Remove prune_dependency_tree and reuse getfixtureclosure logic

Author: sadra-barikbin

src/_pytest/fixtures.py

@@ -337,33 +337,6 @@ class FuncFixtureInfo:
     # sequence is ordered from furthest to closes to the function.
     name2fixturedefs: dict[str, Sequence[FixtureDef[Any]]]
 
-    def prune_dependency_tree(self) -> None:
-        """Recompute names_closure from initialnames and name2fixturedefs.
-
-        Can only reduce names_closure, which means that the new closure will
-        always be a subset of the old one. The order is preserved.
-
-        This method is needed because direct parametrization may shadow some
-        of the fixtures that were included in the originally built dependency
-        tree. In this way the dependency tree can get pruned, and the closure
-        of argnames may get reduced.
-        """
-        closure: set[str] = set()
-        working_set = set(self.initialnames)
-        while working_set:
-            argname = working_set.pop()
-            # Argname may be something not included in the original names_closure,
-            # in which case we ignore it. This currently happens with pseudo
-            # FixtureDefs which wrap 'get_direct_param_fixture_func(request)'.
-            # So they introduce the new dependency 'request' which might have
-            # been missing in the original tree (closure).
-            if argname not in closure and argname in self.names_closure:
-                closure.add(argname)
-                if argname in self.name2fixturedefs:
-                    working_set.update(self.name2fixturedefs[argname][-1].argnames)
-
-        self.names_closure[:] = sorted(closure, key=self.names_closure.index)
-
 
 class FixtureRequest(abc.ABC):
     """The type of the ``request`` fixture.
@@ -968,7 +941,6 @@ def _eval_scope_callable(
     return result
 
 
-@final
 class FixtureDef(Generic[FixtureValue]):
     """A container for a fixture definition.
 
@@ -1136,6 +1108,26 @@ def __repr__(self) -> str:
         return f"<FixtureDef argname={self.argname!r} scope={self.scope!r} baseid={self.baseid!r}>"
 
 
+class IdentityFixtureDef(FixtureDef[FixtureValue]):
+    def __init__(
+        self,
+        config: Config,
+        argname: str,
+        scope: Scope | _ScopeName | Callable[[str, Config], _ScopeName] | None,
+        *,
+        _ispytest: bool = False,
+    ):
+        super().__init__(
+            config,
+            "",
+            argname,
+            lambda request: request.param,
+            scope,
+            None,
+            _ispytest=_ispytest,
+        )
+
+
 def resolve_fixture_function(
     fixturedef: FixtureDef[FixtureValue], request: FixtureRequest
 ) -> _FixtureFunc[FixtureValue]:
@@ -1567,10 +1559,11 @@ def getfixtureinfo(
         initialnames = deduplicate_names(autousenames, usefixturesnames, argnames)
 
         direct_parametrize_args = _get_direct_parametrize_args(node)
-
-        names_closure, arg2fixturedefs = self.getfixtureclosure(
+        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]] = {}
+        names_closure = self.getfixtureclosure(
             parentnode=node,
             initialnames=initialnames,
+            arg2fixturedefs=arg2fixturedefs,
             ignore_args=direct_parametrize_args,
         )
 
@@ -1622,30 +1615,32 @@ def getfixtureclosure(
         self,
         parentnode: nodes.Node,
         initialnames: tuple[str, ...],
+        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]],
         ignore_args: AbstractSet[str],
-    ) -> tuple[list[str], dict[str, Sequence[FixtureDef[Any]]]]:
+    ) -> list[str]:
         # Collect the closure of all fixtures, starting with the given
-        # fixturenames as the initial set.  As we have to visit all
-        # factory definitions anyway, we also return an arg2fixturedefs
-        # mapping so that the caller can reuse it and does not have
-        # to re-discover fixturedefs again for each fixturename
+        # initialnames containing function arguments, `usefixture` markers
+        # and `autouse` fixtures as the initial set.  As we have to visit all
+        # factory definitions anyway, we also populate arg2fixturedefs mapping
+        # for the args missing therein so that the caller can reuse it and does
+        # not have to re-discover fixturedefs again for each fixturename
         # (discovering matching fixtures for a given name/node is expensive).
 
