feat(integrations): Add unraisable exception integration (#4733)

Adds an uncaught exception integration, enabled by default. The
integration forwards the exception to Sentry only if the exception value
and stacktrace are set.

Closes #374

Author: alexander-alderman-webb

sentry_sdk/integrations/unraisablehook.py

@@ -0,0 +1,53 @@
+import sys
+
+import sentry_sdk
+from sentry_sdk.utils import (
+    capture_internal_exceptions,
+    event_from_exception,
+)
+from sentry_sdk.integrations import Integration
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from typing import Callable
+    from typing import Any
+
+
+class UnraisablehookIntegration(Integration):
+    identifier = "unraisablehook"
+
+    @staticmethod
+    def setup_once():
+        # type: () -> None
+        sys.unraisablehook = _make_unraisable(sys.unraisablehook)
+
+
+def _make_unraisable(old_unraisablehook):
+    # type: (Callable[[sys.UnraisableHookArgs], Any]) -> Callable[[sys.UnraisableHookArgs], Any]
+    def sentry_sdk_unraisablehook(unraisable):
+        # type: (sys.UnraisableHookArgs) -> None
+        integration = sentry_sdk.get_client().get_integration(UnraisablehookIntegration)
+
+        # Note: If  we replace this with ensure_integration_enabled then
+        # we break the exceptiongroup backport;
+        # See: https://github.com/getsentry/sentry-python/issues/3097
+        if integration is None:
+            return old_unraisablehook(unraisable)
+
+        if unraisable.exc_value and unraisable.exc_traceback:
+            with capture_internal_exceptions():
+                event, hint = event_from_exception(
+                    (
+                        unraisable.exc_type,
+                        unraisable.exc_value,
+                        unraisable.exc_traceback,
+                    ),
+                    client_options=sentry_sdk.get_client().options,
+                    mechanism={"type": "unraisablehook", "handled": False},
+                )
+                sentry_sdk.capture_event(event, hint=hint)
+
+        return old_unraisablehook(unraisable)
+
+    return sentry_sdk_unraisablehook

tests/integrations/unraisablehook/test_unraisablehook.py

@@ -0,0 +1,56 @@
+import pytest
+import sys
+import subprocess
+
+from textwrap import dedent
+
+
+TEST_PARAMETERS = [
+    ("", "HttpTransport"),
+    ('_experiments={"transport_http2": True}', "Http2Transport"),
+]
+
+minimum_python_38 = pytest.mark.skipif(
+    sys.version_info < (3, 8),
+    reason="The unraisable exception hook is only available in Python 3.8 and above.",
+)
+
+
+@minimum_python_38
+@pytest.mark.parametrize("options, transport", TEST_PARAMETERS)
+def test_unraisablehook(tmpdir, options, transport):
+    app = tmpdir.join("app.py")
+    app.write(
+        dedent(
+            """
+    from sentry_sdk import init, transport
+    from sentry_sdk.integrations.unraisablehook import UnraisablehookIntegration
+
+    class Undeletable:
+        def __del__(self):
+            1 / 0
+
+    def capture_envelope(self, envelope):
+        print("capture_envelope was called")
+        event = envelope.get_event()
+        if event is not None:
+            print(event)
+
+    transport.{transport}.capture_envelope = capture_envelope
+
+    init("http://foobar@localhost/123", integrations=[UnraisablehookIntegration()], {options})
+
+    undeletable = Undeletable()
+    del undeletable
+    """.format(
+                transport=transport, options=options
+            )
+        )
+    )
+
+    output = subprocess.check_output(
+        [sys.executable, str(app)], stderr=subprocess.STDOUT
+    )
+
+    assert b"ZeroDivisionError" in output
+    assert b"capture_envelope was called" in output

tests/test_basics.py

@@ -870,6 +870,7 @@ def foo(event, hint):
         (["celery"], "sentry.python"),
         (["dedupe"], "sentry.python"),
         (["excepthook"], "sentry.python"),
+        (["unraisablehook"], "sentry.python"),
         (["executing"], "sentry.python"),
         (["modules"], "sentry.python"),
         (["pure_eval"], "sentry.python"),