Simple extension to collect scattered footnotes on document into last

collect_footnotes.py

"""
Copyright 2023 attakei

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
from sphinx.application import Sphinx
from sphinx.util.docutils import nodes


def collect_footnotes(app: Sphinx, doctree: nodes.document):
    """Pick footnotes on document, and collect into section node.
    
    Section does not have title and ref, and be appended end of document.
    """
    footnotes = nodes.section()
    for footnote in doctree.traverse(nodes.footnote):
        footnote.parent.remove(footnote)
        footnotes.append(footnote)
    if len(footnotes.children):
        doctree.append(footnotes)


def setup(app: Sphinx):
    app.connect("doctree-read", collect_footnotes)