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

["Lukas Sandström" <luksan@gmail.com>]

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>
---

Jeff King wrote:
> On Thu, Nov 19, 2009 at 09:51:36AM +0100, Lukas Sandström wrote:
> Thanks, it did end up being a pretty small change. Though I think we may
> be better off with _both_ patches. Your patch protects the message
> absolutely during rebasing, and my patch improves the heuristic when
> applying non-rebase patches.
> 

I looked a bit at using your extra safety check, but it would be a change
in behavior to only accept valid email adresses, and mailinfo
is riddled with corner cases. If this changed is made someone
will propably complain, saying that they rely on invalid dates in their
commit messages.

I don't know when to apply your stricter check whithout breaking any tests.

>> @@ -771,6 +772,8 @@ static int handle_commit_msg(struct strbuf *line)
>>  		return 0;
>>
>>  	if (still_looking) {
>> +		if (!use_inbody_headers)
>> +			still_looking = 0;
>>  		strbuf_ltrim(line);
>>  		if (!line->len)
>>  			return 0;
> 
> Hmm. But we still end up in this conditional for the very first line.
> Which I guess happens to work because the first line we feed is
> presumably the empty blank line (but I didn't check). Still, wouldn't it
> be more clear as:
> 
>   if (use_inbody_headers && still_looking) {
>      ...
> 
> in which case still_looking simply becomes irrelevant when the feature
> is disabled?

When rebasing the first line passed to handle_commit_msg will be the blank
line between the headers and commit message. This should be removed. I
rewrote this part to make it a bit more obvious.

> 
>> +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
>> +---
> 
> Since your feature is meant to prevent us looking at inbody headers no
> matter if they are valid-looking or not, wouldn't a better test be to
> actually have:
> 
>   From: Other Author <other@example.com>
> 
> Otherwise, you don't know if it is your feature blocking it, or my patch
> (if it gets applied on top).
> 

I kept the tests as is for now, since they show the problem
originally reported.

/Lukas


 builtin-mailinfo.c                   |   12 +++++++++++-
 git-am.sh                            |   13 ++++++++++---
 t/t5100-mailinfo.sh                  |    6 +++++-
 t/t5100/info0015                     |    5 +++++
 t/t5100/info0015--no-inbody-headers  |    5 +++++
 t/t5100/info0016                     |    5 +++++
 t/t5100/info0016--no-inbody-headers  |    5 +++++
 t/t5100/msg0015                      |    2 ++
 t/t5100/msg0015--no-inbody-headers   |    3 +++
 t/t5100/msg0016                      |    2 ++
 t/t5100/msg0016--no-inbody-headers   |    4 ++++
 t/t5100/patch0015                    |    8 ++++++++
 t/t5100/patch0015--no-inbody-headers |    8 ++++++++
 t/t5100/patch0016                    |    8 ++++++++
 t/t5100/patch0016--no-inbody-headers |    8 ++++++++
 t/t5100/sample.mbox                  |   33 +++++++++++++++++++++++++++++++++
 16 files changed, 122 insertions(+), 5 deletions(-)
 create mode 100644 t/t5100/info0015
 create mode 100644 t/t5100/info0015--no-inbody-headers
 create mode 100644 t/t5100/info0016
 create mode 100644 t/t5100/info0016--no-inbody-headers
 create mode 100644 t/t5100/msg0015
 create mode 100644 t/t5100/msg0015--no-inbody-headers
 create mode 100644 t/t5100/msg0016
 create mode 100644 t/t5100/msg0016--no-inbody-headers
 create mode 100644 t/t5100/patch0015
 create mode 100644 t/t5100/patch0015--no-inbody-headers
 create mode 100644 t/t5100/patch0016
 create mode 100644 t/t5100/patch0016--no-inbody-headers

diff --git a/builtin-mailinfo.c b/builtin-mailinfo.c
index c90cd31..3c4f075 100644
--- a/builtin-mailinfo.c
+++ b/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++;
diff --git a/git-am.sh b/git-am.sh
index c132f50..96869a2 100755
--- a/git-am.sh
+++ b/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

diff --git a/t/t5100-mailinfo.sh b/t/t5100-mailinfo.sh
index 0279d07..ebc36c1 100755
--- a/t/t5100-mailinfo.sh
+++ b/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
diff --git a/t/t5100/info0015 b/t/t5100/info0015
new file mode 100644
index 0000000..0114f10
--- /dev/null
+++ b/t/t5100/info0015
@@ -0,0 +1,5 @@
+Author:
+Email:
+Subject: check bogus body header (from)
+Date: Fri, 9 Jun 2006 00:44:16 -0700
+
diff --git a/t/t5100/info0015--no-inbody-headers b/t/t5100/info0015--no-inbody-headers
new file mode 100644
index 0000000..c4d8d77
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/info0016 b/t/t5100/info0016
new file mode 100644
index 0000000..38ccd0d
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/info0016--no-inbody-headers b/t/t5100/info0016--no-inbody-headers
new file mode 100644
index 0000000..f4857d4
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/msg0015 b/t/t5100/msg0015
new file mode 100644
index 0000000..9577238
--- /dev/null
+++ b/t/t5100/msg0015
@@ -0,0 +1,2 @@
+- a list
+  - of stuff
diff --git a/t/t5100/msg0015--no-inbody-headers b/t/t5100/msg0015--no-inbody-headers
new file mode 100644
index 0000000..be5115b
--- /dev/null
+++ b/t/t5100/msg0015--no-inbody-headers
@@ -0,0 +1,3 @@
+From: bogosity
+  - a list
+  - of stuff
diff --git a/t/t5100/msg0016 b/t/t5100/msg0016
new file mode 100644
index 0000000..0d9adad
--- /dev/null
+++ b/t/t5100/msg0016
@@ -0,0 +1,2 @@
+and some content
+
diff --git a/t/t5100/msg0016--no-inbody-headers b/t/t5100/msg0016--no-inbody-headers
new file mode 100644
index 0000000..1063f51
--- /dev/null
+++ b/t/t5100/msg0016--no-inbody-headers
@@ -0,0 +1,4 @@
+Date: bogus
+
+and some content
+
diff --git a/t/t5100/patch0015 b/t/t5100/patch0015
new file mode 100644
index 0000000..ad64848
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/patch0015--no-inbody-headers b/t/t5100/patch0015--no-inbody-headers
new file mode 100644
index 0000000..ad64848
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/patch0016 b/t/t5100/patch0016
new file mode 100644
index 0000000..ad64848
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/patch0016--no-inbody-headers b/t/t5100/patch0016--no-inbody-headers
new file mode 100644
index 0000000..ad64848
--- /dev/null
+++ b/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
+
diff --git a/t/t5100/sample.mbox b/t/t5100/sample.mbox
index 13fa4ae..de10312 100644
--- a/t/t5100/sample.mbox
+++ b/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
+
-- 
1.6.4.4