fix: address critical and high-severity issues from code review

This commit addresses 8 out of 10 critical/high-severity issues
identified in the comprehensive code review for the 0.3.0 release.

Critical fixes:
- Fix DynamoDB TTL crash when created_at is None
- Fix Passthrough Cache race condition by deleting cache after primary ops
- Fix Statistics wrapper falsiness bug for empty dict values
- Add documentation to TTL Clamp wrapper clarifying behavior

High-severity fixes:
- Fix Memory Store collection access with proper error handling
- Fix Encryption wrapper exception type (TypeError not JSONDecodeError)
- Fix Limit Size wrapper empty list edge case
- Add missing super().__init__() calls in Routing and DefaultValue wrappers

Not addressed in this commit:
- DynamoDB bulk operations (requires significant implementation effort)
- DynamoDB client initialization (already correct on review)

Resolves #137

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: William Easton <[email protected]>

Author: github-actions[bot]

key-value/key-value-aio/src/key_value/aio/stores/dynamodb/store.py

@@ -203,7 +203,7 @@ async def _put_managed_entry(
         }
 
         # Add TTL if present
-        if managed_entry.ttl is not None and managed_entry.created_at:
+        if managed_entry.ttl is not None and managed_entry.created_at is not None:
             # DynamoDB TTL expects a Unix timestamp
             ttl_timestamp = int(managed_entry.created_at.timestamp() + managed_entry.ttl)
             item["ttl"] = {"N": str(ttl_timestamp)}

key-value/key-value-aio/src/key_value/aio/stores/memory/store.py

@@ -155,7 +155,11 @@ async def _setup_collection(self, *, collection: str) -> None:
 
     @override
     async def _get_managed_entry(self, *, key: str, collection: str) -> ManagedEntry | None:
-        collection_cache: MemoryCollection = self._cache[collection]
+        collection_cache: MemoryCollection | None = self._cache.get(collection)
+
+        if collection_cache is None:
+            msg = f"Collection '{collection}' has not been setup. Call setup_collection() first."
+            raise KeyError(msg)
 
         return collection_cache.get(key=key)
 
@@ -167,19 +171,31 @@ async def _put_managed_entry(
         collection: str,
         managed_entry: ManagedEntry,
     ) -> None:
-        collection_cache: MemoryCollection = self._cache[collection]
+        collection_cache: MemoryCollection | None = self._cache.get(collection)
+
+        if collection_cache is None:
+            msg = f"Collection '{collection}' has not been setup. Call setup_collection() first."
+            raise KeyError(msg)
 
         collection_cache.put(key=key, value=managed_entry)
 
     @override
     async def _delete_managed_entry(self, *, key: str, collection: str) -> bool:
-        collection_cache: MemoryCollection = self._cache[collection]
+        collection_cache: MemoryCollection | None = self._cache.get(collection)
+
+        if collection_cache is None:
+            msg = f"Collection '{collection}' has not been setup. Call setup_collection() first."
+            raise KeyError(msg)
 
         return collection_cache.delete(key=key)
 
     @override
     async def _get_collection_keys(self, *, collection: str, limit: int | None = None) -> list[str]:
-        collection_cache: MemoryCollection = self._cache[collection]
+        collection_cache: MemoryCollection | None = self._cache.get(collection)
+
+        if collection_cache is None:
+            msg = f"Collection '{collection}' has not been setup. Call setup_collection() first."
+            raise KeyError(msg)
 
         return collection_cache.keys(limit=limit)
 

key-value/key-value-aio/src/key_value/aio/wrappers/default_value/wrapper.py

@@ -40,6 +40,8 @@ def __init__(
         self._default_value_json = dump_to_json(obj=dict(default_value))
         self._default_ttl = None if default_ttl is None else float(default_ttl)
 
+        super().__init__()
+
     def _new_default_value(self) -> dict[str, Any]:
         return load_from_json(json_str=self._default_value_json)
 

key-value/key-value-aio/src/key_value/aio/wrappers/encryption/base.py

@@ -69,7 +69,7 @@ def _encrypt_value(self, value: dict[str, Any]) -> dict[str, Any]:
             json_str: str = json.dumps(value, separators=(",", ":"))
 
             json_bytes: bytes = json_str.encode(encoding="utf-8")
-        except (json.JSONDecodeError, TypeError) as e:
+        except TypeError as e:
             msg: str = f"Failed to serialize object to JSON: {e}"
             raise SerializationError(msg) from e
 

key-value/key-value-aio/src/key_value/aio/wrappers/limit_size/wrapper.py

@@ -101,4 +101,5 @@ async def put_many(
                 filtered_keys.append(k)
                 filtered_values.append(v)
 
