crash reporter: add EarlyExceptionsQueue

`util.send_exception_to_crash_reporter` is now useful and can be transparently
used even before the exception hook is set up.

electrum/base_crash_reporter.py

@@ -24,6 +24,7 @@ import json
 import locale
 import traceback
 import sys
+import queue
 
 from .version import ELECTRUM_VERSION
 from . import constants
@@ -131,6 +132,43 @@ class BaseCrashReporter(Logger):
         raise NotImplementedError
 
 
+class EarlyExceptionsQueue:
+    """Helper singleton for explicitly sending exceptions to crash reporter.
+
+    Typically the GUIs set up an "exception hook" that catches all otherwise
+    uncaught exceptions (which unroll the stack of a thread completely).
+    This class provides methods to report *any* exception, and queueing logic
+    that delays processing until the exception hook is set up.
+    """
+
+    _is_exc_hook_ready = False
+    _exc_queue = queue.Queue()
+
+    @classmethod
+    def set_hook_as_ready(cls):
+        if cls._is_exc_hook_ready:
+            return
+        cls._is_exc_hook_ready = True
+        while cls._exc_queue.qsize() > 0:
+            e = cls._exc_queue.get()
+            cls._send_exception_to_crash_reporter(e)
+
+    @classmethod
+    def send_exception_to_crash_reporter(cls, e: BaseException):
+        if cls._is_exc_hook_ready:
+            cls._send_exception_to_crash_reporter(e)
+        else:
+            cls._exc_queue.put(e)
+
+    @staticmethod
+    def _send_exception_to_crash_reporter(e: BaseException):
+        assert EarlyExceptionsQueue._is_exc_hook_ready
+        sys.excepthook(type(e), e, e.__traceback__)
+
+
+send_exception_to_crash_reporter = EarlyExceptionsQueue.send_exception_to_crash_reporter
+
+
 def trigger_crash():
     # note: do not change the type of the exception, the message,
     # or the name of this method. All reports generated through this

electrum/daemon.py

@@ -487,8 +487,6 @@ class Daemon(Logger):
             if self.config.get('use_gossip', False):
                 self.network.start_gossip()
 
-        self.exception = None  # type: Optional[Exception]
-
         self._stop_entered = False
         self._stopping_soon_or_errored = threading.Event()
         self._stopped_event = threading.Event()
@@ -508,7 +506,6 @@ class Daemon(Logger):
             raise
         except Exception as e:
             self.logger.exception("taskgroup died.")
-            self.exception = e
             util.send_exception_to_crash_reporter(e)
         finally:
             self.logger.info("taskgroup stopped.")

electrum/gui/kivy/uix/dialogs/crash_reporter.py

@@ -12,7 +12,7 @@ from kivy.utils import platform
 
 from electrum.gui.kivy.i18n import _
 
-from electrum.base_crash_reporter import BaseCrashReporter
+from electrum.base_crash_reporter import BaseCrashReporter, EarlyExceptionsQueue
 from electrum.logging import Logger
 
 
@@ -185,6 +185,7 @@ class ExceptionHook(base.ExceptionHandler, Logger):
         base.ExceptionManager.add_handler(self)
         # For everything else:
         sys.excepthook = lambda exctype, value, tb: self.handle_exception(value)
+        EarlyExceptionsQueue.set_hook_as_ready()
 
     def handle_exception(self, _inst):
         exc_info = sys.exc_info()

electrum/gui/qt/__init__.py

@@ -403,8 +403,6 @@ class ElectrumGui(Logger):
         signal.signal(signal.SIGINT, lambda *args: self.app.quit())
         # hook for crash reporter
         Exception_Hook.maybe_setup(config=self.config)
-        if self.daemon.exception:  # if daemon errored too early, replay that now:
-            send_exception_to_crash_reporter(self.daemon.exception)
         # first-start network-setup
         try:
             self.init_network()

electrum/gui/qt/exception_window.py

@@ -31,7 +31,7 @@ from PyQt5.QtWidgets import (QWidget, QLabel, QPushButton, QTextEdit,
                              QMessageBox, QHBoxLayout, QVBoxLayout)
 
 from electrum.i18n import _
-from electrum.base_crash_reporter import BaseCrashReporter
+from electrum.base_crash_reporter import BaseCrashReporter, EarlyExceptionsQueue
 from electrum.logging import Logger
 from electrum import constants
 from electrum.network import Network
@@ -172,6 +172,7 @@ class Exception_Hook(QObject, Logger):
 
         sys.excepthook = self.handler
         self._report_exception.connect(_show_window)
+        EarlyExceptionsQueue.set_hook_as_ready()
 
     @classmethod
     def maybe_setup(cls, *, config: 'SimpleConfig', wallet: 'Abstract_Wallet' = None) -> None:

electrum/util.py

@@ -1112,7 +1112,8 @@ def setup_thread_excepthook():
 
 
 def send_exception_to_crash_reporter(e: BaseException):
-    sys.excepthook(type(e), e, e.__traceback__)
+    from .base_crash_reporter import send_exception_to_crash_reporter
+    send_exception_to_crash_reporter(e)
 
 
 def versiontuple(v):