intersphinx: Add :intersphinx:***: role

4 files changed, 177 insertions, 4 deletions

diff --git a/sphinx/ext/intersphinx.py b/sphinx/ext/intersphinx.py
index 7f3588ade..146e0c246 100644
--- a/sphinx/ext/intersphinx.py
+++ b/sphinx/ext/intersphinx.py
@@ -29,12 +29,13 @@ import posixpath
 import sys
 import time
 from os import path
-from typing import IO, Any, Dict, List, Optional, Tuple
+from types import ModuleType
+from typing import IO, Any, Dict, List, Optional, Tuple, cast
 from urllib.parse import urlsplit, urlunsplit
 
 from docutils import nodes
-from docutils.nodes import Element, TextElement
-from docutils.utils import relative_path
+from docutils.nodes import Element, Node, TextElement, system_message
+from docutils.utils import Reporter, relative_path
 
 import sphinx
 from sphinx.addnodes import pending_xref
@@ -43,10 +44,13 @@ from sphinx.builders.html import INVENTORY_FILENAME
 from sphinx.config import Config
 from sphinx.domains import Domain
 from sphinx.environment import BuildEnvironment
+from sphinx.errors import ExtensionError
 from sphinx.locale import _, __
+from sphinx.transforms.post_transforms import ReferencesResolver
 from sphinx.util import logging, requests
+from sphinx.util.docutils import CustomReSTDispatcher, SphinxRole
 from sphinx.util.inventory import InventoryFile
-from sphinx.util.typing import Inventory, InventoryItem
+from sphinx.util.typing import Inventory, InventoryItem, RoleFunction
 
 logger = logging.getLogger(__name__)
 
@@ -466,6 +470,115 @@ def missing_reference(app: Sphinx, env: BuildEnvironment, node: pending_xref,
     return resolve_reference_detect_inventory(env, node, contnode)
 
