Merge pull request #1 from untitaker/feat/exact-length-lists

Treat heterogenous lists of exact length as tuples

jsonschema_typed/plugin.py

@@ -274,6 +274,14 @@ def array(
             inner_types = [AnyType(TypeOfAny.unannotated)]
         elif items is False:
             raise NotImplementedError('"items": false is not supported')
+        elif isinstance(items, list):
+            # https://json-schema.org/understanding-json-schema/reference/array.html#tuple-validation
+            if {schema.get("minItems"), schema.get("maxItems")} - {None, len(items)}:
+                raise NotImplementedError(
+                    '"items": If list, must have minItems == maxItems'
+                )
+            inner_types = [self.get_type(ctx, item) for item in items]
+            return ctx.api.tuple_type(inner_types)
         elif items is not None:
             inner_types = [self.get_type(ctx, items)]
         else:

schema/tuple.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "$id": "http://foo.qwerty/some/schema#",
+  "title": "List of tuples",
+  "type": "array",
+  "items": {
+    "type": [
+      "array",
+      "null"
+    ],
+    "items": [
+      {
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      {
+        "type": [
+          "string",
+          "null"
+        ]
+      }
+    ],
+    "maxItems": 2,
+    "minItems": 2
+  }
+}

tests/cases/tuple.py

@@ -0,0 +1,15 @@
+from jsonschema_typed import JSONSchema
+from typing import TYPE_CHECKING
+
+
+Ty = JSONSchema["schema/tuple.json"]
+
+data: Ty = [("key", "value")]
+
+error0: Ty = [["key", "value"]]
+error1: Ty = [("key", "value", "toomuch")]
+error2: Ty = [1]
+error3: Ty = [(1, 2)]
+
+if TYPE_CHECKING:
+    reveal_type(data)

tests/test_run_mypy.py

@@ -132,6 +132,21 @@ class Expect(TypedDict):
             exit_status=1,
         ),
     ),
+    (
+        "tuple.py",
+        Expect(
+            normal="""
+            tests/cases/tuple.py:9: error: List item 0 has incompatible type "List[str]"; expected "Optional[Tuple[Optional[str], Optional[str]]]"
+            tests/cases/tuple.py:10: error: List item 0 has incompatible type "Tuple[str, str, str]"; expected "Optional[Tuple[Optional[str], Optional[str]]]"
+            tests/cases/tuple.py:11: error: List item 0 has incompatible type "int"; expected "Optional[Tuple[Optional[str], Optional[str]]]"
+            tests/cases/tuple.py:12: error: List item 0 has incompatible type "Tuple[int, int]"; expected "Optional[Tuple[Optional[str], Optional[str]]]"
+            tests/cases/tuple.py:15: note: Revealed type is 'builtins.list[Union[Tuple[Union[builtins.str, None], Union[builtins.str, None]], None]]'
+            Found 4 errors in 1 file (checked 1 source file)
+            """,
+            error="",
+            exit_status=1,
+        ),
+    ),
 ]