Add codeautolink_warn_on_no_backreference config

Highlights where reference documentation does not have a corresponding tutorial or how-to

Closes #161

Author: cmarqu

docs/src/reference.rst

@@ -65,6 +65,13 @@ Configuration
    Type: ``bool``. Issue warning when failing to resolve the canonical location
    of an object that a code element references. Defaults to :code:`False`.
 
+.. confval:: codeautolink_warn_on_no_backreference
+
+   Type: ``bool``. Issue warning when no backreference could be found
+   from reference documentation using the :rst:dir:`autolink-examples` table.
+   This highlights objects for which no tutorial, example or how-to exists.
+   Defaults to :code:`False`.
+
 Directives
 ----------
 .. rst:directive:: .. autolink-examples:: object

docs/src/release_notes.rst

@@ -8,6 +8,12 @@ These release notes are based on
 sphinx-codeautolink adheres to
 `Semantic Versioning <https://semver.org>`_.
 
+0.16.3 (unreleased)
+-------------------
+- Introduce :confval:`codeautolink_warn_on_no_backreference` to highlight
+  where reference documentation does not appear to have
+  a corresponding tutorial or how-to (:issue:`161`)
+
 0.16.2 (2025-01-16)
 -------------------
 - Fix regression in not handling malformed return types (:issue:`159`)

src/sphinx_codeautolink/__init__.py

@@ -43,6 +43,12 @@ def setup(app: Sphinx):
         rebuild="html",
         types=[bool],
     )
+    app.add_config_value(
+        "codeautolink_warn_on_no_backreference",
+        default=False,
+        rebuild="html",
+        types=[bool],
+    )
 
     app.add_directive("autolink-concat", directive.Concat)
     app.add_directive("autolink-examples", directive.Examples)

src/sphinx_codeautolink/extension/__init__.py

@@ -74,6 +74,7 @@ def __init__(self) -> None:
         self.inventory_map: dict[str, str] = {}
         self.warn_missing_inventory = None
         self.warn_failed_resolve = None
+        self.warn_no_backreference = None
 
         # Populated once
         self.outdated_docs: set[str] = set()
@@ -103,6 +104,7 @@ def build_inited(self, app) -> None:
         self.inventory_map = app.config.codeautolink_inventory_map
         self.warn_missing_inventory = app.config.codeautolink_warn_on_missing_inventory
         self.warn_failed_resolve = app.config.codeautolink_warn_on_failed_resolve
+        self.warn_no_backreference = app.config.codeautolink_warn_on_no_backreference
 
         # Append static resources path so references in setup() are valid
         app.config.html_static_path.append(
@@ -255,7 +257,11 @@ def generate_backref_tables(self, app, doctree, docname):
             rm_vis = RemoveExtensionVisitor(doctree)
             return doctree.walkabout(rm_vis)
 
-        visitor = CodeRefsVisitor(doctree, code_refs=self.code_refs)
+        visitor = CodeRefsVisitor(
+            doctree,
+            code_refs=self.code_refs,
+            warn_no_backreference=self.warn_no_backreference,
+        )
         doctree.walk(visitor)
         return None
 

src/sphinx_codeautolink/extension/backref.py

@@ -4,6 +4,8 @@
 
 from docutils import nodes
 
+from sphinx_codeautolink.warn import logger, warn_type
+
 from .directive import DeferredExamples
 
 
@@ -56,10 +58,15 @@ class CodeRefsVisitor(nodes.SparseNodeVisitor):
     """Replace :class:`DeferredCodeReferences` with table of concrete references."""
 
     def __init__(
-        self, *args, code_refs: dict[str, list[CodeExample]], **kwargs
+        self,
+        *args,
+        code_refs: dict[str, list[CodeExample]],
+        warn_no_backreference: bool = False,
+        **kwargs,
     ) -> None:
         super().__init__(*args, **kwargs)
         self.code_refs = code_refs
+        self.warn_no_backreference = warn_no_backreference
 
     def unknown_departure(self, node) -> None:
         """Ignore unknown nodes."""
@@ -79,6 +86,11 @@ def unknown_visit(self, node) -> None:
         items = sorted(set(items))
 
         if not items:
+            if self.warn_no_backreference:
+                msg = f"No backreference for: '{node.ref}'"
+                logger.warning(
+                    msg, type=warn_type, subtype="no_backreference", location=node
+                )
             # Remove surrounding paragraph too
             node.parent.parent.remove(node.parent)
             return

tests/extension/__init__.py

@@ -26,6 +26,7 @@
 }
 codeautolink_warn_on_missing_inventory = True
 codeautolink_warn_on_failed_resolve = True
+codeautolink_warn_on_no_backreference = False
 """
 
 any_whitespace = re.compile(r"\s*")