1 files changed, 61 insertions, 0 deletions
diff --git a/sphinx/environment/collectors/title.py b/sphinx/environment/collectors/title.py
new file mode 100644
index 0000000..014d77a
--- /dev/null
+++ b/sphinx/environment/collectors/title.py
@@ -0,0 +1,61 @@
+"""The title collector components for sphinx.environment."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+from docutils import nodes
+
+from sphinx.environment.collectors import EnvironmentCollector
+from sphinx.transforms import SphinxContentsFilter
+
+if TYPE_CHECKING:
+    from sphinx.application import Sphinx
+    from sphinx.environment import BuildEnvironment
+
+
+class TitleCollector(EnvironmentCollector):
+    """title collector for sphinx.environment."""
+
+    def clear_doc(self, app: Sphinx, env: BuildEnvironment, docname: str) -> None:
+        env.titles.pop(docname, None)
+        env.longtitles.pop(docname, None)
+
+    def merge_other(self, app: Sphinx, env: BuildEnvironment,
+                    docnames: set[str], other: BuildEnvironment) -> None:
+        for docname in docnames:
+            env.titles[docname] = other.titles[docname]
+            env.longtitles[docname] = other.longtitles[docname]
+
+    def process_doc(self, app: Sphinx, doctree: nodes.document) -> None:
+        """Add a title node to the document (just copy the first section title),
+        and store that title in the environment.
+        """
+        titlenode = nodes.title()
+        longtitlenode = titlenode
+        # explicit title set with title directive; use this only for
+        # the <title> tag in HTML output
+        if 'title' in doctree:
+            longtitlenode = nodes.title()
+            longtitlenode += nodes.Text(doctree['title'])
+        # look for first section title and use that as the title
+        for node in doctree.findall(nodes.section):
+            visitor = SphinxContentsFilter(doctree)
+            node[0].walkabout(visitor)
+            titlenode += visitor.get_entry_text()
+            break
+        else:
+            # document has no title
+            titlenode += nodes.Text(doctree.get('title', '<no title>'))
+        app.env.titles[app.env.docname] = titlenode
+        app.env.longtitles[app.env.docname] = longtitlenode
+
+
+def setup(app: Sphinx) -> dict[str, Any]:
+    app.add_env_collector(TitleCollector)
+
+    return {
+        'version': 'builtin',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }