1 files changed, 151 insertions, 81 deletions

diff --git a/builtin/blame.c b/builtin/blame.c
index 048ed53c2f..1e214bd4ec 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -6,6 +6,7 @@
  */
 
 #include "cache.h"
+#include "refs.h"
 #include "builtin.h"
 #include "blob.h"
 #include "commit.h"
@@ -27,6 +28,7 @@
 #include "line-range.h"
 #include "line-log.h"
 #include "dir.h"
+#include "progress.h"
 
 static char blame_usage[] = N_("git blame [<options>] [<rev-opts>] [<rev>] [--] <file>");
 
@@ -49,11 +51,12 @@ static int incremental;
 static int xdl_opts;
 static int abbrev = -1;
 static int no_whole_file_rename;
+static int show_progress;
 
-static enum date_mode blame_date_mode = DATE_ISO8601;
+static struct date_mode blame_date_mode = { DATE_ISO8601 };
 static size_t blame_date_width;
 
-static struct string_list mailmap;
+static struct string_list mailmap = STRING_LIST_INIT_NODUP;
 
 #ifndef DEBUG
 #define DEBUG 0
@@ -126,6 +129,11 @@ struct origin {
 	char path[FLEX_ARRAY];
 };
 
+struct progress_info {
+	struct progress *progress;
+	int blamed_lines;
+};
+
 static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b, long ctxlen,
 		      xdl_emit_hunk_consume_func_t hunk_func, void *cb_data)
 {
@@ -458,12 +466,11 @@ static void queue_blames(struct scoreboard *sb, struct origin *porigin,
 static struct origin *make_origin(struct commit *commit, const char *path)
 {
 	struct origin *o;
-	o = xcalloc(1, sizeof(*o) + strlen(path) + 1);
+	FLEX_ALLOC_STR(o, path, path);
 	o->commit = commit;
 	o->refcnt = 1;
 	o->next = commit->util;
 	commit->util = o;
-	strcpy(o->path, path);
 	return o;
 }
 
@@ -504,7 +511,7 @@ static int fill_blob_sha1_and_mode(struct origin *origin)
 {
 	if (!is_null_sha1(origin->blob_sha1))
 		return 0;
-	if (get_tree_entry(origin->commit->object.sha1,
+	if (get_tree_entry(origin->commit->object.oid.hash,
 			   origin->path,
 			   origin->blob_sha1, &origin->mode))
 		goto error_out;
@@ -555,11 +562,11 @@ static struct origin *find_origin(struct scoreboard *sb,
 		       PATHSPEC_LITERAL_PATH, "", paths);
 	diff_setup_done(&diff_opts);
 
-	if (is_null_sha1(origin->commit->object.sha1))
-		do_diff_cache(parent->tree->object.sha1, &diff_opts);
+	if (is_null_oid(&origin->commit->object.oid))
+		do_diff_cache(parent->tree->object.oid.hash, &diff_opts);
 	else
-		diff_tree_sha1(parent->tree->object.sha1,
-			       origin->commit->tree->object.sha1,
+		diff_tree_sha1(parent->tree->object.oid.hash,
+			       origin->commit->tree->object.oid.hash,
 			       "", &diff_opts);
 	diffcore_std(&diff_opts);
 
@@ -602,7 +609,7 @@ static struct origin *find_origin(struct scoreboard *sb,
 		}
 	}
 	diff_flush(&diff_opts);
-	free_pathspec(&diff_opts.pathspec);
+	clear_pathspec(&diff_opts.pathspec);
 	return porigin;
 }
 
@@ -625,11 +632,11 @@ static struct origin *find_rename(struct scoreboard *sb,
 	diff_opts.single_follow = origin->path;
 	diff_setup_done(&diff_opts);
 
-	if (is_null_sha1(origin->commit->object.sha1))
-		do_diff_cache(parent->tree->object.sha1, &diff_opts);
+	if (is_null_oid(&origin->commit->object.oid))
+		do_diff_cache(parent->tree->object.oid.hash, &diff_opts);
 	else
-		diff_tree_sha1(parent->tree->object.sha1,
-			       origin->commit->tree->object.sha1,
+		diff_tree_sha1(parent->tree->object.oid.hash,
+			       origin->commit->tree->object.oid.hash,
 			       "", &diff_opts);
 	diffcore_std(&diff_opts);
 
