fix: correct retry_on_exceptions logic to properly handle custom exceptions

The previous logic required _is_transient_error() to be true in all cases,
effectively ignoring the retry_on_exceptions parameter. Now the plugin will
retry if the error is either in retry_on_exceptions OR is a transient error.

Added test case to verify custom exception types trigger retry correctly.

Author: chillum-codeX

src/google/adk_community/plugins/llm_resilience_plugin.py

@@ -168,19 +168,14 @@ async def on_model_error_callback(
       error: Exception,
   ) -> Optional[LlmResponse]:
     """Handle model errors with retry and fallback logic."""
-    # Decide whether to handle this error
-    if self.retry_on_exceptions is not None and not isinstance(
-        error, self.retry_on_exceptions
-    ):
-      # If user provided an explicit exception tuple and it doesn't match,
-      # optionally still retry on transient HTTP-ish errors.
-      if not _is_transient_error(error):
-        return None
-    else:
-      # If user did not provide explicit list, rely on our transient heuristic
-      if not _is_transient_error(error):
-        # Non-transient error → don't handle
-        return None
+    # Decide whether to handle this error:
+    # Retry if error is in retry_on_exceptions OR is a transient error
+    if self.retry_on_exceptions and isinstance(error, self.retry_on_exceptions):
+      # User explicitly wants to retry on this exception type.
+      pass
+    elif not _is_transient_error(error):
+      # Not an explicit exception and not a transient error, so don't handle.
+      return None
 
     # Attempt retries on the same model
     response = await self._retry_same_model(

tests/unittests/plugins/test_llm_resilience_plugin.py

@@ -183,3 +183,38 @@ class NonTransientError(RuntimeError):
         error=NonTransientError("boom"),
     )
     self.assertIsNone(result)
+
+  async def test_custom_retry_on_exceptions(self):
+    """Test that custom exception types in retry_on_exceptions trigger retry."""
+    agent = LlmAgent(name="agent", model=SimpleSuccessModel())
+    invocation_context = await create_invocation_context(agent)
+
+    class CustomError(Exception):
+      pass
+
+    # Plugin configured to retry on CustomError (which is NOT a transient error)
+    plugin = LlmResiliencePlugin(
+        max_retries=2,
+        retry_on_exceptions=(CustomError,),
+    )
+
+    llm_request = LlmRequest(
+        contents=[
+            types.Content(
+                role="user", parts=[types.Part.from_text(text="hello")]
+            )
+        ]
+    )
+
+    # CustomError should trigger retry even though it's not transient
+    result = await plugin.on_model_error_callback(
+        callback_context=invocation_context,
+        llm_request=llm_request,
+        error=CustomError("custom failure"),
+    )
+
+    self.assertIsNotNone(result)
+    self.assertIsInstance(result, LlmResponse)
+    self.assertEqual(
+        result.content.parts[0].text.strip(), "final response from mock"
+    )