Keep usefixtures fixtures ahead of autouse dependencies

changelog/14992.bugfix.rst

@@ -0,0 +1 @@
+Fixed fixture setup order so fixtures requested by ``usefixtures`` remain ahead of dependencies of earlier autouse fixtures.

src/_pytest/fixtures.py

@@ -1985,14 +1985,18 @@ def sort_by_scope(arg_name: str) -> Scope:
             else:
                 return fixturedefs[-1]._scope
 
-        fixturenames_closure = sorted(
-            traverse_fixture_closure(
+        # Keep the initial fixtures at the front of the closure. Their order
+        # is observable by hooks such as pytest_generate_tests.
+        fixturenames_closure = list(initialnames)
+        fixturenames_closure.extend(
+            argname
+            for argname in traverse_fixture_closure(
                 initialnames,
                 getfixturedefs=getfixturedefs,
-            ),
-            key=sort_by_scope,
-            reverse=True,
+            )
+            if argname not in initialnames
         )
+        fixturenames_closure.sort(key=sort_by_scope, reverse=True)
 
         return fixturenames_closure, arg2fixturedefs
 

testing/example_scripts/fixtures/test_getfixturevalue_dynamic.py

@@ -20,4 +20,4 @@ def b(a):
 
 
 def test(b, request):
-    assert request.fixturenames == ["b", "a", "request", "dynamic"]
+    assert request.fixturenames == ["b", "request", "a", "dynamic"]

testing/python/fixtures.py

@@ -2529,6 +2529,49 @@ def test_hello(arg1):
         reprec = pytester.inline_run()
         reprec.assertoutcome(passed=1)
 
+    def test_usefixtures_before_autouse_dependencies(self, pytester: Pytester) -> None:
+        pytester.makepyfile(
+            """
+            import pytest
+
+            order = []
+
+            @pytest.fixture
+            def precondition():
+                order.append("precondition")
+
+            @pytest.fixture
+            def subject_deps(precondition):
+                order.append("subject_deps")
+
+            @pytest.fixture(autouse=True)
+            def subject(subject_deps):
+                order.append("subject")
+
+            @pytest.fixture
+            def guard():
+                order.append("guard")
+
+            def pytest_generate_tests(metafunc):
+                names = metafunc.fixturenames
+                if "subject" in names:
+                    names.remove("subject")
+                    names.append("subject")
+
+            @pytest.mark.usefixtures("guard")
+            class TestOrdering:
+                def test_guard_is_set_up_first(self):
+                    assert order == [
+                        "guard",
+                        "precondition",
+                        "subject_deps",
+                        "subject",
+                    ]
+        """
+        )
+        result = pytester.runpytest()
+        result.assert_outcomes(passed=1)
+
     @pytest.mark.parametrize("param1", ["", "params=[1]"], ids=["p00", "p01"])
     @pytest.mark.parametrize("param2", ["", "params=[1]"], ids=["p10", "p11"])
     def test_ordering_dependencies_torndown_first(
@@ -4673,8 +4716,8 @@ def test_foo(f1, p1, m1, f2, s1):
                 # Actual fixture execution differs from static order: dependent
                 # fixtures must be created first ("my_tmp_path").
                 assert fixture_order == [
-                    "my_tmp_path_factory",
                     "s1",
+                    "my_tmp_path_factory",
                     "p1",
                     "m1",
                     "my_tmp_path",
@@ -4689,13 +4732,13 @@ def test_foo(f1, p1, m1, f2, s1):
         # Static order of fixtures based on their scope and position in the
         # parameter list.
         assert request.fixturenames == [
-            "my_tmp_path_factory",
             "s1",
+            "my_tmp_path_factory",
             "p1",
             "m1",
             "f1",
-            "my_tmp_path",
             "f2",
+            "my_tmp_path",
         ]
         result = pytester.runpytest("-vv")
         result.assert_outcomes(passed=1)
@@ -5871,7 +5914,7 @@ def test_circular_deps(fix_a, fix_x):
     )
     items, _hookrec = pytester.inline_genitems()
     assert isinstance(items[0], Function)
-    assert items[0].fixturenames == ["fix_a", "fix_b", "fix_x", "fix_y", "fix_z"]
+    assert items[0].fixturenames == ["fix_a", "fix_x", "fix_b", "fix_y", "fix_z"]
 
 
 def test_fixture_closure_handles_diamond_dependencies(pytester: Pytester) -> None: