refactor: replace dataclasses.replace with explicit factory methods

- Add Operation.from_existing() classmethod
- Add StepDetails.from_existing() and CallbackDetails.from_existing() factory methods
- Replace all dataclasses.replace() calls with explicit constructors
- Add test coverage for new factory methods

Author: Rares Polenciuc

examples/src/wait_for_callback/wait_for_callback.py

@@ -10,6 +10,7 @@ def external_system_call(_callback_id: str) -> None:
     """Simulate calling an external system with callback ID."""
     # In real usage, this would make an API call to an external system
     # passing the callback_id for the system to call back when done
+    print(_callback_id)
 
 
 @durable_execution

src/aws_durable_execution_sdk_python_testing/execution.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 import json
-from dataclasses import replace
+
 from datetime import UTC, datetime
 from enum import Enum
 from threading import Lock
@@ -13,12 +13,14 @@
     InvocationStatus,
 )
 from aws_durable_execution_sdk_python.lambda_service import (
+    CallbackDetails,
     ErrorObject,
     ExecutionDetails,
     Operation,
     OperationStatus,
     OperationType,
     OperationUpdate,
+    StepDetails,
 )
 
 from aws_durable_execution_sdk_python_testing.exceptions import (
@@ -289,7 +291,7 @@ def complete_wait(self, operation_id: str) -> Operation:
         with self._state_lock:
             self._token_sequence += 1
             # Build and assign updated operation
-            self.operations[index] = replace(
+            self.operations[index] = Operation.from_existing(
                 operation,
                 status=OperationStatus.SUCCEEDED,
                 end_timestamp=datetime.now(UTC),
@@ -316,12 +318,12 @@ def complete_retry(self, operation_id: str) -> Operation:
             # Build updated step_details with cleared next_attempt_timestamp
             new_step_details = None
             if operation.step_details:
-                new_step_details = replace(
+                new_step_details = StepDetails.from_existing(
                     operation.step_details, next_attempt_timestamp=None
                 )
 
             # Build updated operation
-            updated_operation = replace(
+            updated_operation = Operation.from_existing(
                 operation, status=OperationStatus.READY, step_details=new_step_details
             )
 
@@ -342,12 +344,12 @@ def complete_callback_success(
             self._token_sequence += 1
             updated_callback_details = None
             if operation.callback_details:
-                updated_callback_details = replace(
+                updated_callback_details = CallbackDetails.from_existing(
                     operation.callback_details,
                     result=result.decode() if result else None,
                 )
 
-            self.operations[index] = replace(
+            self.operations[index] = Operation.from_existing(
                 operation,
                 status=OperationStatus.SUCCEEDED,
                 end_timestamp=datetime.now(UTC),
@@ -369,11 +371,11 @@ def complete_callback_failure(
             self._token_sequence += 1
             updated_callback_details = None
             if operation.callback_details:
-                updated_callback_details = replace(
+                updated_callback_details = CallbackDetails.from_existing(
                     operation.callback_details, error=error
                 )
 
-            self.operations[index] = replace(
+            self.operations[index] = Operation.from_existing(
                 operation,
                 status=OperationStatus.FAILED,
                 end_timestamp=datetime.now(UTC),
@@ -386,7 +388,7 @@ def _end_execution(self, status: OperationStatus) -> None:
         execution_op: Operation = self.get_operation_execution_started()
         if execution_op.operation_type == OperationType.EXECUTION:
             with self._state_lock:
-                self.operations[0] = replace(
+                self.operations[0] = Operation.from_existing(
                     execution_op,
                     status=status,
                     end_timestamp=datetime.now(UTC),

src/aws_durable_execution_sdk_python_testing/model.py

@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 import datetime
-from dataclasses import dataclass, replace
+from dataclasses import dataclass
 from enum import Enum
 from typing import Any
 
@@ -2547,7 +2547,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
         # Merge with previous operation if it exists
         # Most fields are immutable, so they get preserved from previous events
         if previous_operation:
-            operation = replace(
+            operation = Operation.from_existing(
                 operation,
                 name=operation.name or previous_operation.name,
                 parent_id=operation.parent_id or previous_operation.parent_id,
@@ -2564,9 +2564,13 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
 
         # Set timestamps based on event configuration
         if event_config.is_start_event:
-            operation = replace(operation, start_timestamp=event.event_timestamp)
+            operation = Operation.from_existing(
+                operation, start_timestamp=event.event_timestamp
+            )
         if event_config.is_end_event:
-            operation = replace(operation, end_timestamp=event.event_timestamp)
+            operation = Operation.from_existing(
+                operation, end_timestamp=event.event_timestamp
+            )
 
         # Add operation-specific details incrementally
         # Each event type contributes only the fields it has
@@ -2577,7 +2581,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
             and event.execution_started_details
             and event.execution_started_details.input
         ):
-            operation = replace(
+            operation = Operation.from_existing(
                 operation,
                 execution_details=ExecutionDetails(
                     input_payload=event.execution_started_details.input.payload
@@ -2613,7 +2617,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
             ):
                 error = event.callback_timed_out_details.error.payload
 
-            operation = replace(
+            operation = Operation.from_existing(
                 operation,
                 callback_details=CallbackDetails(
                     callback_id=callback_id,
@@ -2655,7 +2659,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
                             seconds=event.step_failed_details.retry_details.next_attempt_delay_seconds
                         )
 
-            operation = replace(
+            operation = Operation.from_existing(
                 operation,
                 step_details=StepDetails(
                     result=result_val,
@@ -2667,7 +2671,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
 
         # WAIT details
         if operation_type == OperationType.WAIT and event.wait_started_details:
-            operation = replace(
+            operation = Operation.from_existing(
                 operation,
                 wait_details=WaitDetails(
                     scheduled_end_timestamp=event.wait_started_details.scheduled_end_timestamp
@@ -2680,15 +2684,15 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
                 event.context_succeeded_details
                 and event.context_succeeded_details.result
             ):
-                operation = replace(
+                operation = Operation.from_existing(
                     operation,
                     context_details=ContextDetails(
                         result=event.context_succeeded_details.result.payload,
                         error=None,
                     ),
                 )
             elif event.context_failed_details and event.context_failed_details.error:
-                operation = replace(
+                operation = Operation.from_existing(
                     operation,
                     context_details=ContextDetails(
                         result=None,
@@ -2702,7 +2706,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
                 event.chained_invoke_succeeded_details
                 and event.chained_invoke_succeeded_details.result
             ):
-                operation = replace(
+                operation = Operation.from_existing(
                     operation,
                     chained_invoke_details=ChainedInvokeDetails(
                         result=event.chained_invoke_succeeded_details.result.payload,
@@ -2713,7 +2717,7 @@ def events_to_operations(events: list[Event]) -> list[Operation]:
                 event.chained_invoke_failed_details
                 and event.chained_invoke_failed_details.error
             ):
-                operation = replace(
+                operation = Operation.from_existing(
                     operation,
                     chained_invoke_details=ChainedInvokeDetails(
                         result=None,