         fixturenames_closure = list(initialnames)
 
-        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]] = {}
         lastlen = -1
         while lastlen != len(fixturenames_closure):
             lastlen = len(fixturenames_closure)
             for argname in fixturenames_closure:
                 if argname in ignore_args:
                     continue
-                if argname in arg2fixturedefs:
-                    continue
-                fixturedefs = self.getfixturedefs(argname, parentnode)
-                if fixturedefs:
-                    arg2fixturedefs[argname] = fixturedefs
-
+                if argname not in arg2fixturedefs:
+                    fixturedefs = self.getfixturedefs(argname, parentnode)
+                    if fixturedefs:
+                        arg2fixturedefs[argname] = fixturedefs
+                else:
+                    fixturedefs = arg2fixturedefs[argname]
+                if fixturedefs and not isinstance(fixturedefs[-1], IdentityFixtureDef):
                     # Add dependencies from this fixture.
                     # If it overrides a fixture with the same name and requests
                     # it, also add dependencies from the overridden fixtures in
@@ -1667,7 +1662,7 @@ def sort_by_scope(arg_name: str) -> Scope:
                 return fixturedefs[-1]._scope
 
         fixturenames_closure.sort(key=sort_by_scope, reverse=True)
-        return fixturenames_closure, arg2fixturedefs
+        return fixturenames_closure
 
     def pytest_generate_tests(self, metafunc: Metafunc) -> None:
         """Generate new tests based on parametrized fixtures used by the given metafunc"""

src/_pytest/python.py

@@ -51,10 +51,10 @@
 from _pytest.config import hookimpl
 from _pytest.config.argparsing import Parser
 from _pytest.deprecated import check_ispytest
-from _pytest.fixtures import FixtureDef
-from _pytest.fixtures import FixtureRequest
+from _pytest.fixtures import _get_direct_parametrize_args
 from _pytest.fixtures import FuncFixtureInfo
 from _pytest.fixtures import get_scope_node
+from _pytest.fixtures import IdentityFixtureDef
 from _pytest.main import Session
 from _pytest.mark import ParameterSet
 from _pytest.mark.structures import _HiddenParam
@@ -448,8 +448,6 @@ def _genfunctions(self, name: str, funcobj) -> Iterator[Function]:
         definition = FunctionDefinition.from_parent(self, name=name, callobj=funcobj)
         fixtureinfo = definition._fixtureinfo
 
-        # pytest_generate_tests impls call metafunc.parametrize() which fills
-        # metafunc._calls, the outcome of the hook.
         metafunc = Metafunc(
             definition=definition,
             fixtureinfo=fixtureinfo,
@@ -458,24 +456,34 @@ def _genfunctions(self, name: str, funcobj) -> Iterator[Function]:
             module=module,
             _ispytest=True,
         )
-        methods = []
+
+        def prune_dependency_tree_if_test_is_directly_parametrized(
+            metafunc: Metafunc,
+        ) -> None:
+            # Direct (those with `indirect=False`) parametrizations taking place in
+            # module/class-specific `pytest_generate_tests` hooks, a.k.a dynamic direct
+            # parametrizations using `metafunc.parametrize`, may have shadowed some
+            # fixtures, making some fixtures no longer reachable. Update the dependency
+            # tree to reflect what the item really needs.
+            # Note that direct parametrizations using `@pytest.mark.parametrize` have
+            # already been considered into making the closure using the `ignore_args`
+            # arg to `getfixtureclosure`.
+            if metafunc._has_direct_parametrization:
+                metafunc._update_dependency_tree()
+
+        methods = [prune_dependency_tree_if_test_is_directly_parametrized]
         if hasattr(module, "pytest_generate_tests"):
             methods.append(module.pytest_generate_tests)
         if cls is not None and hasattr(cls, "pytest_generate_tests"):
             methods.append(cls().pytest_generate_tests)
+
+        # pytest_generate_tests impls call metafunc.parametrize() which fills
+        # metafunc._calls, the outcome of the hook.
         self.ihook.pytest_generate_tests.call_extra(methods, dict(metafunc=metafunc))
 
