fix(reports): don't let PlaywrightTimeout=Exception fallback swallow unrelated errors

CI failures on this branch traced to two issues:

1. take_tiled_screenshot()'s outer `except PlaywrightTimeout: raise` /
   `except Exception: return None` pair assumed PlaywrightTimeout is always
   distinguishable from a generic Exception. It isn't: when the playwright
   package isn't installed, `PlaywrightTimeout = Exception` (see the
   try/except ImportError above the function). In that case *any* exception
   -- not just our own deliberate per-tile readiness-timeout raise --
   matched `except PlaywrightTimeout` first and incorrectly propagated
   instead of degrading to `None` like every other unexpected error (e.g.
   the initial dashboard element never appearing). This is exactly what
   unit-tests hit in CI (no playwright installed there), turning
   `test_element_not_found_returns_none` and `test_exception_handling_*`
   into uncaught-exception failures.

   Fixed by tracking the "this is our own readiness timeout" case with an
   explicit boolean flag set right before the inner `raise`, instead of
   relying on exception-type dispatch that can't tell the two cases apart
   when the import fallback is active.

2. `execute.py` now always passes `log_context=...` to
   `screenshot.get_screenshot(...)`. One integration test
   (`test_email_chart_report_schedule_alpha_owner`) mocks
   `ChartScreenshot.get_screenshot` with a side_effect function whose
   signature only accepted `user`, so the new kwarg raised a TypeError,
   caught by execute.py's own error handling and reported as a
   ReportScheduleScreenshotFailedError in test-mysql/postgres/sqlite. Fixed
   by accepting the new `log_context` keyword in that test's side_effect
   signature. Confirmed this was the only such call site in the test suite
   (all others use plain `.return_value`/exception-instance side effects,
   which don't care about the new kwarg).

Verified locally with and without playwright installed, matching both
conditions CI exercises.

Co-Authored-By: Claude <noreply@anthropic.com>

superset/utils/screenshot_utils.py

@@ -184,6 +184,16 @@ def take_tiled_screenshot(
         Combined screenshot bytes or None if failed
     """
     context_suffix = f" [{log_context}]" if log_context else ""
+    # Set right before re-raising the per-tile readiness timeout below, and
+    # checked in the except block at the bottom of this function. Deciding
+    # whether to propagate via `isinstance(e, PlaywrightTimeout)` would be
+    # unreliable: when the playwright package isn't installed,
+    # `PlaywrightTimeout` is aliased to the bare `Exception` class (see the
+    # try/except ImportError above this function), which would make *any*
+    # exception -- not just our own deliberate readiness-timeout raise --
+    # match `except PlaywrightTimeout` and incorrectly propagate instead of
+    # degrading to `None` like every other unexpected error in this function.
+    readiness_timeout = False
     try:
         # Get the target element
         element = page.locator(f".{element_name}")
@@ -263,6 +273,7 @@ def take_tiled_screenshot(
                     context_suffix,
                     unready_chart_holders,
                 )
+                readiness_timeout = True
                 raise
             else:
                 elapsed = time.monotonic() - tile_wait_start
@@ -328,13 +339,15 @@ def take_tiled_screenshot(
 
         return combined_screenshot
 
-    except PlaywrightTimeout:
-        # Let per-tile readiness timeouts propagate so the caller fails the
-        # report instead of silently falling back to a degraded screenshot.
-        raise
     except Exception as e:
-        # Unlike the readiness-timeout warning above, this is a genuine
-        # system-level fault (unexpected error, not a customer chart taking
-        # too long to load), so it stays at ERROR/exception level.
+        if readiness_timeout:
+            # Let the per-tile readiness timeout propagate so the caller
+            # fails the report instead of silently falling back to a
+            # degraded screenshot -- already logged as a WARNING above.
+            raise
+        # Any other exception is a genuine system-level fault (or a setup
+        # failure unrelated to chart readiness, e.g. the dashboard element
+        # itself never appearing), not a customer chart taking too long to
+        # load, so it stays at ERROR/exception level.
         logger.exception("Tiled screenshot failed: %s%s", e, context_suffix)
         return None

tests/integration_tests/reports/commands_tests.py

@@ -826,7 +826,9 @@ def test_email_chart_report_schedule_alpha_owner(
     # setup screenshot mock
     username = ""
 
-    def _screenshot_side_effect(user: User) -> Optional[bytes]:
+    def _screenshot_side_effect(
+        user: User, log_context: Optional[str] = None
+    ) -> Optional[bytes]:
         nonlocal username
         username = user.username