BUG: Correct dummy decorator

arch/compat/numba.py

@@ -27,8 +27,17 @@ def jit(
         **kwargs: Any,
     ) -> Any:
         if function_or_signature is not None and callable(function_or_signature):
-            return function_or_signature
+            # Used directly, e.g., f_jit = jit(f)
+            @functools.wraps(function_or_signature)
+            def wrapper(*args: Any, **kwargs: Any) -> Callable[..., Any]:
+                import warnings
+
+                warnings.warn(performance_warning, PerformanceWarning)
+                return function_or_signature(*args, **kwargs)
+
+            return wrapper
 
+        # Used as a decorator, e.g., @jit
         def wrap(func):
             @functools.wraps(func)
             def wrapper(*args: Any, **kwargs: Any) -> Callable[..., Any]:

arch/tests/univariate/test_recursions.py

@@ -13,6 +13,7 @@
 from arch.univariate.volatility import RiskMetrics2006
 
 CYTHON_COVERAGE = os.environ.get("ARCH_CYTHON_COVERAGE", "0") in ("true", "1", "True")
+DISABLE_NUMBA = os.environ.get("ARCH_DISABLE_NUMBA", False) in ("1", "true", "True")
 
 try:
     import arch.univariate.recursions as rec_cython
@@ -29,7 +30,7 @@
 try:
     import numba  # noqa
 
-    MISSING_NUMBA = False
+    MISSING_NUMBA = False or DISABLE_NUMBA
 except ImportError:
     MISSING_NUMBA = True
 

arch/univariate/base.py

@@ -1189,10 +1189,7 @@ def summary(self) -> Summary:
 
         stubs = list(self._names)
         header = ["coef"]
-        param_table_data = [
-            [format_float_fixed(param, 10, 4)]
-            for param in self.params
-        ]
+        param_table_data = [[format_float_fixed(param, 10, 4)] for param in self.params]
 
         mc = self.model.num_params
         vc = self.model.volatility.num_params