@@ -644,7 +651,7 @@ static struct origin *find_rename(struct scoreboard *sb,
 		}
 	}
 	diff_flush(&diff_opts);
-	free_pathspec(&diff_opts.pathspec);
+	clear_pathspec(&diff_opts.pathspec);
 	return porigin;
 }
 
@@ -975,8 +982,8 @@ static void pass_blame_to_parent(struct scoreboard *sb,
 
 	if (diff_hunks(&file_p, &file_o, 0, blame_chunk_cb, &d))
 		die("unable to generate diff (%s -> %s)",
-		    sha1_to_hex(parent->commit->object.sha1),
-		    sha1_to_hex(target->commit->object.sha1));
+		    oid_to_hex(&parent->commit->object.oid),
+		    oid_to_hex(&target->commit->object.oid));
 	/* The rest are the same as the parent */
 	blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
 	*d.dstq = NULL;
@@ -1124,7 +1131,7 @@ static void find_copy_in_blob(struct scoreboard *sb,
 	memset(split, 0, sizeof(struct blame_entry [3]));
 	if (diff_hunks(file_p, &file_o, 1, handle_split_cb, &d))
 		die("unable to generate diff (%s)",
-		    sha1_to_hex(parent->commit->object.sha1));
+		    oid_to_hex(&parent->commit->object.oid));
 	/* remainder, if any, all match the preimage */
 	handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
 }
@@ -1273,11 +1280,11 @@ static void find_copy_in_parent(struct scoreboard *sb,
 		&& (!porigin || strcmp(target->path, porigin->path))))
 		DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
 
-	if (is_null_sha1(target->commit->object.sha1))
-		do_diff_cache(parent->tree->object.sha1, &diff_opts);
+	if (is_null_oid(&target->commit->object.oid))
+		do_diff_cache(parent->tree->object.oid.hash, &diff_opts);
 	else
-		diff_tree_sha1(parent->tree->object.sha1,
-			       target->commit->tree->object.sha1,
+		diff_tree_sha1(parent->tree->object.oid.hash,
+			       target->commit->tree->object.oid.hash,
 			       "", &diff_opts);
 
 	if (!DIFF_OPT_TST(&diff_opts, FIND_COPIES_HARDER))
@@ -1336,7 +1343,7 @@ static void find_copy_in_parent(struct scoreboard *sb,
 	} while (unblamed);
 	target->suspects = reverse_blame(leftover, NULL);
 	diff_flush(&diff_opts);
-	free_pathspec(&diff_opts.pathspec);
+	clear_pathspec(&diff_opts.pathspec);
 }
 
 /*
@@ -1370,8 +1377,15 @@ static void pass_whole_blame(struct scoreboard *sb,
  */
 static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit)
 {
-	if (!reverse)
+	if (!reverse) {
+		if (revs->first_parent_only &&
+		    commit->parents &&
+		    commit->parents->next) {
+			free_commit_list(commit->parents->next);
+			commit->parents->next = NULL;
+		}
 		return commit->parents;
+	}
 	return lookup_decoration(&revs->children, &commit->object);
 }
 
@@ -1681,7 +1695,7 @@ static void get_commit_info(struct commit *commit,
 	if (len)
 		strbuf_add(&ret->summary, subject, len);
 	else
-		strbuf_addf(&ret->summary, "(%s)", sha1_to_hex(commit->object.sha1));
+		strbuf_addf(&ret->summary, "(%s)", oid_to_hex(&commit->object.oid));
 
 	unuse_commit_buffer(commit, message);
 }
@@ -1724,7 +1738,7 @@ static int emit_one_suspect_detail(struct origin *suspect, int repeat)
 		printf("boundary\n");
 	if (suspect->previous) {
 		struct origin *prev = suspect->previous;
-		printf("previous %s ", sha1_to_hex(prev->commit->object.sha1));
+		printf("previous %s ", oid_to_hex(&prev->commit->object.oid));
 		write_name_quoted(prev->path, stdout, '\n');
 	}
 
