[PATCH 1/4] fast-import: use xsnprintf for writing sha1s

[Jeff King <peff@peff.net>]

When we have to write a sha1 with a newline, we do so by
copying both into a single buffer, so that we can issue a
single write() call.

We use snprintf but don't bother to check the output, since
we know it will fit. However, we should use xsnprintf() in
such a case so that we're notified if our assumption turns
out to be wrong (and to make it easier to audit for
unchecked snprintf calls).

Signed-off-by: Jeff King <peff@peff.net>
---
This is ready for conversion to oid_to_hex, too, but I avoided that
here. The buffer would need to be allocated with the new GIT_MAX_HEXSZ,
which is not yet available. So I figured it was better to leave it than
half-convert it and leave brian wondering whether it's really supposed
to be GIT_MAX_HEXSZ or GIT_SHA1_HEXSZ.

 fast-import.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fast-import.c b/fast-import.c
index 41a539f97..4e0f3f5dd 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -3003,7 +3003,7 @@ static void parse_get_mark(const char *p)
 	if (!oe)
 		die("Unknown mark: %s", command_buf.buf);
 
-	snprintf(output, sizeof(output), "%s\n", sha1_to_hex(oe->idx.sha1));
+	xsnprintf(output, sizeof(output), "%s\n", sha1_to_hex(oe->idx.sha1));
 	cat_blob_write(output, 41);
 }
 
-- 
2.12.1.843.g1937c56c2