Fix IndexError when a module docstring contains only a heading

autoapi/directives.py

@@ -58,9 +58,10 @@ class NestedParse(Directive):
         node.document = self.state.document
         nested_parse_with_titles(self.state, self.content, node)
         try:
-            title_node = node[0][0]
-            if isinstance(title_node, nodes.title):
-                del node[0][0]
+            if isinstance(node[0], nodes.section) and isinstance(
+                node[0][0], nodes.title
+            ):
+                node.children = node[0][1:] + node.children[1:]
         except IndexError:
             pass
         return node.children

docs/changes/412.bugfix

@@ -0,0 +1 @@
+Fix IndexError when a module docstring contains only a heading

tests/python/pypackagecomplex/complex/__init__.py

@@ -1,3 +1,8 @@
+"""
+This heading will be removed
+============================
+"""
+
 from .subpackage import public_chain
 from .subpackage.submodule import public_multiple_imports
 

tests/python/pypackagecomplex/complex/subpackage/submodule.py

@@ -1,3 +1,11 @@
+"""
+This heading will be removed
+============================
+
+This docstring will not be removed.
+"""
+
+
 def public_chain():
     """Part of a public resolution chain."""
     return 5

tests/python/test_pyintegration.py

@@ -1005,6 +1005,13 @@ class TestComplexPackage:
 
         assert foo_file.find(id="complex.unicode_data.unicode_str")
 
+    def test_nested_parse_directive(self, parse):
+        package_file = parse("_build/html/autoapi/complex/index.html")
+
+        complex = package_file.find(id="complex")
+        assert "This heading will be removed" not in complex.parent.text
+        assert complex.parent.find("section")["id"] != "this-heading-will-be-removed"
+
 
 class TestComplexPackageParallel(TestComplexPackage):
     @pytest.fixture(autouse=True, scope="class")