git am/mailinfo: Don't look at in-body headers when rebasing

When we are rebasing we know that the header lines in the
patch are good and that we don't need to pick up any headers
from the body of the patch.

This makes it possible to rebase commits whose commit message
start with "From" or "Date".

Test vectors by Jeff King.

Signed-off-by: Lukas Sandström <luksan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-mailinfo.c

@@ -26,6 +26,7 @@ static struct strbuf charset = STRBUF_INIT;
 static int patch_lines;
 static struct strbuf **p_hdr_data, **s_hdr_data;
 static int use_scissors;
+static int use_inbody_headers = 1;
 
 #define MAX_HDR_PARSED 10
 #define MAX_BOUNDARIES 5
@@ -774,10 +775,17 @@ static int handle_commit_msg(struct strbuf *line)
 		strbuf_ltrim(line);
 		if (!line->len)
 			return 0;
+	}
+
+	if (use_inbody_headers && still_looking) {
 		still_looking = check_header(line, s_hdr_data, 0);
 		if (still_looking)
 			return 0;
-	}
+	} else
+		/* Only trim the first (blank) line of the commit message
+		 * when ignoring in-body headers.
+		 */
+		still_looking = 0;
 
 	/* normalize the log message to UTF-8. */
 	if (metainfo_charset)
@@ -1033,6 +1041,8 @@ int cmd_mailinfo(int argc, const char **argv, const char *prefix)
 			use_scissors = 1;
 		else if (!strcmp(argv[1], "--no-scissors"))
 			use_scissors = 0;
+		else if (!strcmp(argv[1], "--no-inbody-headers"))
+			use_inbody_headers = 0;
 		else
 			usage(mailinfo_usage);
 		argc--; argv++;

git-am.sh

@@ -289,7 +289,7 @@ split_patches () {
 prec=4
 dotest="$GIT_DIR/rebase-apply"
 sign= utf8=t keep= skip= interactive= resolved= rebasing= abort=
-resolvemsg= resume= scissors=
+resolvemsg= resume= scissors= no_inbody_headers=
 git_apply_opt=
 committer_date_is_author_date=
 ignore_date=
@@ -322,7 +322,7 @@ do
 	--abort)
 		abort=t ;;
 	--rebasing)
-		rebasing=t threeway=t keep=t scissors=f ;;
+		rebasing=t threeway=t keep=t scissors=f no_inbody_headers=t ;;
 	-d|--dotest)
 		die "-d option is no longer supported.  Do not use."
 		;;
@@ -448,6 +448,7 @@ else
 	echo "$utf8" >"$dotest/utf8"
 	echo "$keep" >"$dotest/keep"
 	echo "$scissors" >"$dotest/scissors"
+	echo "$no_inbody_headers" >"$dotest/no_inbody_headers"
 	echo "$GIT_QUIET" >"$dotest/quiet"
 	echo 1 >"$dotest/next"
 	if test -n "$rebasing"
@@ -495,6 +496,12 @@ t)
 f)
 	scissors=--no-scissors ;;
 esac
+if test "$(cat "$dotest/no_inbody_headers")" = t
+then
+	no_inbody_headers=--no-inbody-headers
+else
+	no_inbody_headers=
+fi
 if test "$(cat "$dotest/quiet")" = t
 then
 	GIT_QUIET=t
@@ -549,7 +556,7 @@ do
 	# by the user, or the user can tell us to do so by --resolved flag.
 	case "$resume" in
 	'')
-		git mailinfo $keep $scissors $utf8 "$dotest/msg" "$dotest/patch" \
+		git mailinfo $keep $no_inbody_headers $scissors $utf8 "$dotest/msg" "$dotest/patch" \
 			<"$dotest/$msgnum" >"$dotest/info" ||
 			stop_here $this
 

t/t5100-mailinfo.sh

@@ -11,7 +11,7 @@ test_expect_success 'split sample box' \
 	'git mailsplit -o. "$TEST_DIRECTORY"/t5100/sample.mbox >last &&
 	last=`cat last` &&
 	echo total is $last &&
-	test `cat last` = 14'
+	test `cat last` = 16'
 
