvec_push(&argv, xfrm_msg);
 		}
 	}
 
-	argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
-	argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
+	strvec_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
+	strvec_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
 
 	diff_free_filespec_data(one);
 	diff_free_filespec_data(two);
-	if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
+	if (run_command_v_opt_cd_env(argv.v, RUN_USING_SHELL, NULL, env.v))
 		die(_("external diff died, stopping at %s"), name);
 
 	remove_tempfile();
-	argv_array_clear(&argv);
-	argv_array_clear(&env);
+	strvec_clear(&argv);
+	strvec_clear(&env);
 }
 
 static int similarity_index(struct diff_filepair *p)
@@ -4291,7 +4345,10 @@ static void fill_metainfo(struct strbuf *msg,
 	}
 	if (one && two && !oideq(&one->oid, &two->oid)) {
 		const unsigned hexsz = the_hash_algo->hexsz;
-		int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
+		int abbrev = o->abbrev ? o->abbrev : DEFAULT_ABBREV;
+
+		if (o->flags.full_index)
+			abbrev = hexsz;
 
 		if (o->flags.binary) {
 			mmfile_t mf;
@@ -4515,6 +4572,7 @@ void repo_diff_setup(struct repository *r, struct diff_options *options)
 	options->interhunkcontext = diff_interhunk_context_default;
 	options->ws_error_highlight = ws_error_highlight_default;
 	options->flags.rename_empty = 1;
+	options->flags.relative_name = diff_relative;
 	options->objfind = NULL;
 
 	/* pathchange left =NULL by default */
@@ -5172,8 +5230,7 @@ static int diff_opt_relative(const struct option *opt,
 {
 	struct diff_options *options = opt->value;
 
-	BUG_ON_OPT_NEG(unset);
-	options->flags.relative_name = 1;
+	options->flags.relative_name = !unset;
 	if (arg)
 		options->prefix = arg;
 	return 0;
@@ -5469,7 +5526,7 @@ static void prep_parse_options(struct diff_options *options)
 		OPT_GROUP(N_("Other diff options")),
 		OPT_CALLBACK_F(0, "relative", options, N_("<prefix>"),
 			       N_("when run from subdir, exclude changes outside and show relative paths"),
-			       PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
+			       PARSE_OPT_OPTARG,
 			       diff_opt_relative),
 		OPT_BOOL('a', "text", &options->flags.text,
 			 N_("treat all files as text")),
@@ -5978,7 +6035,7 @@ static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
 }
 
 struct patch_id_t {
-	git_SHA_CTX *ctx;
+	git_hash_ctx *ctx;
 	int patchlen;
 };
 
@@ -5995,16 +6052,16 @@ static int remove_space(char *line, int len)
 	return dst - line;
 }
 
-void flush_one_hunk(struct object_id *result, git_SHA_CTX *ctx)
+void flush_one_hunk(struct object_id *result, git_hash_ctx *ctx)
 {
 	unsigned char hash[GIT_MAX_RAWSZ];
 	unsigned short carry = 0;
 	int i;
 
-	git_SHA1_Final(hash, ctx);
-	git_SHA1_Init(ctx);
+	the_hash_algo->final_fn(hash, ctx);
+	the_hash_algo->init_fn(ctx);
 	/* 20-byte sum, with carry */
-	for (i = 0; i < GIT_SHA1_RAWSZ; ++i) {
+	for (i = 0; i < the_hash_algo->rawsz; ++i) {
 		carry += result->hash[i] + hash[i];
 		result->hash[i] = carry;
 		carry >>= 8;
@@ -6016,23 +6073,25 @@ static void patch_id_consume(void *priv, char *line, unsigned long len)
 	struct patch_id_t *data = priv;
 	int new_len;
 
+	if (len > 12 && starts_with(line, "\\ "))
+		return;
 	new_len = remove_space(line, len);
 