@@ -1737,18 +1751,21 @@ static int emit_one_suspect_detail(struct origin *suspect, int repeat)
  * The blame_entry is found to be guilty for the range.
  * Show it in incremental output.
  */
-static void found_guilty_entry(struct blame_entry *ent)
+static void found_guilty_entry(struct blame_entry *ent,
+			   struct progress_info *pi)
 {
 	if (incremental) {
 		struct origin *suspect = ent->suspect;
 
 		printf("%s %d %d %d\n",
-		       sha1_to_hex(suspect->commit->object.sha1),
+		       oid_to_hex(&suspect->commit->object.oid),
 		       ent->s_lno + 1, ent->lno + 1, ent->num_lines);
 		emit_one_suspect_detail(suspect, 0);
 		write_filename_info(suspect->path);
 		maybe_flush_or_die(stdout, "stdout");
 	}
+	pi->blamed_lines += ent->num_lines;
+	display_progress(pi->progress, pi->blamed_lines);
 }
 
 /*
@@ -1759,6 +1776,11 @@ static void assign_blame(struct scoreboard *sb, int opt)
 {
 	struct rev_info *revs = sb->revs;
 	struct commit *commit = prio_queue_get(&sb->commits);
+	struct progress_info pi = { NULL, 0 };
+
+	if (show_progress)
+		pi.progress = start_progress_delay(_("Blaming lines"),
+						   sb->num_lines, 50, 1);
 
 	while (commit) {
 		struct blame_entry *ent;
@@ -1800,7 +1822,7 @@ static void assign_blame(struct scoreboard *sb, int opt)
 			suspect->guilty = 1;
 			for (;;) {
 				struct blame_entry *next = ent->next;
-				found_guilty_entry(ent);
+				found_guilty_entry(ent, &pi);
 				if (next) {
 					ent = next;
 					continue;
@@ -1816,6 +1838,8 @@ static void assign_blame(struct scoreboard *sb, int opt)
 		if (DEBUG) /* sanity */
 			sanity_check_refcnt(sb);
 	}
+
+	stop_progress(&pi.progress);
 }
 
 static const char *format_time(unsigned long time, const char *tz_str,
@@ -1832,7 +1856,7 @@ static const char *format_time(unsigned long time, const char *tz_str,
 		size_t time_width;
 		int tz;
 		tz = atoi(tz_str);
-		time_str = show_date(time, tz, blame_date_mode);
+		time_str = show_date(time, tz, &blame_date_mode);
 		strbuf_addstr(&time_buf, time_str);
 		/*
 		 * Add space paddings to time_buf to display a fixed width
@@ -1871,9 +1895,9 @@ static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
 	int cnt;
 	const char *cp;
 	struct origin *suspect = ent->suspect;
-	char hex[41];
+	char hex[GIT_SHA1_HEXSZ + 1];
 
-	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
+	sha1_to_hex_r(hex, suspect->commit->object.oid.hash);
 	printf("%s %d %d %d\n",
 	       hex,
 	       ent->s_lno + 1,
@@ -1909,11 +1933,11 @@ static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
 	const char *cp;
 	struct origin *suspect = ent->suspect;
 	struct commit_info ci;
-	char hex[41];
+	char hex[GIT_SHA1_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
 
 	get_commit_info(suspect->commit, &ci, 1);
-	strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
+	sha1_to_hex_r(hex, suspect->commit->object.oid.hash);
 
 	cp = nth_line(sb, ent->lno);
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
@@ -2033,7 +2057,8 @@ static int prepare_lines(struct scoreboard *sb)
 	for (p = buf; p < end; p = get_next_line(p, end))
 		num++;
 