 check_mailinfo () {
 	mail=$1 opt=$2
@@ -30,6 +30,10 @@ do
 		if test -f "$TEST_DIRECTORY"/t5100/msg$mail--scissors
 		then
 			check_mailinfo $mail --scissors
+		fi &&
+		if test -f "$TEST_DIRECTORY"/t5100/msg$mail--no-inbody-headers
+		then
+			check_mailinfo $mail --no-inbody-headers
 		fi
 	'
 done

t/t5100/info0015

@@ -0,0 +1,5 @@
+Author: 
+Email: 
+Subject: check bogus body header (from)
+Date: Fri, 9 Jun 2006 00:44:16 -0700
+

t/t5100/info0015--no-inbody-headers

@@ -0,0 +1,5 @@
+Author: A U Thor
+Email: a.u.thor@example.com
+Subject: check bogus body header (from)
+Date: Fri, 9 Jun 2006 00:44:16 -0700
+

t/t5100/info0016

@@ -0,0 +1,5 @@
+Author: A U Thor
+Email: a.u.thor@example.com
+Subject: check bogus body header (date)
+Date: bogus 
+

t/t5100/info0016--no-inbody-headers

@@ -0,0 +1,5 @@
+Author: A U Thor
+Email: a.u.thor@example.com
+Subject: check bogus body header (date)
+Date: Fri, 9 Jun 2006 00:44:16 -0700
+

t/t5100/msg0015

@@ -0,0 +1,2 @@
+- a list
+  - of stuff

t/t5100/msg0015--no-inbody-headers

@@ -0,0 +1,3 @@
+From: bogosity
+  - a list
+  - of stuff

t/t5100/msg0016

@@ -0,0 +1,2 @@
+and some content
+

t/t5100/msg0016--no-inbody-headers

@@ -0,0 +1,4 @@
+Date: bogus
+
+and some content
+

t/t5100/patch0015

@@ -0,0 +1,8 @@
+---
+diff --git a/foo b/foo
+index e69de29..d95f3ad 100644
+--- a/foo
++++ b/foo
+@@ -0,0 +1 @@
++content
+

t/t5100/patch0015--no-inbody-headers

@@ -0,0 +1,8 @@
+---
+diff --git a/foo b/foo
+index e69de29..d95f3ad 100644
+--- a/foo
++++ b/foo
+@@ -0,0 +1 @@
++content
+

t/t5100/patch0016

@@ -0,0 +1,8 @@
+---
+diff --git a/foo b/foo
+index e69de29..d95f3ad 100644
+--- a/foo
++++ b/foo
+@@ -0,0 +1 @@
++content
+

t/t5100/patch0016--no-inbody-headers

@@ -0,0 +1,8 @@
+---
+diff --git a/foo b/foo
+index e69de29..d95f3ad 100644
+--- a/foo
++++ b/foo
+@@ -0,0 +1 @@
++content
+

t/t5100/sample.mbox

@@ -650,3 +650,36 @@ index b0b5d8f..461c47e 100644
  		convert_to_utf8(line, charset.buf);
 -- 
 1.6.4.1
+From nobody Mon Sep 17 00:00:00 2001
+From: A U Thor <a.u.thor@example.com>
+Subject: check bogus body header (from)
+Date: Fri, 9 Jun 2006 00:44:16 -0700
+
+From: bogosity
+  - a list
+  - of stuff
+---
+diff --git a/foo b/foo
+index e69de29..d95f3ad 100644
+--- a/foo
++++ b/foo
+@@ -0,0 +1 @@
++content
+
+From nobody Mon Sep 17 00:00:00 2001
+From: A U Thor <a.u.thor@example.com>
+Subject: check bogus body header (date)
+Date: Fri, 9 Jun 2006 00:44:16 -0700
+
+Date: bogus
+
+and some content
+
+---
+diff --git a/foo b/foo
+index e69de29..d95f3ad 100644
+--- a/foo
++++ b/foo
+@@ -0,0 +1 @@
++content
+