[PATCH] knotty: Improve exception handling

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

Currently, IOErrors are just passed over due to the broken Exception
clause. A command like "bitbake X | <invalid command>" would break stdout
triggering a traceback. With these changes we print the exceptions, shut down
the server gracefully and exit which is a much nicer behaviour and is less
confusion to the user.

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 746dcf4..bb6d4cb 100644
--- a/bitbake/lib/bb/ui/knotty.py
+++ b/bitbake/lib/bb/ui/knotty.py
@@ -508,6 +508,10 @@ def main(server, eventHandler, params, tf = TerminalFilter):
             # ignore interrupted io
             if ioerror.args[0] == 4:
                 pass
+            sys.stderr.write(str(ioerror))
+            if not params.observe_only:
+                _, error = server.runCommand(["stateForceShutdown"])
+            main.shutdown = 2
         except KeyboardInterrupt:
             termfilter.clearFooter()
             if params.observe_only:
@@ -526,7 +530,11 @@ def main(server, eventHandler, params, tf = TerminalFilter):
                     logger.error("Unable to cleanly shutdown: %s" % error)
             main.shutdown = main.shutdown + 1
             pass
-
+        except Exception as e:
+            sys.stderr.write(str(e))
+            if not params.observe_only:
+                _, error = server.runCommand(["stateForceShutdown"])
+            main.shutdown = 2
     summary = ""
     if taskfailures:
         summary += pluralise("\nSummary: %s task failed:",