-	git_SHA1_Update(data->ctx, line, new_len);
+	the_hash_algo->update_fn(data->ctx, line, new_len);
 	data->patchlen += new_len;
 }
 
-static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
+static void patch_id_add_string(git_hash_ctx *ctx, const char *str)
 {
-	git_SHA1_Update(ctx, str, strlen(str));
+	the_hash_algo->update_fn(ctx, str, strlen(str));
 }
 
-static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
+static void patch_id_add_mode(git_hash_ctx *ctx, unsigned mode)
 {
 	/* large enough for 2^32 in octal */
 	char buf[12];
 	int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
-	git_SHA1_Update(ctx, buf, len);
+	the_hash_algo->update_fn(ctx, buf, len);
 }
 
 /* returns 0 upon success, and writes result into oid */
@@ -6040,10 +6099,10 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
 {
 	struct diff_queue_struct *q = &diff_queued_diff;
 	int i;
-	git_SHA_CTX ctx;
+	git_hash_ctx ctx;
 	struct patch_id_t data;
 
-	git_SHA1_Init(&ctx);
+	the_hash_algo->init_fn(&ctx);
 	memset(&data, 0, sizeof(struct patch_id_t));
 	data.ctx = &ctx;
 	oidclr(oid);
@@ -6076,27 +6135,27 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
 		len2 = remove_space(p->two->path, strlen(p->two->path));
 		patch_id_add_string(&ctx, "diff--git");
 		patch_id_add_string(&ctx, "a/");
-		git_SHA1_Update(&ctx, p->one->path, len1);
+		the_hash_algo->update_fn(&ctx, p->one->path, len1);
 		patch_id_add_string(&ctx, "b/");
-		git_SHA1_Update(&ctx, p->two->path, len2);
+		the_hash_algo->update_fn(&ctx, p->two->path, len2);
 
 		if (p->one->mode == 0) {
 			patch_id_add_string(&ctx, "newfilemode");
 			patch_id_add_mode(&ctx, p->two->mode);
 			patch_id_add_string(&ctx, "---/dev/null");
 			patch_id_add_string(&ctx, "+++b/");
-			git_SHA1_Update(&ctx, p->two->path, len2);
+			the_hash_algo->update_fn(&ctx, p->two->path, len2);
 		} else if (p->two->mode == 0) {
 			patch_id_add_string(&ctx, "deletedfilemode");
 			patch_id_add_mode(&ctx, p->one->mode);
 			patch_id_add_string(&ctx, "---a/");
-			git_SHA1_Update(&ctx, p->one->path, len1);
+			the_hash_algo->update_fn(&ctx, p->one->path, len1);
 			patch_id_add_string(&ctx, "+++/dev/null");
 		} else {
 			patch_id_add_string(&ctx, "---a/");
-			git_SHA1_Update(&ctx, p->one->path, len1);
+			the_hash_algo->update_fn(&ctx, p->one->path, len1);
 			patch_id_add_string(&ctx, "+++b/");
-			git_SHA1_Update(&ctx, p->two->path, len2);
+			the_hash_algo->update_fn(&ctx, p->two->path, len2);
 		}
 
 		if (diff_header_only)
@@ -6108,10 +6167,10 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
 
 		if (diff_filespec_is_binary(options->repo, p->one) ||
 		    diff_filespec_is_binary(options->repo, p->two)) {
-			git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
-					GIT_SHA1_HEXSZ);
-			git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
-					GIT_SHA1_HEXSZ);
+			the_hash_algo->update_fn(&ctx, oid_to_hex(&p->one->oid),
+					the_hash_algo->hexsz);
+			the_hash_algo->update_fn(&ctx, oid_to_hex(&p->two->oid),
+					the_hash_algo->hexsz);
 			continue;
 		}
 
@@ -6128,7 +6187,7 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
 	}
 
 	if (!stable)
-		git_SHA1_Final(oid->hash, &ctx);
+		the_hash_algo->final_fn(oid->hash, &ctx);
 
 	return 0;
 }
@@ -6230,8 +6289,10 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
 			if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
 				dim_moved_lines(o);
 
