(read_process_output): Don't run a filter if the code

decoder produces nothing but carryover.

1 files changed, 6 insertions, 5 deletions

diff --git a/src/process.c b/src/process.c
index c91ab2c24fc..1394b6b8b3c 100644
--- a/src/process.c
+++ b/src/process.c
@@ -3009,11 +3009,12 @@ read_process_output (proc, channel)
       XSETINT (p->decoding_carryover, carryover);
       nbytes = STRING_BYTES (XSTRING (text));
       nchars = XSTRING (text)->size;
-      internal_condition_case_1 (read_process_output_call,
-                                 Fcons (outstream,
-                                        Fcons (proc, Fcons (text, Qnil))),
-                                 !NILP (Vdebug_on_error) ? Qnil : Qerror,
-                                 read_process_output_error_handler);
+      if (nbytes > 0)
+        internal_condition_case_1 (read_process_output_call,
+                                   Fcons (outstream,
+                                          Fcons (proc, Fcons (text, Qnil))),
+                                   !NILP (Vdebug_on_error) ? Qnil : Qerror,
+                                   read_process_output_error_handler);
 
       /* If we saved the match data nonrecursively, restore it now.  */
       restore_match_data ();