         if not metafunc._calls:
             yield Function.from_parent(self, name=name, fixtureinfo=fixtureinfo)
         else:
-            metafunc._recompute_direct_params_indices()
-            # Direct parametrizations taking place in module/class-specific
-            # `metafunc.parametrize` calls may have shadowed some fixtures, so make sure
-            # we update what the function really needs a.k.a its fixture closure. Note that
-            # direct parametrizations using `@pytest.mark.parametrize` have already been considered
-            # into making the closure using `ignore_args` arg to `getfixtureclosure`.
-            fixtureinfo.prune_dependency_tree()
-
             for callspec in metafunc._calls:
                 subname = f"{name}[{callspec.id}]" if callspec._idlist else name
                 yield Function.from_parent(
@@ -1108,12 +1116,8 @@ def id(self) -> str:
         return "-".join(self._idlist)
 
 
-def get_direct_param_fixture_func(request: FixtureRequest) -> Any:
-    return request.param
-
-
 # Used for storing pseudo fixturedefs for direct parametrization.
-name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any]]]()
+name2pseudofixturedef_key = StashKey[dict[str, IdentityFixtureDef[Any]]]()
 
 
 @final
@@ -1162,6 +1166,9 @@ def __init__(
 
         self._params_directness: dict[str, Literal["indirect", "direct"]] = {}
 
+        # Whether it's ever been directly parametrized, i.e. with `indirect=False`.
+        self._has_direct_parametrization = False
+
     def parametrize(
         self,
         argnames: str | Sequence[str],
@@ -1308,24 +1315,21 @@ def parametrize(
                     node = collector.session
                 else:
                     assert False, f"Unhandled missing scope: {scope}"
-            default: dict[str, FixtureDef[Any]] = {}
+            default: dict[str, IdentityFixtureDef[Any]] = {}
             name2pseudofixturedef = node.stash.setdefault(
                 name2pseudofixturedef_key, default
             )
         for argname in argnames:
             if arg_directness[argname] == "indirect":
                 continue
+            self._has_direct_parametrization = True
             if name2pseudofixturedef is not None and argname in name2pseudofixturedef:
                 fixturedef = name2pseudofixturedef[argname]
             else:
-                fixturedef = FixtureDef(
-                    config=self.config,
-                    baseid="",
+                fixturedef = IdentityFixtureDef(
+                    config=self.definition.config,
                     argname=argname,
-                    func=get_direct_param_fixture_func,
                     scope=scope_,
-                    params=None,
-                    ids=None,
                     _ispytest=True,
                 )
                 if name2pseudofixturedef is not None:
@@ -1485,11 +1489,17 @@ def _validate_if_using_arg_names(
                         pytrace=False,
                     )
 
-    def _recompute_direct_params_indices(self) -> None:
-        for argname, param_type in self._params_directness.items():
-            if param_type == "direct":
-                for i, callspec in enumerate(self._calls):
-                    callspec.indices[argname] = i
+    def _update_dependency_tree(self) -> None:
+        definition = self.definition
+        assert definition.parent is not None
+        fm = definition.parent.session._fixturemanager
+        fixture_closure = fm.getfixtureclosure(
+            parentnode=definition,
+            initialnames=definition._fixtureinfo.initialnames,
+            arg2fixturedefs=definition._fixtureinfo.name2fixturedefs,
+            ignore_args=_get_direct_parametrize_args(definition),
+        )
+        definition._fixtureinfo.names_closure[:] = fixture_closure
 
 
 def _find_parametrized_scope(