-			hashmap_free(&add_lines, 1);
-			hashmap_free(&del_lines, 1);
+			hashmap_free_entries(&add_lines, struct moved_entry,
+						ent);
+			hashmap_free_entries(&del_lines, struct moved_entry,
+						ent);
 		}
 
 		for (i = 0; i < esm.nr; i++)
@@ -6278,12 +6339,7 @@ void diff_flush(struct diff_options *options)
 	    dirstat_by_line) {
 		struct diffstat_t diffstat;
 
-		memset(&diffstat, 0, sizeof(struct diffstat_t));
-		for (i = 0; i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-			if (check_pair_status(p))
-				diff_flush_stat(p, options, &diffstat);
-		}
+		compute_diffstat(options, &diffstat, q);
 		if (output_format & DIFF_FORMAT_NUMSTAT)
 			show_numstat(&diffstat, options);
 		if (output_format & DIFF_FORMAT_DIFFSTAT)
@@ -6423,9 +6479,9 @@ static int diff_filespec_is_identical(struct repository *r,
 {
 	if (S_ISGITLINK(one->mode))
 		return 0;
-	if (diff_populate_filespec(r, one, 0))
+	if (diff_populate_filespec(r, one, NULL))
 		return 0;
-	if (diff_populate_filespec(r, two, 0))
+	if (diff_populate_filespec(r, two, NULL))
 		return 0;
 	return !memcmp(one->data, two->data, one->size);
 }
@@ -6433,6 +6489,12 @@ static int diff_filespec_is_identical(struct repository *r,
 static int diff_filespec_check_stat_unmatch(struct repository *r,
 					    struct diff_filepair *p)
 {
+	struct diff_populate_filespec_options dpf_options = {
+		.check_size_only = 1,
+		.missing_object_cb = diff_queued_diff_prefetch,
+		.missing_object_data = r,
+	};
+
 	if (p->done_skip_stat_unmatch)
 		return p->skip_stat_unmatch_result;
 
@@ -6455,8 +6517,8 @@ static int diff_filespec_check_stat_unmatch(struct repository *r,
 	    !DIFF_FILE_VALID(p->two) ||
 	    (p->one->oid_valid && p->two->oid_valid) ||
 	    (p->one->mode != p->two->mode) ||
-	    diff_populate_filespec(r, p->one, CHECK_SIZE_ONLY) ||
-	    diff_populate_filespec(r, p->two, CHECK_SIZE_ONLY) ||
+	    diff_populate_filespec(r, p->one, &dpf_options) ||
+	    diff_populate_filespec(r, p->two, &dpf_options) ||
 	    (p->one->size != p->two->size) ||
 	    !diff_filespec_is_identical(r, p->one, p->two)) /* (2) */
 		p->skip_stat_unmatch_result = 1;
@@ -6507,41 +6569,59 @@ void diffcore_fix_diff_index(void)
 	QSORT(q->queue, q->nr, diffnamecmp);
 }
 
-static void add_if_missing(struct repository *r,
-			   struct oid_array *to_fetch,
-			   const struct diff_filespec *filespec)
+void diff_add_if_missing(struct repository *r,
+			 struct oid_array *to_fetch,
+			 const struct diff_filespec *filespec)
 {
 	if (filespec && filespec->oid_valid &&
+	    !S_ISGITLINK(filespec->mode) &&
 	    oid_object_info_extended(r, &filespec->oid, NULL,
 				     OBJECT_INFO_FOR_PREFETCH))
 		oid_array_append(to_fetch, &filespec->oid);
 }
 
-void diffcore_std(struct diff_options *options)
+void diff_queued_diff_prefetch(void *repository)
 {
-	if (options->repo == the_repository &&
-	    repository_format_partial_clone) {
-		/*
-		 * Prefetch the diff pairs that are about to be flushed.
-		 */
-		int i;
-		struct diff_queue_struct *q = &diff_queued_diff;
-		struct oid_array to_fetch = OID_ARRAY_INIT;
+	struct repository *repo = repository;
+	int i;
+	struct diff_queue_struct *q = &diff_queued_diff;
+	struct oid_array to_fetch = OID_ARRAY_INIT;
 
-		for (i = 0; i < q->nr; i++) {
-			struct diff_filepair *p = q->queue[i];
-			add_if_missing(options->repo, &to_fetch, p->one);
-			add_if_missing(options->repo, &to_fetch, p->two);
-		}
-		if (to_fetch.nr)
-			/*
-			 * NEEDSWORK: Consider deduplicating the OIDs sent.
-			 */
-			fetch_objects(repository_format_partial_clone,
-				      to_fetch.oid, to_fetch.nr);
-		oid_array_clear(&to_fetch);
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+		diff_add_if_missing(repo, &to_fetch, p->one);
+		diff_add_if_missing(repo, &to_fetch, p->two);
 	}
 
+	/*
+	 * NEEDSWORK: Consider deduplicating the OIDs sent.
+	 */
+	promisor_remote_get_direct(repo, to_fetch.oid, to_fetch.nr);
+
+	oid_array_clear(&to_fetch);
+}
+
+void diffcore_std(struct diff_options *options)
+{
+	int output_formats_to_prefetch = DIFF_FORMAT_DIFFSTAT |
+		DIFF_FORMAT_NUMSTAT |
+		DIFF_FORMAT_PATCH |
+		DIFF_FORMAT_SHORTSTAT |
+		DIFF_FORMAT_DIRSTAT;
+
+	/*
+	 * Check if the user requested a blob-data-requiring diff output and/or
+	 * break-rewrite detection (which requires blob data). If yes, prefetch
+	 * the diff pairs.
+	 *
+	 * If no prefetching occurs, diffcore_rename() will prefetch if it
+	 * decides that it needs inexact rename detection.
+	 */
+	if (options->repo == the_repository && has_promisor_remote() &&
+	    (options->output_format & output_formats_to_prefetch ||
+	     options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
+		diff_queued_diff_prefetch(options->repo);
+
 	/* NOTE please keep the following in sync with diff_tree_combined() */
 	if (options->skip_stat_unmatch)
 		diffcore_skip_stat_unmatch(options);
@@ -6616,6 +6696,20 @@ static int is_submodule_ignored(const char *path, struct diff_options *options)
 	return ignored;
 }
 
+void compute_diffstat(struct diff_options *options,
+		      struct diffstat_t *diffstat,
+		      struct diff_queue_struct *q)
+{
+	int i;
+
+	memset(diffstat, 0, sizeof(struct diffstat_t));
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+		if (check_pair_status(p))
+			diff_flush_stat(p, options, diffstat);
+	}
+}
+
 void diff_addremove(struct diff_options *options,
 		    int addremove, unsigned mode,
 		    const struct object_id *oid,
@@ -6700,8 +6794,11 @@ void diff_change(struct diff_options *options,
 		return;
 
 	if (options->flags.quick && options->skip_stat_unmatch &&
-	    !diff_filespec_check_stat_unmatch(options->repo, p))
+	    !diff_filespec_check_stat_unmatch(options->repo, p)) {
+		diff_free_filespec_data(p->one);
+		diff_free_filespec_data(p->two);
 		return;
+	}
 
 	options->flags.has_changes = 1;
 }
@@ -6773,7 +6870,7 @@ size_t fill_textconv(struct repository *r,
 			*outbuf = "";
 			return 0;
 		}
-		if (diff_populate_filespec(r, df, 0))
+		if (diff_populate_filespec(r, df, NULL))
 			die("unable to read files to diff");
 		*outbuf = df->data;
 		return df->size;