Use a proxy type for JSON schema

Author: alexreinking

src/scikit_build_core/resources/scikit-build.schema.json

@@ -37,6 +37,12 @@
                     },
                     {
                       "type": "boolean"
+                    },
+                    {
+                      "type": "array",
+                      "items": {
+                        "type": "string"
+                      }
                     }
                   ]
                 },
@@ -58,6 +64,12 @@
                         },
                         {
                           "type": "boolean"
+                        },
+                        {
+                          "type": "array",
+                          "items": {
+                            "type": "string"
+                          }
                         }
                       ]
                     }

src/scikit_build_core/settings/json_schema.py

@@ -151,6 +151,8 @@ def convert_type(t: Any, *, normalize_keys: bool) -> dict[str, Any]:
         }
     if origin is Literal:
         return {"enum": list(args)}
+    if hasattr(t, "json_schema"):
+        return convert_type(t.json_schema, normalize_keys=normalize_keys)
 
     msg = f"Cannot convert type {t} to JSON Schema"
     raise FailedConversionError(msg)

src/scikit_build_core/settings/skbuild_model.py

@@ -28,6 +28,8 @@ def __dir__() -> List[str]:
 
 
 class CMakeSettingsDefine(str):
+    json_schema = Union[str, bool, List[str]]
+
     def __new__(cls, raw: Union[str, bool, List[str]]) -> "CMakeSettingsDefine":
         def escape_semicolons(item: str) -> str:
             return item.replace(";", r"\;")