Add `.cancel()` log around `_async_main()` KBI-exit

piker/ui/_app.py

@@ -181,7 +181,14 @@ async def _async_main(
             ):
                 # remove startup status text
                 starting_done()
+                try:
                     await trio.sleep_forever()
+                except KeyboardInterrupt as _kbi:
+                    log.cancel(
+                        f'User canceled Qt app.\n'
+                        f'{_kbi!r}'
+                    )
+                    raise _kbi
 
 
 def _main(

piker/ui/_style.py

@@ -1,5 +1,5 @@
 # piker: trading gear for hackers
-# Copyright (C) Tyler Goodlet (in stewardship for piker0)
+# Copyright (C) Tyler Goodlet (in stewardship for pikers)
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by

piker/ui/_window.py

@@ -217,8 +217,14 @@ class MainWindow(QMainWindow):
         '''Cancel the root actor asap.
 
         '''
-        # raising KBI seems to get intercepted by by Qt so just use the system.
-        os.kill(os.getpid(), signal.SIGINT)
+        # raising a KBI seems to get intercepted by Qt, soo just use OS ??
+        # TODO XXX! seems to sometimes cause Qt core dumps if you
+        # cancel during chart bootup..?
+        # -[ ] find a better/more-correct cancellation API in Qt?
+        os.kill(
+            os.getpid(),
+            signal.SIGINT,
+        )
 
     @property
     def status_bar(self) -> QStatusBar: