fix: resolve doctest locations for fixture definitions

changelog/14700.bugfix.rst

@@ -0,0 +1 @@
+Fixed an internal error on Python 3.12 when a doctest on a fixture-decorated function was skipped.

src/_pytest/doctest.py

@@ -32,6 +32,7 @@
 from _pytest.config import Config
 from _pytest.config.argparsing import Parser
 from _pytest.fixtures import fixture
+from _pytest.fixtures import FixtureFunctionDefinition
 from _pytest.fixtures import TopRequest
 from _pytest.nodes import Collector
 from _pytest.nodes import Item
@@ -529,6 +530,17 @@ def _find_lineno(self, obj, source_lines):
                         obj,
                         source_lines,
                     )
+            elif py_ver_info_minor == (3, 12):
+
+                def _find_lineno(self, obj, source_lines):
+                    if isinstance(obj, FixtureFunctionDefinition):
+                        obj = inspect.unwrap(obj)
+
+                    # Type ignored because this is a private function.
+                    return super()._find_lineno(  # type:ignore[misc]
+                        obj,
+                        source_lines,
+                    )
 
             if sys.version_info < (3, 13):
 

testing/test_doctest.py

@@ -875,6 +875,29 @@ def foo(x):
         reportinfo = items[0].reportinfo()
         assert reportinfo[1] == 1
 
+    @pytest.mark.skipif(
+        sys.version_info < (3, 12), reason="requires Python 3.12 or later"
+    )
+    def test_fixture_doctest_skip_has_line_number(self, pytester: Pytester):
+        p = pytester.makepyfile(
+            test_fixture_doctest_skip="""
+            import pytest
+
+            @pytest.fixture
+            def unavailable():
+                '''
+                >>> getfixture("unavailable")
+                '''
+                pytest.skip("unavailable")
+            """
+        )
+        items, _reprec = pytester.inline_genitems(p, "--doctest-modules")
+        assert items[0].reportinfo()[1] is not None
+
+        result = pytester.runpytest(p, "--doctest-modules")
+        assert "INTERNALERROR" not in result.stdout.str()
+        result.assert_outcomes(skipped=1)
+
     def test_valid_setup_py(self, pytester: Pytester):
         """
         Test to make sure that pytest ignores valid setup.py files when ran