fix linter type errors

Author: DavidBuchanan314

.vscode/settings.json

@@ -1,4 +1,5 @@
 {
 	"python.testing.unittestEnabled": true,
-	"python.testing.pytestEnabled": false
+	"python.testing.pytestEnabled": false,
+	"python-envs.defaultEnvManager": "ms-python.python:system"
 }

src/atmst/mst/node.py

@@ -5,7 +5,7 @@
 from itertools import takewhile
 from dataclasses import dataclass
 
-from typing import TYPE_CHECKING, Tuple, Optional
+from typing import TYPE_CHECKING, Tuple, Optional, List
 if TYPE_CHECKING: # Self doesn't exist <3.11
 	from typing import Self
 
@@ -24,9 +24,9 @@ class MSTNode:
 	If a method is implemented in this class, it's because it's a function/property
 	of a single node, as opposed to a whole tree
 	"""
-	keys: Tuple[str] # collection/rkey
-	vals: Tuple[CID] # record CIDs
-	subtrees: Tuple[Optional[CID]] # a None value represents an empty subtree
+	keys: Tuple[str, ...] # collection/rkey
+	vals: Tuple[CID, ...] # record CIDs
+	subtrees: Tuple[Optional[CID], ...] # a None value represents an empty subtree
 
 
 	# NB: __init__ is auto-generated by dataclass decorator
@@ -86,17 +86,31 @@ def serialised(self) -> bytes:
 	@classmethod
 	def deserialise(cls, data: bytes) -> "Self":
 		cbor = decode_dag_cbor(data)
+		if not isinstance(cbor, dict):
+			raise ValueError("malformed MST node")
 		if len(cbor) != 2: # e, l
 			raise ValueError("malformed MST node")
-		subtrees = [cbor["l"]]
-		keys = []
-		vals = []
+		l = cbor["l"]
+		if not isinstance(l, (CID, None.__class__)):
+			raise ValueError("malformed MST node")
+		subtrees: List[CID | None] = [l]
+		keys: List[str] = []
+		vals: List[CID] = []
 		prev_key = b""
-		for e in cbor["e"]: # TODO: make extra sure that these checks are watertight wrt non-canonical representations
+		es = cbor["e"]
+		if not isinstance(es, list):
+			raise ValueError("malformed MST node")
+		for e in es: # TODO: make extra sure that these checks are watertight wrt non-canonical representations
+			if not isinstance(e, dict):
+				raise ValueError("malformed MST node")
 			if len(e) != 4: # k, p, t, v
 				raise ValueError("malformed MST node")
-			prefix_len: int = e["p"]
-			suffix: bytes = e["k"]
+			prefix_len = e["p"]
+			if not isinstance(prefix_len, int):
+				raise ValueError("malformed MST node")
+			suffix = e["k"]
+			if not isinstance(suffix, bytes):
+				raise ValueError("malformed MST node")
 			if prefix_len > len(prev_key):
 				raise ValueError("invalid MST key prefix len")
 			if prev_key[prefix_len:prefix_len+1] == suffix[:1]:
@@ -105,8 +119,14 @@ def deserialise(cls, data: bytes) -> "Self":
 			if this_key <= prev_key:
 				raise ValueError("invalid MST key sort order")
 			keys.append(this_key.decode())
-			vals.append(e["v"])
-			subtrees.append(e["t"])
+			v = e["v"]
+			if not isinstance(v, CID):
+				raise ValueError("invalid MST key sort order")
+			vals.append(v)
+			t = e["t"]
+			if not isinstance(t, CID):
+				raise ValueError("invalid MST key sort order")
+			subtrees.append(t)
 			prev_key = this_key
 
 		return cls(

src/atmst/mst/node_store.py

@@ -14,7 +14,7 @@ class NodeStore:
 	for loading and storing MSTNodes
 	"""
 	bs: BlockStore
-	cache: Dict[Optional[CID], MSTNode]
+	cache: LRU[Optional[CID], MSTNode]
 
 	def __init__(self, bs: BlockStore) -> None:
 		self.bs = bs

src/atmst/mst/node_walker.py

@@ -50,7 +50,7 @@ def __init__(self,
 		self.ns = ns
 		self.trusted = trusted
 		node = MSTNode.empty_root() if root_cid is None else self.ns.get_node(root_cid)
-		self.root_height = node.maybe_height if root_height is None else root_height
+		self.root_height = node.definitely_height() if root_height is None else root_height
 		if self.root_height is None:
 			raise ValueError("indeterminate node height - pass it in if you know it")
 		self.stack = [self.StackFrame(
@@ -61,7 +61,7 @@ def __init__(self,
 		)]
 
 	def subtree_walker(self) -> "Self":
-		return NodeWalker(
+		return self.__class__(
 			self.ns,
 			self.subtree,
 			self.lpath,
@@ -147,6 +147,7 @@ def next_kv(self) -> Tuple[str, CID]:
 		while self.subtree: # recurse down every subtree
 			self.down()
 		self.right_or_up()
+		assert self.lval is not None
 		return self.lpath, self.lval # the kv pair we just jumped over
 
 	# iterate over every k/v pair in key-sorted order