Fix #1135: Make 'sphinx-apidoc' an extension

This is an alternative approach to #1135. Rather than modifying the
'build_sphinx' setuptools extension, we allow 'sphinx-apidoc' to be run
as an extension.

This is very similar to what we do with 'sphinx-autogen', which can be
run automatically using the 'autosummary_generate' configuration option
instead.

We may wish to remove the 'sphinx-apidoc' binary in the future, but
that's a decision for another day.

Signed-off-by: Stephen Finucane <stephen@that.guru>

doc/ext/apidoc.rst

@@ -0,0 +1,51 @@
+.. highlight:: rest
+
+:mod:`sphinx.ext.apidoc` -- Generate autodoc stub pages
+=======================================================
+
+.. module:: sphinx.ext.apidoc
+   :synopsis: Generate autodoc stub pages
+
+.. versionadded:: 1.7
+
+   The functionality of this extension was previously available as part of the
+   :program:`sphinx-apidoc` tool. This ability to run this automatically by way
+   of a Sphinx extension was added in 1.7.
+
+This extension generates function, method and attribute stub documentation
+pages, similar to that generated by API doc tools like Doxygen or Javadoc.
+
+.. warning::
+
+   The apidoc extension generates source files that use
+   :mod:`sphinx.ext.autodoc` to document all found modules. If any modules
+   have side effects on import, these will be executed when building
+   documentation.
+
+   If you document scripts (as opposed to library modules), make sure their
+   main routine is protected by a ``if __name__ == '__main__'`` condition.
+
+Configuration
+-------------
+
+The apidoc extension uses the following configuration values:
+
+.. confval:: apidoc_module_dir
+
+   The path to the module to document. This must be a path to a Python package.
+   This path can be a path relative to the documentation source directory or an
+   absolute path.
+
+.. confval:: apidoc_output_dir
+
+   The output directory. If it does not exist, it is created. This path is
+   relative to the documentation source directory.
+
+   Defaults to ``api``.
+
+.. confval:: apidoc_excluded_modules
+
+   An optional list of modules to exclude. These should be paths relative to
+   ``api_module_dir``. fnmatch-style wildcarding is supported.
+
+   Defaults to ``[]``.

doc/ext/builtins.rst

@@ -6,6 +6,7 @@ These extensions are built in and can be activated by respective entries in the
 
 .. toctree::
 
+   apidoc
    autodoc
    autosectionlabel
    autosummary

sphinx/ext/apidoc.py

@@ -31,12 +31,15 @@
 from sphinx import __display_version__, package_dir
 from sphinx.cmd.quickstart import EXTENSIONS
 from sphinx.locale import __
-from sphinx.util import rst
+from sphinx.util import logging, rst
 from sphinx.util.osutil import FileAvoidWrite, ensuredir, walk
 
 if False:
     # For type annotation
-    from typing import Any, List, Tuple  # NOQA
+    from typing import Any, Dict, List, Tuple  # NOQA
+    from sphinx.application import Sphinx  # NOQA
+
+logger = logging.getLogger(__name__)
 
 # automodule options
 if 'SPHINX_APIDOC_OPTIONS' in os.environ:
@@ -459,6 +462,45 @@ def main(argv=sys.argv[1:]):
     return 0
 
 
-# So program can be started with "python -m sphinx.apidoc ..."
+def builder_inited(app):
+    # type: (Sphinx) -> None
+    module_dir = app.config.apidoc_module_dir
+    output_dir = path.join(app.srcdir, app.config.apidoc_output_dir)
+    excludes = app.config.apidoc_excluded_modules
+
+    if not module_dir:
+        logger.warning("No 'apidoc_module_dir' specified; skipping API doc "
+                       "generation")
+        return
+
+    # if the path is relative, make it relative to the 'conf.py' directory
+    if not path.isabs(module_dir):
+        module_dir = path.abspath(path.join(app.srcdir, module_dir))
+
+    excludes = [path.abspath(path.join(module_dir, exc)) for exc in excludes]
+
+    # refactor this module so that we can call 'recurse_tree' like a sane
+    # person - at present there is way too much passing around of the
+    # 'optparse.Value' instance returned by 'optparse.parse_args'
+    cmd = [module_dir, '--force', '-o', output_dir]
+    if excludes:
+        cmd += excludes
+
+    main(cmd)
+
+
+def setup(app):
+    # type: (Sphinx) -> Dict[unicode, Any]
+    app.setup_extension('sphinx.ext.autodoc')  # We need autodoc to function
+
+    app.connect('builder-inited', builder_inited)
+    app.add_config_value('apidoc_module_dir', None, 'env', [str])
+    app.add_config_value('apidoc_output_dir', 'api', 'env', [str])
+    app.add_config_value('apidoc_excluded_modules', [], 'env',
+                         [[str]])
+
+    return {'version': __display_version__, 'parallel_read_safe': True}
+
+
 if __name__ == "__main__":
     main()

tests/roots/test-ext-apidoc/apidoc_dummy_module.py

@@ -0,0 +1,9 @@
+from os import *
+
+
+class Foo:
+    def __init__(self):
+        pass
+
+    def bar(self):
+        pass

tests/roots/test-ext-apidoc/conf.py

@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+
+import os
+import sys
+
+sys.path.insert(0, os.path.abspath('./'))
+
+extensions = ['sphinx.ext.apidoc']
+master_doc = 'index'
+
+apidoc_module_dir = '.'
+apidoc_excluded_modules = ['conf.py']

tests/roots/test-ext-apidoc/index.rst

@@ -0,0 +1,6 @@
+apidoc
+======
+
+.. toctree::
+
+   api/modules

tests/test_ext_apidoc.py

@@ -404,3 +404,12 @@ def test_subpackage_in_toc(make_app, apidoc):
     assert 'parent.child.foo' in parent_child
 
     assert (outdir / 'parent.child.foo.rst').isfile()
+
+
+@pytest.mark.sphinx('html', testroot='ext-apidoc')
+def test_apidoc_extension(app, status, warning):
+    app.builder.build_all()
+    assert (app.outdir / 'api').isdir()
+    assert (app.outdir / 'api' / 'modules.html').exists()
+    assert (app.outdir / 'api' / 'apidoc_dummy_module.html').exists()
+    assert not (app.outdir / 'api' / 'conf.html').exists()