Merge branch 'jk/mbox-from-line' into maint

Some MUAs mangled a line in a message that begins with "From " to
">From " when writing to a mailbox file and feeding such an input to
"git am" used to lose such a line.

* jk/mbox-from-line:
  mailinfo: work around -Wstring-plus-int warning
  mailinfo: make ">From" in-body header check more robust

builtin/mailinfo.c

@@ -288,6 +288,22 @@ static inline int cmp_header(const struct strbuf *line, const char *hdr)
 			line->buf[len] == ':' && isspace(line->buf[len + 1]);
 }
 
+static int is_format_patch_separator(const char *line, int len)
+{
+	static const char SAMPLE[] =
+		"From e6807f3efca28b30decfecb1732a56c7db1137ee Mon Sep 17 00:00:00 2001\n";
+	const char *cp;
+
+	if (len != strlen(SAMPLE))
+		return 0;
+	if (!skip_prefix(line, "From ", &cp))
+		return 0;
+	if (strspn(cp, "0123456789abcdef") != 40)
+		return 0;
+	cp += 40;
+	return !memcmp(SAMPLE + (cp - line), cp, strlen(SAMPLE) - (cp - line));
+}
+
 static int check_header(const struct strbuf *line,
 				struct strbuf *hdr_data[], int overwrite)
 {
@@ -329,7 +345,7 @@ static int check_header(const struct strbuf *line,
 
 	/* for inbody stuff */
 	if (starts_with(line->buf, ">From") && isspace(line->buf[5])) {
-		ret = 1; /* Should this return 0? */
+		ret = is_format_patch_separator(line->buf + 1, line->len - 1);
 		goto check_header_out;
 	}
 	if (starts_with(line->buf, "[PATCH]") && isspace(line->buf[7])) {

t/t5100-mailinfo.sh

@@ -89,4 +89,22 @@ test_expect_success 'mailinfo on from header without name works' '
 
 '
 
+test_expect_success 'mailinfo finds headers after embedded From line' '
+	mkdir embed-from &&
+	git mailsplit -oembed-from "$TEST_DIRECTORY"/t5100/embed-from.in &&
+	test_cmp "$TEST_DIRECTORY"/t5100/embed-from.in embed-from/0001 &&
+	git mailinfo embed-from/msg embed-from/patch \
+	  <embed-from/0001 >embed-from/out &&
+	test_cmp "$TEST_DIRECTORY"/t5100/embed-from.expect embed-from/out
+'
+
+test_expect_success 'mailinfo on message with quoted >From' '
+	mkdir quoted-from &&
+	git mailsplit -oquoted-from "$TEST_DIRECTORY"/t5100/quoted-from.in &&
+	test_cmp "$TEST_DIRECTORY"/t5100/quoted-from.in quoted-from/0001 &&
+	git mailinfo quoted-from/msg quoted-from/patch \
+	  <quoted-from/0001 >quoted-from/out &&
+	test_cmp "$TEST_DIRECTORY"/t5100/quoted-from.expect quoted-from/msg
+'
+
 test_done

t/t5100/embed-from.expect

@@ -0,0 +1,5 @@
+Author: Commit Author
+Email: commit@example.com
+Subject: patch subject
+Date: Sat, 13 Sep 2014 21:13:23 -0400 
+

t/t5100/embed-from.in

@@ -0,0 +1,13 @@
+From 1234567890123456789012345678901234567890 Mon Sep 17 00:00:00 2001
+From: Email Author <email@example.com>
+Date: Sun, 25 May 2008 00:38:18 -0700
+Subject: [PATCH] email subject
+
+>From 1234567890123456789012345678901234567890 Mon Sep 17 00:00:00 2001
+From: Commit Author <commit@example.com>
+Date: Sat, 13 Sep 2014 21:13:23 -0400
+Subject: patch subject
+
+patch body
+---
+patch

t/t5100/quoted-from.expect

@@ -0,0 +1,3 @@
+>From the depths of history, we are stuck with the
+flaky mbox format.
+

t/t5100/quoted-from.in

@@ -0,0 +1,10 @@
+From 1234567890123456789012345678901234567890 Mon Sep 17 00:00:00 2001
+From: Author Name <somebody@example.com>
+Date: Sun, 25 May 2008 00:38:18 -0700
+Subject: [PATCH] testing quoted >From
+
+>From the depths of history, we are stuck with the
+flaky mbox format.
+
+---
+patch