Include summary line

doc/usage/restructuredtext/directives.rst

@@ -1054,8 +1054,8 @@ Using collapsible content
       This is the body of the directive.
 
    Only the HTML 5 output format supports collapsible content. For other builders,
-   the body of the directive is rendered in the document and the *summary
-   description* text is ignored.
+   the *summary description* text and the body of the directive are rendered in
+   the document.
 
    .. versionadded:: 5.1
 

sphinx/directives/other.py

@@ -405,7 +405,7 @@ def run(self) -> List[Node]:
         if len(self.arguments) > 0:
             summary = self.arguments[0].strip()
         else:
-            summary = "Collapsed Content"
+            summary = "Collapsed Content:"
 
         # parse the argument as reST
         summary_trimmed = self._prepare_argument_string(summary)

sphinx/util/nodes.py

@@ -640,9 +640,9 @@ def process_collapsible_nodes(document: Node, builder_name: str) -> None:
             # result in a "Losing ids" exception if there is a target node before
             # the only node, so we make sure docutils can transfer the id to
             # something, even if it's just a comment and will lose the id anyway...
-            # Slicing node.children removes the first element, which will always
-            # be a collapsible_summary node.
-            node.replace_self(node.children[1:] or nodes.comment())
+            children = node.children
+            children[0] = nodes.paragraph("", "", *children[0].children)  # type: ignore
+            node.replace_self(children or nodes.comment())
 
 
 def _new_copy(self: Element) -> Element:

tests/roots/test-directive-collapsible/index.rst

@@ -5,7 +5,7 @@ Collapsible directive tests
 
    Default section summary line
 
-.. collapsible:: Custom summary line for the collapsible content
+.. collapsible:: Custom summary line for the collapsible content:
 
    Collapsible sections can also have custom summary lines
 

tests/test_directive_collapsible.py

@@ -15,13 +15,21 @@ def test_non_html(app, status, warning):
 Collapsible directive tests
 ***************************
 
+Collapsed Content:
+
 Default section summary line
 
+Custom summary line for the collapsible content:
+
 Collapsible sections can also have custom summary lines
 
+Collapsed Content:
+
 Collapsible sections can have normal reST content such as **bold** and
 *emphasised* text, and also links!
 
+Collapsed Content:
+
 Collapsible sections can have sections:
 
 
@@ -30,6 +38,10 @@ def test_non_html(app, status, warning):
 
 Some words within a section, as opposed to outwith the section.
 
+Summary text here with **bold** and *em* and a **RFC 2324** reference!
+That was a newline in the reST source! We can also have links and more
+links.
+
 This is some text!
 """
 
@@ -47,9 +59,9 @@ def test_html(app, status, warning):
     assert isinstance(collapsible_nodes[3][0], addnodes.collapsible_summary)
     assert isinstance(collapsible_nodes[4][0], addnodes.collapsible_summary)
 
-    assert collapsible_nodes[0][0].astext() == 'Collapsed Content'
-    assert collapsible_nodes[2][0].astext() == 'Collapsed Content'
-    assert collapsible_nodes[3][0].astext() == 'Collapsed Content'
+    assert collapsible_nodes[0][0].astext() == 'Collapsed Content:'
+    assert collapsible_nodes[2][0].astext() == 'Collapsed Content:'
+    assert collapsible_nodes[3][0].astext() == 'Collapsed Content:'
 
     assert isinstance(collapsible_nodes[3][2], nodes.section)