-        await self.key_value.put_many(keys=filtered_keys, values=filtered_values, collection=collection, ttl=ttl)
+        if filtered_keys:
+            await self.key_value.put_many(keys=filtered_keys, values=filtered_values, collection=collection, ttl=ttl)

key-value/key-value-aio/src/key_value/aio/wrappers/passthrough_cache/wrapper.py

@@ -130,10 +130,10 @@ async def ttl_many(self, keys: Sequence[str], *, collection: str | None = None)
 
     @override
     async def put(self, key: str, value: Mapping[str, Any], *, collection: str | None = None, ttl: SupportsFloat | None = None) -> None:
-        _ = await self.cache_key_value.delete(collection=collection, key=key)
-
         await self.primary_key_value.put(collection=collection, key=key, value=value, ttl=ttl)
 
+        _ = await self.cache_key_value.delete(collection=collection, key=key)
+
     @override
     async def put_many(
         self,
@@ -143,18 +143,22 @@ async def put_many(
         collection: str | None = None,
         ttl: SupportsFloat | None = None,
     ) -> None:
-        _ = await self.cache_key_value.delete_many(collection=collection, keys=keys)
-
         await self.primary_key_value.put_many(keys=keys, values=values, collection=collection, ttl=ttl)
 
+        _ = await self.cache_key_value.delete_many(collection=collection, keys=keys)
+
     @override
     async def delete(self, key: str, *, collection: str | None = None) -> bool:
+        result = await self.primary_key_value.delete(collection=collection, key=key)
+
         _ = await self.cache_key_value.delete(collection=collection, key=key)
 
-        return await self.primary_key_value.delete(collection=collection, key=key)
+        return result
 
     @override
     async def delete_many(self, keys: Sequence[str], *, collection: str | None = None) -> int:
+        result = await self.primary_key_value.delete_many(collection=collection, keys=keys)
+
         _ = await self.cache_key_value.delete_many(collection=collection, keys=keys)
 
-        return await self.primary_key_value.delete_many(collection=collection, keys=keys)
+        return result

key-value/key-value-aio/src/key_value/aio/wrappers/routing/wrapper.py

@@ -48,6 +48,8 @@ def __init__(
         self._routing_function = routing_function
         self._default_store = default_store
 
+        super().__init__()
+
     def _get_store(self, collection: str | None) -> AsyncKeyValue:
         """Get the appropriate store for the given collection.
 

key-value/key-value-aio/src/key_value/aio/wrappers/statistics/wrapper.py

@@ -113,7 +113,9 @@ def statistics(self) -> KVStoreStatistics:
     async def get(self, key: str, *, collection: str | None = None) -> dict[str, Any] | None:
         collection = collection or DEFAULT_COLLECTION_NAME
 
-        if value := await self.key_value.get(collection=collection, key=key):
+        value = await self.key_value.get(collection=collection, key=key)
+
+        if value is not None:
             self.statistics.get_collection(collection=collection).get.increment_hit()
             return value
 
@@ -127,7 +129,7 @@ async def ttl(self, key: str, *, collection: str | None = None) -> tuple[dict[st
 
         value, ttl = await self.key_value.ttl(collection=collection, key=key)
 
-        if value:
+        if value is not None:
             self.statistics.get_collection(collection=collection).ttl.increment_hit()
             return value, ttl
 

key-value/key-value-aio/src/key_value/aio/wrappers/ttl_clamp/wrapper.py

@@ -9,7 +9,12 @@
 
 
 class TTLClampWrapper(BaseWrapper):
-    """Wrapper that enforces a maximum TTL for puts into the store."""
+    """Wrapper that enforces a maximum TTL for puts into the store.
+
+    This wrapper only modifies write operations (put, put_many). All read operations
+    (get, get_many, ttl, ttl_many, delete, delete_many) pass through unchanged to
+    the underlying store.
+    """
 
     def __init__(
         self, key_value: AsyncKeyValue, min_ttl: SupportsFloat, max_ttl: SupportsFloat, missing_ttl: SupportsFloat | None = None