-	sb->lineno = lineno = xmalloc(sizeof(*sb->lineno) * (num + 1));
+	ALLOC_ARRAY(sb->lineno, num + 1);
+	lineno = sb->lineno;
 
 	for (p = buf; p < end; p = get_next_line(p, end))
 		*lineno++ = p - buf;
@@ -2068,7 +2093,7 @@ static int read_ancestry(const char *graft_file)
 
 static int update_auto_abbrev(int auto_abbrev, struct origin *suspect)
 {
-	const char *uniq = find_unique_abbrev(suspect->commit->object.sha1,
+	const char *uniq = find_unique_abbrev(suspect->commit->object.oid.hash,
 					      auto_abbrev);
 	int len = strlen(uniq);
 	if (auto_abbrev < len)
@@ -2144,7 +2169,7 @@ static void sanity_check_refcnt(struct scoreboard *sb)
 		if (ent->suspect->refcnt <= 0) {
 			fprintf(stderr, "%s in %s has negative refcnt %d\n",
 				ent->suspect->path,
-				sha1_to_hex(ent->suspect->commit->object.sha1),
+				oid_to_hex(&ent->suspect->commit->object.oid),
 				ent->suspect->refcnt);
 			baa = 1;
 		}
@@ -2181,10 +2206,18 @@ static int git_blame_config(const char *var, const char *value, void *cb)
 		blank_boundary = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "blame.showemail")) {
+		int *output_option = cb;
+		if (git_config_bool(var, value))
+			*output_option |= OUTPUT_SHOW_EMAIL;
+		else
+			*output_option &= ~OUTPUT_SHOW_EMAIL;
+		return 0;
+	}
 	if (!strcmp(var, "blame.date")) {
 		if (!value)
 			return config_error_nonbool(var);
-		blame_date_mode = parse_date_format(value);
+		parse_date_format(value, &blame_date_mode);
 		return 0;
 	}
 
@@ -2199,7 +2232,7 @@ static void verify_working_tree_path(struct commit *work_tree, const char *path)
 	struct commit_list *parents;
 
 	for (parents = work_tree->parents; parents; parents = parents->next) {
-		const unsigned char *commit_sha1 = parents->item->object.sha1;
+		const unsigned char *commit_sha1 = parents->item->object.oid.hash;
 		unsigned char blob_sha1[20];
 		unsigned mode;
 
@@ -2223,20 +2256,19 @@ static struct commit_list **append_parent(struct commit_list **tail, const unsig
 static void append_merge_parents(struct commit_list **tail)
 {
 	int merge_head;
-	const char *merge_head_file = git_path("MERGE_HEAD");
 	struct strbuf line = STRBUF_INIT;
 
-	merge_head = open(merge_head_file, O_RDONLY);
+	merge_head = open(git_path_merge_head(), O_RDONLY);
 	if (merge_head < 0) {
 		if (errno == ENOENT)
 			return;
-		die("cannot open '%s' for reading", merge_head_file);
+		die("cannot open '%s' for reading", git_path_merge_head());
 	}
 
 	while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
 		unsigned char sha1[20];
 		if (line.len < 40 || get_sha1_hex(line.buf, sha1))
-			die("unknown line in '%s': %s", merge_head_file, line.buf);
+			die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
 		tail = append_parent(tail, sha1);
 	}
 	close(merge_head);
@@ -2275,6 +2307,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	unsigned mode;
 	struct strbuf msg = STRBUF_INIT;
 
+	read_cache();
 	time(&now);
 	commit = alloc_commit_node();
 	commit->object.parsed = 1;
@@ -2294,7 +2327,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
 	for (parent = commit->parents; parent; parent = parent->next)
 		strbuf_addf(&msg, "parent %s\n",
-			    sha1_to_hex(parent->item->object.sha1));
+			    oid_to_hex(&parent->item->object.oid));
 	strbuf_addf(&msg,
 		    "author %s\n"
 		    "committer %s\n\n"
@@ -2376,42 +2409,41 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	ce->ce_mode = create_ce_mode(mode);
 	add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
 
-	/*
-	 * We are not going to write this out, so this does not matter
-	 * right now, but someday we might optimize diff-index --cached
-	 * with cache-tree information.
-	 */
 	cache_tree_invalidate_path(&the_index, path);
 
 	return commit;
 }
 
-static char *prepare_final(struct scoreboard *sb)
+static struct commit *find_single_final(struct rev_info *revs,
+					const char **name_p)
 {
 	int i;
-	const char *final_commit_name = NULL;
-	struct rev_info *revs = sb->revs;
+	struct commit *found = NULL;
+	const char *name = NULL;
 
