Merge pull request #13458 from pytest-dev/dup-param-error

python: a bit nicer error on duplicate parametrization

Author: bluetech

changelog/13457.improvement.rst

@@ -0,0 +1 @@
+The error message about duplicate parametrization no longer displays an internal stack trace.

src/_pytest/python.py

@@ -1073,13 +1073,16 @@ def setmulti(
         marks: Iterable[Mark | MarkDecorator],
         scope: Scope,
         param_index: int,
+        nodeid: str,
     ) -> CallSpec2:
         params = self.params.copy()
         indices = self.indices.copy()
         arg2scope = dict(self._arg2scope)
         for arg, val in zip(argnames, valset):
             if arg in params:
-                raise ValueError(f"duplicate parametrization of {arg!r}")
+                raise nodes.Collector.CollectError(
+                    f"{nodeid}: duplicate parametrization of {arg!r}"
+                )
             params[arg] = val
             indices[arg] = param_index
             arg2scope[arg] = scope
@@ -1233,6 +1236,8 @@ def parametrize(
             It will also override any fixture-function defined scope, allowing
             to set a dynamic scope using test context or configuration.
         """
+        nodeid = self.definition.nodeid
+
         argnames, parametersets = ParameterSet._for_parametrize(
             argnames,
             argvalues,
@@ -1244,7 +1249,7 @@ def parametrize(
 
         if "request" in argnames:
             fail(
-                "'request' is a reserved name and cannot be used in @pytest.mark.parametrize",
+                f"{nodeid}: 'request' is a reserved name and cannot be used in @pytest.mark.parametrize",
                 pytrace=False,
             )
 
@@ -1339,6 +1344,7 @@ def parametrize(
                     marks=param_set.marks,
                     scope=scope_,
                     param_index=param_index,
+                    nodeid=nodeid,
                 )
                 newcalls.append(newcallspec)
         self._calls = newcalls

testing/python/metafunc.py

@@ -82,11 +82,15 @@ def func(x, y):
 
         metafunc = self.Metafunc(func)
         metafunc.parametrize("x", [1, 2])
-        pytest.raises(ValueError, lambda: metafunc.parametrize("x", [5, 6]))
-        pytest.raises(ValueError, lambda: metafunc.parametrize("x", [5, 6]))
+        with pytest.raises(pytest.Collector.CollectError):
+            metafunc.parametrize("x", [5, 6])
+        with pytest.raises(pytest.Collector.CollectError):
+            metafunc.parametrize("x", [5, 6])
         metafunc.parametrize("y", [1, 2])
-        pytest.raises(ValueError, lambda: metafunc.parametrize("y", [5, 6]))
-        pytest.raises(ValueError, lambda: metafunc.parametrize("y", [5, 6]))
+        with pytest.raises(pytest.Collector.CollectError):
+            metafunc.parametrize("y", [5, 6])
+        with pytest.raises(pytest.Collector.CollectError):
+            metafunc.parametrize("y", [5, 6])
 
         with pytest.raises(TypeError, match="^ids must be a callable or an iterable$"):
             metafunc.parametrize("y", [5, 6], ids=42)  # type: ignore[arg-type]