[PATCH 1/1] cli/show: avoid empty write to stdout in format_part_raw

[Rob Browning]

Previously (at least) if the input was exactly 4096 bytes long,
notmuch would attempt to fwrite nothing to stdout, but still expected
fwrite to return 1, causing a failure that looked like this:

  $ notmuch show --format=raw id:87o96f1cya.fsf at codeaurora.org
    ...entire message shown as expected..
  Error: Write failed
  $ echo $?
  1

To fix the problem don't call fwrite at all when there's nothing to
write.
---

 Proposed for 0.28.4 -- thanks.

 notmuch-show.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/notmuch-show.c b/notmuch-show.c
index c3a3783a..98b85352 100644
--- a/notmuch-show.c
+++ b/notmuch-show.c
@@ -851,7 +851,7 @@ format_part_raw (unused (const void *ctx), unused (sprinter_t *sp),
 		return NOTMUCH_STATUS_FILE_ERROR;
 	    }
 
-	    if (fwrite (buf, size, 1, stdout) != 1) {
+	    if (size > 0 && fwrite (buf, size, 1, stdout) != 1) {
 		fprintf (stderr, "Error: Write failed\n");
 		fclose (file);
 		return NOTMUCH_STATUS_FILE_ERROR;
-- 
2.20.1