[WIP][RFC][NOMERGE] Node nomore smart init

src/_pytest/compat.py

@@ -308,7 +308,6 @@ def safe_isclass(obj):
     "Collector",
     "Module",
     "Function",
-    "Instance",
     "Session",
     "Item",
     "Class",

src/_pytest/fixtures.py

@@ -64,8 +64,7 @@ def pytest_sessionstart(session):
 scope2props["package"] = ("fspath",)
 scope2props["module"] = ("fspath", "module")
 scope2props["class"] = scope2props["module"] + ("cls",)
-scope2props["instance"] = scope2props["class"] + ("instance",)
-scope2props["function"] = scope2props["instance"] + ("function", "keywords")
+scope2props["function"] = scope2props["class"] + ("function", "keywords")
 
 
 def scopeproperty(name=None, doc=None):
@@ -399,16 +398,6 @@ def cls(self):
         if clscol:
             return clscol.obj
 
-    @property
-    def instance(self):
-        """ instance (can be None) on which test function was collected. """
-        # unittest support hack, see _pytest.unittest.TestCaseFunction
-        try:
-            return self._pyfuncitem._testcase
-        except AttributeError:
-            function = getattr(self, "function", None)
-            return getattr(function, "__self__", None)
-
     @scopeproperty()
     def module(self):
         """ python module object where the test function was collected. """

src/_pytest/mark/legacy.py

@@ -37,12 +37,8 @@ def __init__(self, names):
     def from_item(cls, item):
         mapped_names = set()
 
-        # Add the names of the current item and any parent items
-        import pytest
-
         for item in item.listchain():
-            if not isinstance(item, pytest.Instance):
-                mapped_names.add(item.name)
+            mapped_names.add(item.name)
 
         # Add the names added as extra keywords to current or parent items
         mapped_names.update(item.listextrakeywords())

src/_pytest/nodes.py

@@ -102,9 +102,7 @@ def __init__(
             assert "::()" not in nodeid
             self._nodeid = nodeid
         else:
-            self._nodeid = self.parent.nodeid
-            if self.name != "()":
-                self._nodeid += "::" + self.name
+            self._nodeid = self.parent.nodeid + "::" + self.name
 
     @property
     def ihook(self):

src/_pytest/python.py

@@ -167,6 +167,9 @@ def async_warn():
         async_warn()
     funcargs = pyfuncitem.funcargs
     testargs = {arg: funcargs[arg] for arg in pyfuncitem._fixtureinfo.argnames}
+    if isinstance(pyfuncitem.parent, Class):
+        inst = pyfuncitem.parent.obj()
+        testfunction = testfunction.__get__(inst, type(inst))
     result = testfunction(**testargs)
     if hasattr(result, "__await__") or hasattr(result, "__aiter__"):
         async_warn()
@@ -242,7 +245,6 @@ def pytest_make_parametrize_id(config, val, argname=None):
 class PyobjContext:
     module = pyobj_property("Module")
     cls = pyobj_property("Class")
-    instance = pyobj_property("Instance")
 
 
 class PyobjMixin(PyobjContext):
@@ -256,8 +258,7 @@ def obj(self):
             self._obj = obj = self._getobj()
             # XXX evil hack
             # used to avoid Instance collector marker duplication
-            if self._ALLOW_MARKERS:
-                self.own_markers.extend(get_unpacked_marks(self.obj))
+            self.own_markers.extend(get_unpacked_marks(self.obj))
         return obj
 
     @obj.setter
@@ -274,8 +275,6 @@ def getmodpath(self, stopatmodule=True, includemodule=False):
         chain.reverse()
         parts = []
         for node in chain:
-            if isinstance(node, Instance):
-                continue
             name = node.name
             if isinstance(node, Module):
                 name = os.path.splitext(name)[0]
@@ -709,7 +708,7 @@ def collect(self):
         self._inject_setup_class_fixture()
         self._inject_setup_method_fixture()
 
-        return [Instance(name="()", parent=self)]
+        return super().collect()
 
     def _inject_setup_class_fixture(self):
         """Injects a hidden autouse, class scoped fixture into the collected class object
@@ -761,33 +760,13 @@ def xunit_setup_method_fixture(self, request):
         self.obj.__pytest_setup_method = xunit_setup_method_fixture
 
 
-class Instance(PyCollector):
-    _ALLOW_MARKERS = False  # hack, destroy later
-    # instances share the object with their parents in a way
-    # that duplicates markers instances if not taken out
-    # can be removed at node structure reorganization time
-
-    def _getobj(self):
-        return self.parent.obj()
-
-    def collect(self):
-        self.session._fixturemanager.parsefactories(self)
-        return super().collect()
-
-    def newinstance(self):
-        self.obj = self._getobj()
-        return self.obj
-
-
 class FunctionMixin(PyobjMixin):
     """ mixin for the code common to Function and Generator.
     """
 
     def setup(self):
         """ perform setup for this test function. """
-        if isinstance(self.parent, Instance):
-            self.parent.newinstance()
-            self.obj = self._getobj()
+        self.obj = self._getobj()
 
     def _prunetraceback(self, excinfo):
         if hasattr(self, "_obj") and not self.config.getoption("fulltrace", False):

src/pytest.py

@@ -28,7 +28,6 @@
 from _pytest.outcomes import xfail
 from _pytest.python import Class
 from _pytest.python import Function
-from _pytest.python import Instance
 from _pytest.python import Module
 from _pytest.python import Package
 from _pytest.python_api import approx
@@ -66,7 +65,6 @@
     "hookimpl",
     "hookspec",
     "importorskip",
-    "Instance",
     "Item",
     "main",
     "mark",