gh-121970: Revert "GH-121970: Extract `pydoc_topics` into a new extension (#129116)" (#131245)

Revert "GH-121970: Extract ``pydoc_topics`` into a new extension (#129116)"

This reverts commit 01bcf13a1c.

Doc/tools/extensions/pyspecific.py

@@ -12,14 +12,20 @@
 import re
 import io
 from os import getenv, path
+from time import asctime
+from pprint import pformat
 
 from docutils import nodes
+from docutils.io import StringOutput
 from docutils.parsers.rst import directives
-from docutils.utils import unescape
+from docutils.utils import new_document, unescape
 from sphinx import addnodes
+from sphinx.builders import Builder
 from sphinx.domains.python import PyFunction, PyMethod, PyModule
 from sphinx.locale import _ as sphinx_gettext
 from sphinx.util.docutils import SphinxDirective
+from sphinx.writers.text import TextWriter, TextTranslator
+from sphinx.util.display import status_iterator
 
 # Used in conf.py and updated here by python/release-tools/run_release.py
 SOURCE_URI = 'https://github.com/python/cpython/tree/main/%s'
@@ -51,6 +57,69 @@ class PyAwaitableMethod(PyAwaitableMixin, PyMethod):
         return PyMethod.run(self)
 
 
+# Support for building "topic help" for pydoc
+
+pydoc_topic_labels = [
+    'assert', 'assignment', 'assignment-expressions', 'async',  'atom-identifiers',
+    'atom-literals', 'attribute-access', 'attribute-references', 'augassign', 'await',
+    'binary', 'bitwise', 'bltin-code-objects', 'bltin-ellipsis-object',
+    'bltin-null-object', 'bltin-type-objects', 'booleans',
+    'break', 'callable-types', 'calls', 'class', 'comparisons', 'compound',
+    'context-managers', 'continue', 'conversions', 'customization', 'debugger',
+    'del', 'dict', 'dynamic-features', 'else', 'exceptions', 'execmodel',
+    'exprlists', 'floating', 'for', 'formatstrings', 'function', 'global',
+    'id-classes', 'identifiers', 'if', 'imaginary', 'import', 'in', 'integers',
+    'lambda', 'lists', 'naming', 'nonlocal', 'numbers', 'numeric-types',
+    'objects', 'operator-summary', 'pass', 'power', 'raise', 'return',
+    'sequence-types', 'shifting', 'slicings', 'specialattrs', 'specialnames',
+    'string-methods', 'strings', 'subscriptions', 'truth', 'try', 'types',
+    'typesfunctions', 'typesmapping', 'typesmethods', 'typesmodules',
+    'typesseq', 'typesseq-mutable', 'unary', 'while', 'with', 'yield'
+]
+
+
+class PydocTopicsBuilder(Builder):
+    name = 'pydoc-topics'
+
+    default_translator_class = TextTranslator
+
+    def init(self):
+        self.topics = {}
+        self.secnumbers = {}
+
+    def get_outdated_docs(self):
+        return 'all pydoc topics'
+
+    def get_target_uri(self, docname, typ=None):
+        return ''  # no URIs
+
+    def write(self, *ignored):
+        writer = TextWriter(self)
+        for label in status_iterator(pydoc_topic_labels,
+                                     'building topics... ',
+                                     length=len(pydoc_topic_labels)):
+            if label not in self.env.domaindata['std']['labels']:
+                self.env.logger.warning(f'label {label!r} not in documentation')
+                continue
+            docname, labelid, sectname = self.env.domaindata['std']['labels'][label]
+            doctree = self.env.get_and_resolve_doctree(docname, self)
+            document = new_document('<section node>')
+            document.append(doctree.ids[labelid])
+            destination = StringOutput(encoding='utf-8')
+            writer.write(document, destination)
+            self.topics[label] = writer.output
+
+    def finish(self):
+        f = open(path.join(self.outdir, 'topics.py'), 'wb')
+        try:
+            f.write('# -*- coding: utf-8 -*-\n'.encode('utf-8'))
+            f.write(('# Autogenerated by Sphinx on %s\n' % asctime()).encode('utf-8'))
+            f.write('# as part of the release process.\n'.encode('utf-8'))
+            f.write(('topics = ' + pformat(self.topics) + '\n').encode('utf-8'))
+        finally:
+            f.close()
+
+
 # Support for documenting Opcodes
 
 opcode_sig_re = re.compile(r'(\w+(?:\+\d)?)(?:\s*\((.*)\))?')
@@ -127,6 +196,7 @@ def patch_pairindextypes(app, _env) -> None:
 
 
 def setup(app):
+    app.add_builder(PydocTopicsBuilder)
     app.add_object_type('opcode', 'opcode', '%s (opcode)', parse_opcode_signature)
     app.add_object_type('pdbcommand', 'pdbcmd', '%s (pdb command)', parse_pdb_command)
     app.add_object_type('monitoring-event', 'monitoring-event', '%s (monitoring event)', parse_monitoring_event)