[PATCH] blame: handle broken commit headers gracefully

["René Scharfe" <rene.scharfe@lsrfire.ath.cx>]

split_ident_line() can leave us with the pointers date_begin, date_end,
tz_begin and tz_end all set to NULL.  Check them before use and supply
the same fallback values as in the case of a negative return code from
split_ident_line().

The "(unknown)" is not actually shown in the output, though, because it
will be converted to a number (zero) eventually.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
---
Minimal patch, test case missing.  It's a bit sad that the old commit
parser of blame handled Ivan's specific corruption (extra "-<>" after
email) gracefully because it used the spaces as cutting points instead
of "<" and ">".

 builtin/blame.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/builtin/blame.c b/builtin/blame.c
index 86100e9..7770781 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -1375,10 +1375,15 @@ static void get_ac_line(const char *inbuf, const char *what,
 	maillen = ident.mail_end - ident.mail_begin;
 	mailbuf = ident.mail_begin;
 
-	*time = strtoul(ident.date_begin, NULL, 10);
+	if (ident.date_begin && ident.date_end)
+		*time = strtoul(ident.date_begin, NULL, 10);
+	else
+		*time = 0;
 
-	len = ident.tz_end - ident.tz_begin;
-	strbuf_add(tz, ident.tz_begin, len);
+	if (ident.tz_begin && ident.tz_end)
+		strbuf_add(tz, ident.tz_begin, ident.tz_end - ident.tz_begin);
+	else
+		strbuf_addstr(tz, "(unknown)");
 
 	/*
 	 * Now, convert both name and e-mail using mailmap
-- 
1.8.2.1