[PATCH] knotty: Cleanup error/interruption handling

[Richard Purdie <richard.purdie@linuxfoundation.org>]

Only display a CommandFailed ERROR: message if there is an error to display.

Only display an errors summary if we actually displayed errors.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
diff --git a/bitbake/lib/bb/ui/knotty.py b/bitbake/lib/bb/ui/knotty.py
index f706b97..35590a2 100644
--- a/bitbake/lib/bb/ui/knotty.py
+++ b/bitbake/lib/bb/ui/knotty.py
@@ -405,8 +405,9 @@ def main(server, eventHandler, params, tf = TerminalFilter):
 
             if isinstance(event, bb.command.CommandFailed):
                 return_value = event.exitcode
-                errors = errors + 1
-                logger.error("Command execution failed: %s", event.error)
+                if event.error:
+                    errors = errors + 1
+                    logger.error("Command execution failed: %s", event.error)
                 main.shutdown = 2
                 continue
             if isinstance(event, bb.command.CommandExit):
@@ -520,7 +521,7 @@ def main(server, eventHandler, params, tf = TerminalFilter):
     if warnings:
         summary += pluralise("\nSummary: There was %s WARNING message shown.",
                              "\nSummary: There were %s WARNING messages shown.", warnings)
-    if return_value:
+    if return_value and errors:
         summary += pluralise("\nSummary: There was %s ERROR message shown, returning a non-zero exit code.",
                              "\nSummary: There were %s ERROR messages shown, returning a non-zero exit code.", errors)
     if summary: