diff --git a/builtin/commit.c b/builtin/commit.c
index 41f481bd03..4a45bedc09 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -545,77 +545,80 @@ static int sane_ident_split(struct ident_split *person)
 	return 1;
 }
 
-static int parse_force_date(const char *in, char *out, int len)
+static int parse_force_date(const char *in, struct strbuf *out)
 {
-	if (len < 1)
-		return -1;
-	*out++ = '@';
-	len--;
+	strbuf_addch(out, '@');
 
-	if (parse_date(in, out, len) < 0) {
+	if (parse_date(in, out) < 0) {
 		int errors = 0;
 		unsigned long t = approxidate_careful(in, &errors);
 		if (errors)
 			return -1;
-		snprintf(out, len, "%lu", t);
+		strbuf_addf(out, "%lu", t);
 	}
 
 	return 0;
 }
 
+static void set_ident_var(char **buf, char *val)
+{
+	free(*buf);
+	*buf = val;
+}
+
+static char *envdup(const char *var)
+{
+	const char *val = getenv(var);
+	return val ? xstrdup(val) : NULL;
+}
+
 static void determine_author_info(struct strbuf *author_ident)
 {
 	char *name, *email, *date;
 	struct ident_split author;
-	char date_buf[64];
 
-	name = getenv("GIT_AUTHOR_NAME");
-	email = getenv("GIT_AUTHOR_EMAIL");
-	date = getenv("GIT_AUTHOR_DATE");
+	name = envdup("GIT_AUTHOR_NAME");
+	email = envdup("GIT_AUTHOR_EMAIL");
+	date = envdup("GIT_AUTHOR_DATE");
 
 	if (author_message) {
-		const char *a, *lb, *rb, *eol;
+		struct ident_split ident;
 		size_t len;
+		const char *a;
 
-		a = strstr(author_message_buffer, "\nauthor ");
+		a = find_commit_header(author_message_buffer, "author", &len);
 		if (!a)
-			die(_("invalid commit: %s"), author_message);
+			die(_("commit '%s' lacks author header"), author_message);
+		if (split_ident_line(&ident, a, len) < 0)
+			die(_("commit '%s' has malformed author line"), author_message);
 
-		lb = strchrnul(a + strlen("\nauthor "), '<');
-		rb = strchrnul(lb, '>');
-		eol = strchrnul(rb, '\n');
-		if (!*lb || !*rb || !*eol)
-			die(_("invalid commit: %s"), author_message);
+		set_ident_var(&name, xmemdupz(ident.name_begin, ident.name_end - ident.name_begin));
+		set_ident_var(&email, xmemdupz(ident.mail_begin, ident.mail_end - ident.mail_begin));
 
-		if (lb == a + strlen("\nauthor "))
-			/* \nauthor <foo@example.com> */
-			name = xcalloc(1, 1);
-		else
-			name = xmemdupz(a + strlen("\nauthor "),
-					(lb - strlen(" ") -
-					 (a + strlen("\nauthor "))));
-		email = xmemdupz(lb + strlen("<"), rb - (lb + strlen("<")));
-		len = eol - (rb + strlen("> "));
-		date = xmalloc(len + 2);
-		*date = '@';
-		memcpy(date + 1, rb + strlen("> "), len);
-		date[len + 1] = '\0';
+		if (ident.date_begin) {
+			struct strbuf date_buf = STRBUF_INIT;
+			strbuf_addch(&date_buf, '@');
+			strbuf_add(&date_buf, ident.date_begin, ident.date_end - ident.date_begin);
+			strbuf_addch(&date_buf, ' ');
+			strbuf_add(&date_buf, ident.tz_begin, ident.tz_end - ident.tz_begin);
+			set_ident_var(&date, strbuf_detach(&date_buf, NULL));
+		}
 	}
 
 	if (force_author) {
-		const char *lb = strstr(force_author, " <");
-		const char *rb = strchr(force_author, '>');
+		struct ident_split ident;
 
-		if (!lb || !rb)
+		if (split_ident_line(&ident, force_author, strlen(force_author)) < 0)
 			die(_("malformed --author parameter"));
-		name = xstrndup(force_author, lb - force_author);
-		email = xstrndup(lb + 2, rb - (lb + 2));
+		set_ident_var(&name, xmemdupz(ident.name_begin, ident.name_end - ident.name_begin));
+		set_ident_var(&email, xmemdupz(ident.mail_begin, ident.mail_end - ident.mail_begin));
 	}
 
 	if (force_date) {
-		if (parse_force_date(force_date, date_buf, sizeof(date_buf)))
+		struct strbuf date_buf = STRBUF_INIT;
+		if (parse_force_date(force_date, &date_buf))
 			die(_("invalid date format: %s"), force_date);
-		date = date_buf;
+		set_ident_var(&date, strbuf_detach(&date_buf, NULL));
 	}
 
 	strbuf_addstr(author_ident, fmt_ident(name, email, date, IDENT_STRICT));
@@ -625,6 +628,10 @@ static void determine_author_info(struct strbuf *author_ident)
 		export_one("GIT_AUTHOR_EMAIL", author.mail_begin, author.mail_end, 0);
 		export_one("GIT_AUTHOR_DATE", author.date_begin, author.tz_end, '@');
 	}
+
+	free(name);
+	free(email);
+	free(date);
 }
 
 static void split_ident_or_die(struct ident_split *id, const struct strbuf *buf)
diff --git a/cache.h b/cache.h
index 823feb87b7..db4ccd1cf7 100644
--- a/cache.h
+++ b/cache.h
@@ -1047,10 +1047,10 @@ enum date_mode {
 const char *show_date(unsigned long time, int timezone, enum date_mode mode);
 void show_date_relative(unsigned long time, int tz, const struct timeval *now,
 			struct strbuf *timebuf);
-int parse_date(const char *date, char *buf, int bufsize);
+int parse_date(const char *date, struct strbuf *out);
 int parse_date_basic(const char *date, unsigned long *timestamp, int *offset);
 int parse_expiry_date(const char *date, unsigned long *timestamp);
-void datestamp(char *buf, int bufsize);
+void datestamp(struct strbuf *out);
 #define approxidate(s) approxidate_careful((s), NULL)
 unsigned long approxidate_careful(const char *, int *);
 unsigned long approxidate_relative(const char *date, const struct timeval *now);
diff --git a/commit.c b/commit.c
index ae7f2b10f4..9416d842c6 100644
--- a/commit.c
+++ b/commit.c
@@ -584,25 +584,19 @@ define_commit_slab(author_date_slab, unsigned long);
 static void record_author_date(struct author_date_slab *author_date,
 			       struct commit *commit)
 {
-	const char *buf, *line_end, *ident_line;
 	const char *buffer = get_commit_buffer(commit, NULL);
 	struct ident_split ident;
+	const char *ident_line;
+	size_t ident_len;
 	char *date_end;
 	unsigned long date;
 
-	for (buf = buffer; buf; buf = line_end + 1) {
-		line_end = strchrnul(buf, '\n');
-		if (!skip_prefix(buf, "author ", &ident_line)) {
-			if (!line_end[0] || line_end[1] == '\n')
-				return; /* end of header */
-			continue;
-		}
-		if (split_ident_line(&ident,
-				     ident_line, line_end - ident_line) ||
-		    !ident.date_begin || !ident.date_end)
-			goto fail_exit; /* malformed "author" line */
-		break;
-	}
+	ident_line = find_commit_header(buffer, "author", &ident_len);
+	if (!ident_line)
+		goto fail_exit; /* no author line */
+	if (split_ident_line(&ident, ident_line, ident_len) ||
+	    !ident.date_begin || !ident.date_end)
+		goto fail_exit; /* malformed "author" line */
 
