feat(config): allow value decoding with only the type info

ruyi/config/errors.py

@@ -48,15 +48,17 @@ def __repr__(self) -> str:
 class InvalidConfigValueError(ValueError):
     def __init__(
         self,
-        key: str | Sequence[str],
+        key: str | Sequence[str] | type,
         val: object | None,
     ) -> None:
         super().__init__()
         self._key = key
         self._val = val
 
     def __str__(self) -> str:
-        return f"invalid value for config key {self._key}: {self._val}"
+        if isinstance(self._key, type):
+            return f"invalid config value for type {self._key}: {self._val}"
+        return f"invalid config value for key {self._key}: {self._val}"
 
     def __repr__(self) -> str:
         return f"InvalidConfigValueError({self._key:!r}, {self._val:!r})"

ruyi/config/schema.py

@@ -159,13 +159,17 @@ def encode_value(v: object) -> str:
 
 
 def decode_value(
-    key: str | Sequence[str],
+    key: str | Sequence[str] | type,
     val: str,
 ) -> object:
     """Decodes the given string representation of a config value into a Python
     value, directed by type information implied by the config key."""
 
-    expected_type = get_expected_type_for_config_key(key)
+    if isinstance(key, type):
+        expected_type = key
+    else:
+        expected_type = get_expected_type_for_config_key(key)
+
     if expected_type is bool:
         if val in ("true", "yes", "1"):
             return True

tests/config/test_schema.py

@@ -8,31 +8,35 @@
 
 def test_decode_value_bool() -> None:
     assert decode_value("installation.externally_managed", "true") is True
-    assert decode_value("installation.externally_managed", "false") is False
-    assert decode_value("installation.externally_managed", "yes") is True
-    assert decode_value("installation.externally_managed", "no") is False
-    assert decode_value("installation.externally_managed", "1") is True
-    assert decode_value("installation.externally_managed", "0") is False
+
+    assert decode_value(bool, "true") is True
+    assert decode_value(bool, "false") is False
+    assert decode_value(bool, "yes") is True
+    assert decode_value(bool, "no") is False
+    assert decode_value(bool, "1") is True
+    assert decode_value(bool, "0") is False
     with pytest.raises(InvalidConfigValueError):
-        decode_value("installation.externally_managed", "invalid")
+        decode_value(bool, "invalid")
     with pytest.raises(InvalidConfigValueError):
-        decode_value("installation.externally_managed", "x")
+        decode_value(bool, "x")
     with pytest.raises(InvalidConfigValueError):
-        decode_value("installation.externally_managed", "True")
+        decode_value(bool, "True")
 
 
 def test_decode_value_str() -> None:
     assert decode_value("repo.branch", "main") == "main"
+    assert decode_value(str, "main") == "main"
 
 
 def test_decode_value_datetime() -> None:
     tz_aware_dt = datetime.datetime(2024, 12, 1, 12, 0, 0, tzinfo=datetime.timezone.utc)
     assert (
         decode_value("telemetry.upload_consent", "2024-12-01T12:00:00Z") == tz_aware_dt
     )
+    assert decode_value(datetime.datetime, "2024-12-01T12:00:00Z") == tz_aware_dt
 
     # naive datetimes are decoded using the implicit local timezone
-    decode_value("telemetry.upload_consent", "2024-12-01T12:00:00")
+    decode_value(datetime.datetime, "2024-12-01T12:00:00")
 
 
 def test_encode_value_bool() -> None: