[PATCH] ref-filter: treat CRLF as same as LF in find_subpos

[DOAN Tran Cong Danh <congdanhqx@gmail.com>]

Starting from commit 949af06 (branch: use ref-filter printing APIs, 2017-01-10),
`git branch -v` doesn't treat CRLF as line separator anymore.

Quote from git mailing-list:

> Here is a recipe to reproduce the error:
>
>    git init
>    git commit --allow-empty -m initial
>    git branch crlf $(printf '%s\r\n' subject '' line3_long line4 |
>        git commit-tree HEAD:)
> The reason for the "bug" is obviously that a line having CR in addition
> to LF is not "an empty line". Consequently, the second line is not
> treated as a separator between subject and body, whereupon Git
> concatenates all line into one large subject line. This strips the LFs
> but leaves the CRS in tact, which, when printed on a terminal move the
> cursor to the beginning of the line, so that text after the CRs
> overwrites what is already in the terminal.

Reported-by: Animi Vulpis <animi.vulpis@gmail.com>
Helped-by: Johannes Sixt <j6t@kbdg.org>
Signed-off-by: DOAN Tran Cong Danh <congdanhqx@gmail.com>
---
 ref-filter.c             | 19 +++++++++++++++----
 t/t3203-branch-output.sh |  3 ++-
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index 1fc5e9970..b3c2276a5 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -967,7 +967,8 @@ static void find_subpos(const char *buf, unsigned long sz,
 	/* subject is first non-empty line */
 	*sub = buf;
 	/* subject goes to first empty line */
-	while (buf < *sig && *buf && *buf != '\n') {
+	while (buf < *sig && *buf && *buf != '\n'
+	       && !(*buf == '\r' && *(buf + 1) == '\n')) {
 		eol = strchrnul(buf, '\n');
 		if (*eol)
 			eol++;
@@ -975,12 +976,22 @@ static void find_subpos(const char *buf, unsigned long sz,
 	}
 	*sublen = buf - *sub;
 	/* drop trailing newline, if present */
-	if (*sublen && (*sub)[*sublen - 1] == '\n')
+	if (*sublen && (*sub)[*sublen - 1] == '\n') {
 		*sublen -= 1;
+		/* also drop trailing CR before that LF */
+		if ((*sublen) && (*sub)[*sublen - 1] == '\r')
+			*sublen -= 1;
+	}
 
 	/* skip any empty lines */
-	while (*buf == '\n')
-		buf++;
+	while (1) {
+		if (*buf == '\n')
+			buf++;
+		else if (*buf == '\r' && *(buf + 1) == '\n')
+			buf += 2;
+		else
+			break;
+	}
 	*body = buf;
 	*bodylen = strlen(buf);
 	*nonsiglen = *sig - buf;
diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index 5778c0afe..29b392066 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -13,7 +13,8 @@ test_expect_success 'make commits' '
 
 test_expect_success 'make branches' '
 	git branch branch-one &&
-	git branch branch-two HEAD^
+	git branch branch-two $(printf "%s\r\n" one "" line3_long line4 |
+	     git commit-tree HEAD:)
 '
 
 test_expect_success 'make remote branches' '
-- 
2.13.0.67.g10c78a1