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

[DOAN Tran Cong Danh]

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.vul...@gmail.com>
Helped-by: Johannes Sixt <j...@kbdg.org>
Signed-off-by: DOAN Tran Cong Danh <congdan...@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