 	date = strtoul(ident.date_begin, &date_end, 10);
 	if (date_end != ident.date_end)
@@ -1660,3 +1654,25 @@ void print_commit_list(struct commit_list *list,
 		printf(format, sha1_to_hex(list->item->object.sha1));
 	}
 }
+
+const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
+{
+	int key_len = strlen(key);
+	const char *line = msg;
+
+	while (line) {
+		const char *eol = strchrnul(line, '\n');
+
+		if (line == eol)
+			return NULL;
+
+		if (eol - line > key_len &&
+		    !strncmp(line, key, key_len) &&
+		    line[key_len] == ' ') {
+			*out_len = eol - line - key_len - 1;
+			return line + key_len + 1;
+		}
+		line = *eol ? eol + 1 : NULL;
+	}
+	return NULL;
+}
diff --git a/commit.h b/commit.h
index a401ddfbc4..470c74569f 100644
--- a/commit.h
+++ b/commit.h
@@ -326,6 +326,17 @@ extern struct commit_extra_header *read_commit_extra_headers(struct commit *, co
 
 extern void free_commit_extra_headers(struct commit_extra_header *extra);
 
+/*
+ * Search the commit object contents given by "msg" for the header "key".
+ * Returns a pointer to the start of the header contents, or NULL. The length
+ * of the header, up to the first newline, is returned via out_len.
+ *
+ * Note that some headers (like mergetag) may be multi-line. It is the caller's
+ * responsibility to parse further in this case!
+ */
+extern const char *find_commit_header(const char *msg, const char *key,
+				      size_t *out_len);
+
 typedef void (*each_mergetag_fn)(struct commit *commit, struct commit_extra_header *extra,
 				 void *cb_data);
 
diff --git a/date.c b/date.c
index 5d73d9b7b2..59dfe579c6 100644
--- a/date.c
+++ b/date.c
@@ -614,7 +614,7 @@ static int match_tz(const char *date, int *offp)
 	return end - date;
 }
 
-static int date_string(unsigned long date, int offset, char *buf, int len)
+static void date_string(unsigned long date, int offset, struct strbuf *buf)
 {
 	int sign = '+';
 
@@ -622,7 +622,7 @@ static int date_string(unsigned long date, int offset, char *buf, int len)
 		offset = -offset;
 		sign = '-';
 	}
-	return snprintf(buf, len, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
+	strbuf_addf(buf, "%lu %c%02d%02d", date, sign, offset / 60, offset % 60);
 }
 
 /*
@@ -744,13 +744,14 @@ int parse_expiry_date(const char *date, unsigned long *timestamp)
 	return errors;
 }
 
-int parse_date(const char *date, char *result, int maxlen)
+int parse_date(const char *date, struct strbuf *result)
 {
 	unsigned long timestamp;
 	int offset;
 	if (parse_date_basic(date, &timestamp, &offset))
 		return -1;
-	return date_string(timestamp, offset, result, maxlen);
+	date_string(timestamp, offset, result);
+	return 0;
 }
 
 enum date_mode parse_date_format(const char *format)
@@ -778,7 +779,7 @@ enum date_mode parse_date_format(const char *format)
 		die("unknown date format %s", format);
 }
 
-void datestamp(char *buf, int bufsize)
+void datestamp(struct strbuf *out)
 {
 	time_t now;
 	int offset;
@@ -788,7 +789,7 @@ void datestamp(char *buf, int bufsize)
 	offset = tm_to_time_t(localtime(&now)) - now;
 	offset /= 60;
 
-	date_string(now, offset, buf, bufsize);
+	date_string(now, offset, out);
 }
 
 /*
diff --git a/fast-import.c b/fast-import.c
index c071253c90..9e6134d034 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1996,7 +1996,7 @@ static int parse_data(struct strbuf *sb, uintmax_t limit, uintmax_t *len_res)
 	return 1;
 }
 
-static int validate_raw_date(const char *src, char *result, int maxlen)
+static int validate_raw_date(const char *src, struct strbuf *result)
 {
 	const char *orig_src = src;
 	char *endp;
@@ -2014,11 +2014,10 @@ static int validate_raw_date(const char *src, char *result, int maxlen)
 		return -1;
 
 	num = strtoul(src + 1, &endp, 10);
-	if (errno || endp == src + 1 || *endp || (endp - orig_src) >= maxlen ||
-	    1400 < num)
+	if (errno || endp == src + 1 || *endp || 1400 < num)
 		return -1;
 
-	strcpy(result, orig_src);
+	strbuf_addstr(result, orig_src);
 	return 0;
 }
 
@@ -2026,7 +2025,7 @@ static char *parse_ident(const char *buf)
 {
 	const char *ltgt;
 	size_t name_len;
-	char *ident;
+	struct strbuf ident = STRBUF_INIT;
 
 	/* ensure there is a space delimiter even if there is no name */
 	if (*buf == '<')
@@ -2045,26 +2044,25 @@ static char *parse_ident(const char *buf)
 		die("Missing space after > in ident string: %s", buf);
 	ltgt++;
 	name_len = ltgt - buf;
-	ident = xmalloc(name_len + 24);
-	strncpy(ident, buf, name_len);
+	strbuf_add(&ident, buf, name_len);
 
 	switch (whenspec) {
 	case WHENSPEC_RAW:
-		if (validate_raw_date(ltgt, ident + name_len, 24) < 0)
+		if (validate_raw_date(ltgt, &ident) < 0)
 			die("Invalid raw date \"%s\" in ident: %s", ltgt, buf);
 		break;
 	case WHENSPEC_RFC2822:
-		if (parse_date(ltgt, ident + name_len, 24) < 0)
+		if (parse_date(ltgt, &ident) < 0)
 			die("Invalid rfc2822 date \"%s\" in ident: %s", ltgt, buf);
 		break;
 	case WHENSPEC_NOW:
 		if (strcmp("now", ltgt))
 			die("Date in ident must be 'now': %s", buf);
-		datestamp(ident + name_len, 24);
+		datestamp(&ident);
 		break;
 	}
 
-	return ident;
+	return strbuf_detach(&ident, NULL);
 }
 
 static void parse_and_store_blob(
diff --git a/ident.c b/ident.c
index 77bc882e59..5ff1aadaaa 100644
--- a/ident.c
+++ b/ident.c
@@ -9,7 +9,7 @@
 
 static struct strbuf git_default_name = STRBUF_INIT;
 static struct strbuf git_default_email = STRBUF_INIT;
-static char git_default_date[50];
+static struct strbuf git_default_date = STRBUF_INIT;
 
 #define IDENT_NAME_GIVEN 01
 #define IDENT_MAIL_GIVEN 02
@@ -129,9 +129,9 @@ const char *ident_default_email(void)
 
 static const char *ident_default_date(void)
 {
-	if (!git_default_date[0])
-		datestamp(git_default_date, sizeof(git_default_date));
-	return git_default_date;
+	if (!git_default_date.len)
+		datestamp(&git_default_date);
+	return git_default_date.buf;
 }
 
 static int crud(unsigned char c)
@@ -292,7 +292,6 @@ const char *fmt_ident(const char *name, const char *email,
 		      const char *date_str, int flag)
 {
 	static struct strbuf ident = STRBUF_INIT;
-	char date[50];
 	int strict = (flag & IDENT_STRICT);
 	int want_date = !(flag & IDENT_NO_DATE);
 	int want_name = !(flag & IDENT_NO_NAME);
@@ -320,15 +319,6 @@ const char *fmt_ident(const char *name, const char *email,
 		die("unable to auto-detect email address (got '%s')", email);
 	}
 
