Restructure changelog generation as a Sphinx extension

conf.py

@@ -22,8 +22,6 @@ import re
 import shlex  # pylint:disable=unused-import
 import sys
 
-sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__)), 'docs'))
-from gen_changelog import generate_changelog
 
 # -- Support :dfhack-keybind:`command` ------------------------------------
 # this is a custom directive that pulls info from dfhack.init-example
@@ -180,19 +178,23 @@ def all_keybinds_documented():
 
 
 # Actually call the docs generator and run test
-generate_changelog()
 write_script_docs()
 all_keybinds_documented()
 
 # -- General configuration ------------------------------------------------
 
+sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__)), 'docs', 'sphinx_extensions'))
+
 # If your documentation needs a minimal Sphinx version, state it here.
 needs_sphinx = '1.8'
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ['sphinx.ext.extlinks']
+extensions = [
+    'sphinx.ext.extlinks',
+    'dfhack.changelog',
+]
 
 # This config value must be a dictionary of external sites, mapping unique
 # short alias names to a base URL and a prefix.

docs/sphinx_extensions/dfhack/changelog.py

@@ -283,3 +283,17 @@ if __name__ == '__main__':
                     print('stable missing: ' + description)
                 if description not in content_dev:
                     print('dev missing: ' + description)
+
+
+def sphinx_entrypoint(app, config):
+    generate_changelog()
+
+
+def setup(app):
+    app.connect('config-inited', sphinx_entrypoint)
+
+    return {
+        'version': '0.1',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }