fix: compatibility with python 3.9+ generics and strict type hints

Author: ygstudio-game

data_structures/hashing/coalesced_hashing.py

@@ -2,21 +2,21 @@
 """
 Coalesced hashing (hybrid of open addressing + chaining inside the table).
 
-Reference: https://en.wikipedia.org/wiki/Hash_table#Coalesced_hashing
+Reference: [https://en.wikipedia.org/wiki/Hash_table#Coalesced_hashing](https://en.wikipedia.org/wiki/Hash_table#Coalesced_hashing)
 """
 
 from __future__ import annotations
 
 from collections.abc import Iterator, MutableMapping
 from dataclasses import dataclass
-from typing import TypeVar
+from typing import Generic, TypeVar
 
 KEY = TypeVar("KEY")
 VAL = TypeVar("VAL")
 
 
 @dataclass(slots=True)
-class _Node[KEY, VAL]:
+class _Node(Generic[KEY, VAL]):  # noqa: UP046
     key: KEY
     val: VAL
     next: int  # -1 means end of chain
@@ -83,18 +83,18 @@ def __setitem__(self, key: KEY, val: VAL) -> None:
         # Search chain for update.
         cur = home
         while True:
-            n = self._table[cur]
-            if n is None:
+            # Explicitly type the current node to satisfy mypy
+            current_node = self._table[cur]
+            if current_node is None:
+                # Should not happen if logic is correct, but handles None safety
                 break
-            # FIX: Ensure n is not None before access
-            assert n is not None
 
-            if n.key == key:
-                n.val = val
+            if current_node.key == key:
+                current_node.val = val
                 return
-            if n.next == -1:
+            if current_node.next == -1:
                 break
-            cur = n.next
+            cur = current_node.next
 
         # Insert new node at a free slot and link it.
         free = self._find_free_from_end()
@@ -105,10 +105,10 @@ def __setitem__(self, key: KEY, val: VAL) -> None:
 
         self._table[free] = _Node(key, val, -1)
 
-        # FIX: Ensure we are linking from a valid node
+        # Link the previous end of chain to the new free slot
+        # We re-fetch the node at 'cur' to be safe
         if (tail_node := self._table[cur]) is not None:
             tail_node.next = free
-
         self._len += 1
 
     def __getitem__(self, key: KEY) -> VAL:
@@ -118,7 +118,6 @@ def __getitem__(self, key: KEY) -> VAL:
             node = self._table[cur]
             if node is None:
                 break
-            assert node is not None
             if node.key == key:
                 return node.val
             cur = node.next
@@ -133,7 +132,6 @@ def __delitem__(self, key: KEY) -> None:
             node = self._table[cur]
             if node is None:
                 break
-            assert node is not None
             if node.key == key:
                 # If deleting head: copy next node into home if exists
                 #  (keeps chains valid).
@@ -142,17 +140,17 @@ def __delitem__(self, key: KEY) -> None:
                         self._table[cur] = None
                     else:
                         nxt = node.next
-                        # Safely copy next node data
-                        nxt_node = self._table[nxt]
-                        # Mypy needs to know nxt_node exists if we are copying from it
-                        if nxt_node is not None:
+                        next_node = self._table[nxt]
+                        # Must assert next_node is not None for mypy
+                        if next_node is not None:
                             self._table[cur] = _Node(
-                                nxt_node.key,
-                                nxt_node.val,
-                                nxt_node.next,
+                                next_node.key,
+                                next_node.val,
+                                next_node.next,
                             )
                             self._table[nxt] = None
                 else:
+                    # Update previous node's next pointer
                     prev_node = self._table[prev]
                     if prev_node is not None:
                         prev_node.next = node.next

data_structures/hashing/fnv_hashtable.py

@@ -10,7 +10,7 @@
 
 from collections.abc import Iterator, MutableMapping
 from dataclasses import dataclass
-from typing import TypeVar
+from typing import Generic, TypeVar
 
 KEY = TypeVar("KEY")
 VAL = TypeVar("VAL")
@@ -47,7 +47,7 @@ def fnv1a_64(data: bytes) -> int:
 
 
 @dataclass(slots=True)
-class _Item[KEY, VAL]:
+class _Item(Generic[KEY, VAL]):  # noqa: UP046
     key: KEY
     val: VAL
 

data_structures/hashing/hopscotch.py

@@ -11,14 +11,14 @@
 
 from collections.abc import Iterator, MutableMapping
 from dataclasses import dataclass
-from typing import TypeVar
+from typing import Generic, TypeVar
 
 KEY = TypeVar("KEY")
 VAL = TypeVar("VAL")
 
 
 @dataclass(slots=True)
-class _Item[KEY, VAL]:
+class _Item(Generic[KEY, VAL]):  # noqa: UP046
     key: KEY
     val: VAL
 

data_structures/hashing/linear_probing.py

@@ -16,7 +16,7 @@ class LinearProbing(HashTable):
     Hash function: h(k, i) = (h(k) + i) % m
     """
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
         super().__init__(*args, **kwargs)
 
     def _collision_resolution(self, key: int, data: Any = None) -> int | None:

data_structures/hashing/power_of_two.py

@@ -13,7 +13,7 @@
 
 from collections.abc import Iterator, MutableMapping
 from dataclasses import dataclass
-from typing import TypeVar
+from typing import Generic, TypeVar
 
 KEY = TypeVar("KEY")
 VAL = TypeVar("VAL")
@@ -38,7 +38,7 @@ def _mix_hash(h: int) -> int:
 
 
 @dataclass(slots=True)
-class _Item[KEY, VAL]:
+class _Item(Generic[KEY, VAL]):  # noqa: UP046
     key: KEY
     val: VAL
 

data_structures/hashing/robin_hood.py

@@ -9,14 +9,14 @@
 
 from collections.abc import Iterator, MutableMapping
 from dataclasses import dataclass
-from typing import TypeVar
+from typing import Generic, TypeVar
 
 KEY = TypeVar("KEY")
 VAL = TypeVar("VAL")
 
 
 @dataclass(slots=True)
-class _Entry[KEY, VAL]:
+class _Entry(Generic[KEY, VAL]):  # noqa: UP046
     key: KEY
     val: VAL
     psl: int  # probe sequence length (distance from home)