 
+class IntersphinxDispatcher(CustomReSTDispatcher):
+    """Custom dispatcher for intersphinx role.
+
+    This enables :intersphinx:***: roles on parsing reST document.
+    """
+
+    def __init__(self) -> None:
+        super().__init__()
+
+    def role(self, role_name: str, language_module: ModuleType, lineno: int, reporter: Reporter
+             ) -> Tuple[RoleFunction, List[system_message]]:
+        if role_name.split(':')[0] == 'intersphinx':
+            return IntersphinxRole(), []
+        else:
+            return super().role(role_name, language_module, lineno, reporter)
+
+
+class IntersphinxRole(SphinxRole):
+    def run(self) -> Tuple[List[Node], List[system_message]]:
+        role_name = self.get_role_name(self.name)
+        if role_name is None:
+            logger.warning(__('role not found: %s'), self.name,
+                           location=(self.env.docname, self.lineno))
+            return [], []
+
+        result, messages = self.invoke_role(role_name)
+        for node in result:
+            if isinstance(node, pending_xref):
+                node['intersphinx'] = True
+
+        return result, messages
+
+    def get_role_name(self, name: str) -> Optional[Tuple[str, str]]:
+        names = name.split(':')
+        if len(names) == 2:
+            # :intersphinx:role:
+            domain = self.env.temp_data.get('default_domain')
+            role = names[1]
+        elif len(names) == 3:
+            # :intersphinx:domain:role:
+            domain = names[1]
+            role = names[2]
+        else:
+            return None
+
+        if domain and self.is_existent_role(domain, role):
+            return (domain, role)
+        elif self.is_existent_role('std', role):
+            return ('std', role)
+        else:
+            return None
+
+    def is_existent_role(self, domain_name: str, role_name: str) -> bool:
+        try:
+            domain = self.env.get_domain(domain_name)
+            if role_name in domain.roles:
+                return True
+            else:
+                return False
+        except ExtensionError:
+            return False
+
+    def invoke_role(self, role: Tuple[str, str]) -> Tuple[List[Node], List[system_message]]:
+        domain = self.env.get_domain(role[0])
+        if domain:
+            role_func = domain.role(role[1])
+
+            return role_func(':'.join(role), self.rawtext, self.text, self.lineno,
+                             self.inliner, self.options, self.content)
+        else:
+            return [], []
+
+
+class IntersphinxRoleResolver(ReferencesResolver):
+    """pending_xref node resolver for intersphinx role.
+
+    This resolves pending_xref nodes generated by :intersphinx:***: role.
+    """
+
+    default_priority = ReferencesResolver.default_priority - 1
+
+    def run(self, **kwargs: Any) -> None:
+        for node in self.document.traverse(pending_xref):
+            if 'intersphinx' in node:
+                contnode = cast(nodes.TextElement, node[0].deepcopy())
+                refdoc = node.get('refdoc', self.env.docname)
+                try:
+                    domain = self.env.get_domain(node['refdomain'])
+                except Exception:
+                    domain = None
+
+                newnode = missing_reference(self.app, self.env, node, contnode)
+                if newnode is None:
+                    self.warn_missing_reference(refdoc, node['reftype'], node['reftarget'],
+                                                node, domain)
+                else:
+                    node.replace_self(newnode)
+
+
+def install_dispatcher(app: Sphinx, docname: str, source: List[str]) -> None:
+    """Enable IntersphinxDispatcher.
+
+    .. note:: The installed dispatcher will uninstalled on disabling sphinx_domain
+              automatically.
+    """
+    dispatcher = IntersphinxDispatcher()
+    dispatcher.enable()
+
+
 def normalize_intersphinx_mapping(app: Sphinx, config: Config) -> None:
     for key, value in config.intersphinx_mapping.copy().items():
         try:
@@ -497,7 +610,9 @@ def setup(app: Sphinx) -> Dict[str, Any]:
     app.add_config_value('intersphinx_disabled_reftypes', [], True)
     app.connect('config-inited', normalize_intersphinx_mapping, priority=800)
     app.connect('builder-inited', load_mappings)
+    app.connect('source-read', install_dispatcher)
     app.connect('missing-reference', missing_reference)
+    app.add_post_transform(IntersphinxRoleResolver)
     return {
         'version': sphinx.__display_version__,
         'env_version': 1,
diff --git a/tests/roots/test-ext-intersphinx-role/conf.py b/tests/roots/test-ext-intersphinx-role/conf.py
new file mode 100644
index 000000000..9485eb207
--- /dev/null
+++ b/tests/roots/test-ext-intersphinx-role/conf.py
@@ -0,0 +1 @@
+extensions = ['sphinx.ext.intersphinx']
diff --git a/tests/roots/test-ext-intersphinx-role/index.rst b/tests/roots/test-ext-intersphinx-role/index.rst
new file mode 100644
index 000000000..b8a7d8716
--- /dev/null
+++ b/tests/roots/test-ext-intersphinx-role/index.rst
@@ -0,0 +1,11 @@
+:intersphinx:py:mod:`module1`
+:intersphinx:py:mod:`inv:module2`
+
+.. py:module:: module1
+
+:intersphinx:py:func:`func`
+:intersphinx:py:meth:`Foo.bar`
+
+:intersphinx:c:func:`CFunc`
+:intersphinx:doc:`docname`
+:intersphinx:option:`ls -l`
diff --git a/tests/test_ext_intersphinx.py b/tests/test_ext_intersphinx.py
index 7f369e9a3..9801bb81f 100644
--- a/tests/test_ext_intersphinx.py
+++ b/tests/test_ext_intersphinx.py
@@ -524,3 +524,49 @@ def test_inspect_main_url(capsys):
     stdout, stderr = capsys.readouterr()
     assert stdout.startswith("c:function\n")
     assert stderr == ""
+
+
+@pytest.mark.sphinx('html', testroot='ext-intersphinx-role')
+def test_intersphinx_role(app):
+    inv_file = app.srcdir / 'inventory'
+    inv_file.write_bytes(inventory_v2)
+    app.config.intersphinx_mapping = {
+        'inv': ('http://example.org/', inv_file),
+    }
+    app.config.intersphinx_cache_limit = 0
+    app.config.nitpicky = True
+
+    # load the inventory and check if it's done correctly
+    normalize_intersphinx_mapping(app, app.config)
+    load_mappings(app)
+
+    app.build()
+    content = (app.outdir / 'index.html').read_text()
+
+    # :intersphinx:py:module:`module1`
+    assert ('<a class="reference external" href="http://example.org/foo.html#module-module1"'
+            ' title="(in foo v2.0)">' in content)
+
+    # :intersphinx:py:module:`inv:module2`
+    assert ('<a class="reference external" href="http://example.org/foo.html#module-module2"'
+            ' title="(in foo v2.0)">' in content)
+
+    # py:module + :intersphinx:py:function:`func`
+    assert ('<a class="reference external" href="http://example.org/sub/foo.html#module1.func"'
+            ' title="(in foo v2.0)">' in content)
+
+    # py:module + :intersphinx:py:method:`Foo.bar`
+    assert ('<a class="reference external" href="http://example.org/index.html#foo.Bar.baz"'
+            ' title="(in foo v2.0)">' in content)
+
+    # :intersphinx:c:function:`CFunc`
+    assert ('<a class="reference external" href="http://example.org/cfunc.html#CFunc"'
+            ' title="(in foo v2.0)">' in content)
+
+    # :intersphinx:doc:`docname`
+    assert ('<a class="reference external" href="http://example.org/docname.html"'
+            ' title="(in foo v2.0)">' in content)
+
+    # :intersphinx:option:`ls -l`
+    assert ('<a class="reference external" href="http://example.org/index.html#cmdoption-ls-l"'
+            ' title="(in foo v2.0)">' in content)