fix: resolve critical issues in memory provider error handling

- Fix factory return value being discarded in memory.py
- Remove silent exception swallowing that broke backward compatibility
- Fix datetime import bug in MongoDB adapter (datetime.timezone.utc)
- Preserve original error propagation for misconfigured providers
- Ensure factory-created adapters are properly used when successful

Fixes issues identified by Greptile and CodeRabbit reviewers.

Co-authored-by: Mervin Praison <MervinPraison@users.noreply.github.com>

Author: praisonai-triage-agent[bot]

src/praisonai-agents/praisonaiagents/memory/adapters/factories.py

@@ -364,15 +364,15 @@ def _create_indexes(self):
 
     def store_short_term(self, text: str, metadata: Optional[Dict[str, Any]] = None, **kwargs) -> str:
         """Store in MongoDB short-term collection."""
-        from datetime import datetime
+        from datetime import datetime, timezone
         import time
 
         doc_id = str(time.time_ns())
         doc = {
             "_id": doc_id,
             "content": text,
             "metadata": metadata or {},
-            "created_at": datetime.now(datetime.timezone.utc),
+            "created_at": datetime.now(timezone.utc),
             "memory_type": "short_term"
         }
 
@@ -396,15 +396,15 @@ def search_short_term(self, query: str, limit: int = 5, **kwargs) -> List[Dict[s
 
     def store_long_term(self, text: str, metadata: Optional[Dict[str, Any]] = None, **kwargs) -> str:
         """Store in MongoDB long-term collection."""
-        from datetime import datetime
+        from datetime import datetime, timezone
         import time
 
         doc_id = str(time.time_ns())
         doc = {
             "_id": doc_id,
             "content": text,
             "metadata": metadata or {},
-            "created_at": datetime.now(datetime.timezone.utc),
+            "created_at": datetime.now(timezone.utc),
             "memory_type": "long_term"
         }
 

src/praisonai-agents/praisonaiagents/memory/memory.py

@@ -172,16 +172,22 @@ def _init_protocol_driven_memory(self):
                         "mongodb": create_mongodb_memory_adapter,
                     }
                     if adapter_name in factory_map:
-                        # Call the factory to trigger the ImportError with installation hint
+                        # Call the factory to get ImportError with installation hint
+                        # or capture successful adapter creation
                         adapter_config = self._get_adapter_config_for_provider(adapter_name)
-                        factory_map[adapter_name](**adapter_config)
+                        adapter = factory_map[adapter_name](**adapter_config)
                 except ImportError:
-                    # Re-raise the ImportError with installation instructions
+                    # Re-raise ImportError with installation instructions
                     raise
-                except Exception:
-                    # Fall through to fallback behavior for other errors
-                    pass
+                # All other exceptions (e.g., ValueError for missing API key) 
+                # propagate naturally, preserving backward compatibility
 
+            # If factory succeeded, use that adapter
+            if adapter is not None:
+                self.memory_adapter = adapter
+                self.provider = adapter_name
+                return
+                
             # Fallback to first available adapter
             self._log_verbose(f"Provider '{adapter_name}' not available, trying fallbacks")
             # Try each fallback preference individually