-	/*
-	 * There must be one and only one positive commit in the
-	 * revs->pending array.
-	 */
 	for (i = 0; i < revs->pending.nr; i++) {
 		struct object *obj = revs->pending.objects[i].item;
 		if (obj->flags & UNINTERESTING)
 			continue;
-		while (obj->type == OBJ_TAG)
-			obj = deref_tag(obj, NULL, 0);
+		obj = deref_tag(obj, NULL, 0);
 		if (obj->type != OBJ_COMMIT)
 			die("Non commit %s?", revs->pending.objects[i].name);
-		if (sb->final)
+		if (found)
 			die("More than one commit to dig from %s and %s?",
-			    revs->pending.objects[i].name,
-			    final_commit_name);
-		sb->final = (struct commit *) obj;
-		final_commit_name = revs->pending.objects[i].name;
+			    revs->pending.objects[i].name, name);
+		found = (struct commit *)obj;
+		name = revs->pending.objects[i].name;
 	}
-	return xstrdup_or_null(final_commit_name);
+	if (name_p)
+		*name_p = name;
+	return found;
+}
+
+static char *prepare_final(struct scoreboard *sb)
+{
+	const char *name;
+	sb->final = find_single_final(sb->revs, &name);
+	return xstrdup_or_null(name);
 }
 
 static char *prepare_initial(struct scoreboard *sb)
@@ -2428,8 +2460,7 @@ static char *prepare_initial(struct scoreboard *sb)
 		struct object *obj = revs->pending.objects[i].item;
 		if (!(obj->flags & UNINTERESTING))
 			continue;
-		while (obj->type == OBJ_TAG)
-			obj = deref_tag(obj, NULL, 0);
+		obj = deref_tag(obj, NULL, 0);
 		if (obj->type != OBJ_COMMIT)
 			die("Non commit %s?", revs->pending.objects[i].name);
 		if (sb->final)
@@ -2487,17 +2518,19 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 	long dashdash_pos, lno;
 	char *final_commit_name = NULL;
 	enum object_type type;
-
-	static struct string_list range_list;
-	static int output_option = 0, opt = 0;
-	static int show_stats = 0;
-	static const char *revs_file = NULL;
-	static const char *contents_from = NULL;
-	static const struct option options[] = {
+	struct commit *final_commit = NULL;
+
+	struct string_list range_list = STRING_LIST_INIT_NODUP;
+	int output_option = 0, opt = 0;
+	int show_stats = 0;
+	const char *revs_file = NULL;
+	const char *contents_from = NULL;
+	const struct option options[] = {
 		OPT_BOOL(0, "incremental", &incremental, N_("Show blame entries as we find them, incrementally")),
 		OPT_BOOL('b', NULL, &blank_boundary, N_("Show blank SHA-1 for boundary commits (Default: off)")),
 		OPT_BOOL(0, "root", &show_root, N_("Do not treat root commits as boundaries (Default: off)")),
 		OPT_BOOL(0, "show-stats", &show_stats, N_("Show work cost statistics")),
+		OPT_BOOL(0, "progress", &show_progress, N_("Force progress reporting")),
 		OPT_BIT(0, "score-debug", &output_option, N_("Show output score for blame entries"), OUTPUT_SHOW_SCORE),
 		OPT_BIT('f', "show-name", &output_option, N_("Show original filename (Default: auto)"), OUTPUT_SHOW_NAME),
 		OPT_BIT('n', "show-number", &output_option, N_("Show original linenumber (Default: off)"), OUTPUT_SHOW_NUMBER),
@@ -2525,7 +2558,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 	unsigned int range_i;
 	long anchor;
 
-	git_config(git_blame_config, NULL);
+	git_config(git_blame_config, &output_option);
 	init_revisions(&revs, NULL);
 	revs.date_mode = blame_date_mode;
 	DIFF_OPT_SET(&revs.diffopt, ALLOW_TEXTCONV);
@@ -2533,6 +2566,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 
 	save_commit_buffer = 0;
 	dashdash_pos = 0;
+	show_progress = -1;
 
 	parse_options_start(&ctx, argc, argv, prefix, options,
 			    PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0);
@@ -2557,6 +2591,13 @@ parse_done:
 	DIFF_OPT_CLR(&revs.diffopt, FOLLOW_RENAMES);
 	argc = parse_options_end(&ctx);
 
+	if (incremental || (output_option & OUTPUT_PORCELAIN)) {
+		if (show_progress > 0)
+			die("--progress can't be used with --incremental or porcelain formats");
+		show_progress = 0;
+	} else if (show_progress < 0)
+		show_progress = isatty(2);
+
 	if (0 < abbrev)
 		/* one more abbrev length is needed for the boundary commit */
 		abbrev++;
@@ -2566,13 +2607,13 @@ parse_done:
 
 	if (cmd_is_annotate) {
 		output_option |= OUTPUT_ANNOTATE_COMPAT;
-		blame_date_mode = DATE_ISO8601;
+		blame_date_mode.type = DATE_ISO8601;
 	} else {
 		blame_date_mode = revs.date_mode;
 	}
 
 	/* The maximum width used to show the dates */
-	switch (blame_date_mode) {
+	switch (blame_date_mode.type) {
 	case DATE_RFC2822:
 		blame_date_width = sizeof("Thu, 19 Oct 2006 16:00:04 -0700");
 		break;
@@ -2597,10 +2638,12 @@ parse_done:
 		   fewer display columns. */
 		blame_date_width = utf8_strwidth(_("4 years, 11 months ago")) + 1; /* add the null */
 		break;
-	case DATE_LOCAL:
 	case DATE_NORMAL:
 		blame_date_width = sizeof("Thu Oct 19 16:00:04 2006 -0700");
 		break;
+	case DATE_STRFTIME:
+		blame_date_width = strlen(show_date(0, 0, &blame_date_mode)) + 1; /* add the null */
+		break;
 	}
 	blame_date_width -= 1; /* strip the null */
 
@@ -2673,10 +2716,12 @@ parse_done:
 		sb.commits.compare = compare_commits_by_commit_date;
 	}
 	else if (contents_from)
-		die("--contents and --children do not blend well.");
+		die("--contents and --reverse do not blend well.");
 	else {
 		final_commit_name = prepare_initial(&sb);
 		sb.commits.compare = compare_commits_by_reverse_commit_date;
+		if (revs.first_parent_only)
+			revs.children.name = NULL;
 	}
 
 	if (!sb.final) {
@@ -2693,6 +2738,12 @@ parse_done:
 	else if (contents_from)
 		die("Cannot use --contents with final commit object name");
 
+	if (reverse && revs.first_parent_only) {
+		final_commit = find_single_final(sb.revs, NULL);
+		if (!final_commit)
+			die("--reverse and --first-parent together require specified latest commit");
+	}
+
 	/*
 	 * If we have bottom, this will mark the ancestors of the
 	 * bottom commits we would reach while traversing as
@@ -2701,7 +2752,26 @@ parse_done:
 	if (prepare_revision_walk(&revs))
 		die(_("revision walk setup failed"));
 
-	if (is_null_sha1(sb.final->object.sha1)) {
+	if (reverse && revs.first_parent_only) {
+		struct commit *c = final_commit;
+
+		sb.revs->children.name = "children";
+		while (c->parents &&
+		       oidcmp(&c->object.oid, &sb.final->object.oid)) {
+			struct commit_list *l = xcalloc(1, sizeof(*l));
+
+			l->item = c;
+			if (add_decoration(&sb.revs->children,
+					   &c->parents->item->object, l))
+				die("BUG: not unique item in first-parent chain");
+			c = c->parents->item;
+		}
+
+		if (oidcmp(&c->object.oid, &sb.final->object.oid))
+			die("--reverse --first-parent together require range along first-parent chain");
+	}
+
+	if (is_null_oid(&sb.final->object.oid)) {
 		o = sb.final->util;
 		sb.final_buf = xmemdupz(o->file.ptr, o->file.size);
 		sb.final_buf_size = o->file.size;
@@ -2777,11 +2847,11 @@ parse_done:
 
 	read_mailmap(&mailmap, NULL);
 
+	assign_blame(&sb, opt);
+
 	if (!incremental)
 		setup_pager();
 
-	assign_blame(&sb, opt);
-
 	free(final_commit_name);
 
 	if (incremental)