-	if (want_date) {
-		if (date_str && date_str[0]) {
-			if (parse_date(date_str, date, sizeof(date)) < 0)
-				die("invalid date format: %s", date_str);
-		}
-		else
-			strcpy(date, ident_default_date());
-	}
-
 	strbuf_reset(&ident);
 	if (want_name) {
 		strbuf_addstr_without_crud(&ident, name);
@@ -339,8 +329,14 @@ const char *fmt_ident(const char *name, const char *email,
 			strbuf_addch(&ident, '>');
 	if (want_date) {
 		strbuf_addch(&ident, ' ');
-		strbuf_addstr_without_crud(&ident, date);
+		if (date_str && date_str[0]) {
+			if (parse_date(date_str, &ident) < 0)
+				die("invalid date format: %s", date_str);
+		}
+		else
+			strbuf_addstr(&ident, ident_default_date());
 	}
+
 	return ident.buf;
 }
 
diff --git a/pretty.c b/pretty.c
index 5f012a6b8e..63e03b67e9 100644
--- a/pretty.c
+++ b/pretty.c
@@ -554,31 +554,11 @@ static void add_merge_info(const struct pretty_print_context *pp,
 	strbuf_addch(sb, '\n');
 }
 
-static char *get_header(const struct commit *commit, const char *msg,
-			const char *key)
+static char *get_header(const char *msg, const char *key)
 {
-	int key_len = strlen(key);
-	const char *line = msg;
-
-	while (line) {
-		const char *eol = strchrnul(line, '\n'), *next;
-
-		if (line == eol)
-			return NULL;
-		if (!*eol) {
-			warning("malformed commit (header is missing newline): %s",
-				sha1_to_hex(commit->object.sha1));
-			next = NULL;
-		} else
-			next = eol + 1;
-		if (eol - line > key_len &&
-		    !strncmp(line, key, key_len) &&
-		    line[key_len] == ' ') {
-			return xmemdupz(line + key_len + 1, eol - line - key_len - 1);
-		}
-		line = next;
-	}
-	return NULL;
+	size_t len;
+	const char *v = find_commit_header(msg, key, &len);
+	return v ? xmemdupz(v, len) : NULL;
 }
 
 static char *replace_encoding_header(char *buf, const char *encoding)
@@ -624,11 +604,10 @@ const char *logmsg_reencode(const struct commit *commit,
 
 	if (!output_encoding || !*output_encoding) {
 		if (commit_encoding)
-			*commit_encoding =
-				get_header(commit, msg, "encoding");
+			*commit_encoding = get_header(msg, "encoding");
 		return msg;
 	}
-	encoding = get_header(commit, msg, "encoding");
+	encoding = get_header(msg, "encoding");
 	if (commit_encoding)
 		*commit_encoding = encoding;
 	use_encoding = encoding ? encoding : utf8;
diff --git a/test-date.c b/test-date.c
index 10afaabbfa..94a6997a8f 100644
--- a/test-date.c
+++ b/test-date.c
@@ -19,19 +19,21 @@ static void show_dates(char **argv, struct timeval *now)
 
 static void parse_dates(char **argv, struct timeval *now)
 {
+	struct strbuf result = STRBUF_INIT;
+
 	for (; *argv; argv++) {
-		char result[100];
 		unsigned long t;
 		int tz;
 
-		result[0] = 0;
-		parse_date(*argv, result, sizeof(result));
-		if (sscanf(result, "%lu %d", &t, &tz) == 2)
+		strbuf_reset(&result);
+		parse_date(*argv, &result);
+		if (sscanf(result.buf, "%lu %d", &t, &tz) == 2)
 			printf("%s -> %s\n",
 			       *argv, show_date(t, tz, DATE_ISO8601));
 		else
 			printf("%s -> bad\n", *argv);
 	}
+	strbuf_release(&result);
 }
 
 static void parse_approxidate(char **argv, struct timeval *now)