feat(config): add explicit validation for required configuration fields (#2078)

* feat(config): add explicit validation for required configuration fields

* feat(config): add explicit validation for required configuration fields

* fix(config): always validate configuration regardless of registration

* config: clarify validation semantics and document future migration plan

* fix: pylint error

---------

Co-authored-by: Linlang <Lv.Linlang@hotmail.com>

Author: Sourish-07

qlib/config.py

@@ -63,16 +63,33 @@ class QSettings(BaseSettings):
 
 class Config:
     def __init__(self, default_conf):
-        self.__dict__["_default_config"] = copy.deepcopy(default_conf)  # avoiding conflicts with __getattr__
+        self.__dict__["_default_config"] = copy.deepcopy(default_conf)
         self.reset()
 
+    # TODO: This validation logic is a temporary solution.
+    # The long-term goal is to migrate Qlib Config to a typed configuration
+    # system based on pydantic.BaseModel, with explicit schema and field validation.
+    def validate(self):
+        errors = []
+
+        if not self.get("provider_uri"):
+            errors.append("provider_uri must be set (e.g. ~/.qlib/qlib_data or a valid path)")
+
+        if not self.get("region"):
+            errors.append("region must be specified (e.g. 'cn', 'us')")
+
+        if errors:
+            raise ValueError(
+                "Invalid Qlib configuration (note: the global config has already been updated):\n"
+                "Invalid Qlib configuration:\n- " + "\n- ".join(errors)
+            )
+
     def __getitem__(self, key):
         return self.__dict__["_config"][key]
 
     def __getattr__(self, attr):
         if attr in self.__dict__["_config"]:
             return self.__dict__["_config"][attr]
-
         raise AttributeError(f"No such `{attr}` in self._config")
 
     def get(self, key, default=None):
@@ -116,8 +133,11 @@ def register_from_C(config, skip_register=True):
             return
 
         C.set_conf_from_C(config)
+        C.validate()
+
         if C.logging_config:
             set_log_with_config(C.logging_config)
+
         C.register()
 
 

qlib/tests/test_config_validation.py

@@ -0,0 +1,17 @@
+import pytest
+
+from qlib.config import Config
+
+
+def test_missing_provider_uri_raises():
+    default_conf = {
+        "provider_uri": None,
+        "region": "us",
+    }
+
+    cfg = Config(default_conf)
+
+    with pytest.raises(ValueError) as exc:
+        cfg.validate()
+
+    assert "provider_uri must be set" in str(exc.value)