Cooperate with linkcheck builder

docs/rn.rst

@@ -36,4 +36,4 @@ Release notes
 0.0.0 (2020-09-09)
 ******************
 
-Initial release.
+Initial release.

docs/usage.rst

@@ -108,3 +108,16 @@ Occasionally, you have to move complete documentation to a new home. It's easy w
    }
 
 .. tip:: To help search engines to understand the transfer, update (or set) `html_baseurl <https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-html_baseurl>`_ option to the new website, too.
+
+
+Checking your redirects
+***********************
+
+Sphinx has a linkcheck_ builder for finding broken links in your
+documentation.  This extension cooperates with it so that redirects to
+external websites will be checked too.
+
+.. _linkcheck: https://www.sphinx-doc.org/en/master/usage/builders/index.html#sphinx.builders.linkcheck.CheckExternalLinksBuilder
+
+Checking redirects to another page in the same documentation is not
+supported yet.

requirements.txt

@@ -1 +1 @@
-sphinx
+sphinx>=7.1

setup.py

@@ -11,7 +11,7 @@
     long_description=open("README.rst", encoding="utf-8").read(),
     long_description_content_type="text/x-rst",
     packages=["sphinx_reredirects"],
-    install_requires=["sphinx"],
+    install_requires=["sphinx>=7.1"],
     python_requires=">=3.5",
     setup_requires=["wheel"],
     classifiers=[

sphinx_reredirects/__init__.py

@@ -3,8 +3,10 @@
 from pathlib import Path
 from string import Template
 from typing import Dict, Mapping, Optional, Sequence
+from urllib.parse import urlparse
 
 from sphinx.application import Sphinx
+from sphinx.builders.linkcheck import CheckExternalLinksBuilder, Hyperlink
 from sphinx.util import logging
 from sphinx.util.osutil import SEP
 
@@ -26,6 +28,7 @@ def setup(app: Sphinx) -> Dict:
     Extension setup, called by Sphinx
     """
     app.connect("html-collect-pages", init)
+    app.connect("builder-inited", collect_redirects_for_linkcheck)
     app.add_config_value(OPTION_REDIRECTS, OPTION_REDIRECTS_DEFAULT, "env")
     app.add_config_value(OPTION_TEMPLATE_FILE, OPTION_TEMPLATE_FILE_DEFAULT, "env")
     return dict(parallel_read_safe=True)
@@ -160,3 +163,22 @@ def _render_redirect_template(self, to_uri: str) -> str:
         content = Template(redirect_template).substitute({"to_uri": to_uri})
 
         return content
+
+
+def collect_redirects_for_linkcheck(app):
+    if not isinstance(app.builder, CheckExternalLinksBuilder):
+        return
+
+    rr = Reredirects(app)
+    redirects = rr.grab_redirects()
+
+    for docname, target in redirects.items():
+        if new_target := app.emit_firstresult("linkcheck-process-uri", target):
+            target = new_target
+        if urlparse(target).scheme not in ("http", "https"):
+            # Checking redirects to other pages of the same documentation is not
+            # supported for now.
+            continue
+        docpath = app.env.doc2path(docname)
+        hyperlink = Hyperlink(uri=target, docname=docname, docpath=docpath, lineno=-1)
+        app.builder.hyperlinks[target] = hyperlink

test-requirements.txt

@@ -1 +1 @@
-sphinx==5.3.0
+sphinx==7.2.6