feat: Provide hook interface, use it to expand identifiers, attach ad…

…ditional context to references, and give more context around unmapped identifers

Issue-54: #54
PR-mkdocstrings#666: mkdocstrings/mkdocstrings#666

src/mkdocs_autorefs/plugin.py

@@ -302,7 +302,8 @@ def on_post_page(self, output: str, page: Page, **kwargs: Any) -> str:  # noqa:
         fixed_output, unmapped = fix_refs(output, url_mapper, _legacy_refs=self.legacy_refs)
 
         if unmapped and log.isEnabledFor(logging.WARNING):
-            for ref in unmapped:
-                log.warning(f"{page.file.src_path}: Could not find cross-reference target '[{ref}]'")
+            for ref, context in unmapped:
+                message = f"from {context.filepath}:{context.lineno}: ({context.origin}) " if context else ""
+                log.warning(f"{page.file.src_path}: {message}Could not find cross-reference target '{ref}'")
 
         return fixed_output

src/mkdocs_autorefs/references.py

@@ -5,6 +5,8 @@
 import logging
 import re
 import warnings
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
 from functools import lru_cache
 from html import escape, unescape
 from html.parser import HTMLParser
@@ -20,6 +22,8 @@
 from markdown.util import HTML_PLACEHOLDER_RE, INLINE_PLACEHOLDER_RE
 
 if TYPE_CHECKING:
+    from pathlib import Path
+
     from markdown import Markdown
 
     from mkdocs_autorefs.plugin import AutorefsPlugin
@@ -59,10 +63,56 @@ def __getattr__(name: str) -> Any:
 """
 
 
+class AutorefsHookInterface(ABC):
+    """An interface for hooking into how AutoRef handles inline references."""
+
+    @dataclass
+    class Context:
+        """The context around an auto-reference."""
+
+        domain: str
+        role: str
+        origin: str
+        filepath: str | Path
+        lineno: int
+
+        def as_dict(self) -> dict[str, str]:
+            """Convert the context to a dictionary of HTML attributes."""
+            return {
+                "domain": self.domain,
+                "role": self.role,
+                "origin": self.origin,
+                "filepath": str(self.filepath),
+                "lineno": str(self.lineno),
+            }
+
+    @abstractmethod
+    def expand_identifier(self, identifier: str) -> str:
+        """Expand an identifier in a given context.
+
+        Parameters:
+            identifier: The identifier to expand.
+
+        Returns:
+            The expanded identifier.
+        """
+        raise NotImplementedError
+
+    @abstractmethod
+    def get_context(self) -> AutorefsHookInterface.Context:
+        """Get the current context.
+
+        Returns:
+            The current context.
+        """
+        raise NotImplementedError
+
+
 class AutorefsInlineProcessor(ReferenceInlineProcessor):
     """A Markdown extension to handle inline references."""
 
     name: str = "mkdocs-autorefs"
+    hook: AutorefsHookInterface | None = None
 
     def __init__(self, *args: Any, **kwargs: Any) -> None:  # noqa: D107
         super().__init__(REFERENCE_RE, *args, **kwargs)
@@ -145,6 +195,9 @@ def _make_tag(self, identifier: str, text: str) -> Element:
             A new element.
         """
         el = Element("autoref")
+        if self.hook:
+            identifier = self.hook.expand_identifier(identifier)
+            el.attrib.update(self.hook.get_context().as_dict())
         el.set("identifier", identifier)
         el.text = text
         return el
@@ -177,7 +230,10 @@ def relative_url(url_a: str, url_b: str) -> str:
 
 
 # YORE: Bump 2: Remove block.
-def _legacy_fix_ref(url_mapper: Callable[[str], str], unmapped: list[str]) -> Callable:
+def _legacy_fix_ref(
+    url_mapper: Callable[[str], str],
+    unmapped: list[tuple[str, AutorefsHookInterface.Context | None]],
+) -> Callable:
     """Return a `repl` function for [`re.sub`](https://docs.python.org/3/library/re.html#re.sub).
 
     In our context, we match Markdown references and replace them with HTML links.
@@ -210,7 +266,7 @@ def inner(match: Match) -> str:
                 return title
             if kind == "autorefs-optional-hover":
                 return f'<span title="{identifier}">{title}</span>'
-            unmapped.append(identifier)
+            unmapped.append((identifier, None))
             if title == identifier:
                 return f"[{identifier}][]"
             return f"[{title}][{identifier}]"
@@ -233,7 +289,30 @@ def inner(match: Match) -> str:
 
 
 class _AutorefsAttrs(dict):
-    _handled_attrs: ClassVar[set[str]] = {"identifier", "optional", "hover", "class"}
+    _handled_attrs: ClassVar[set[str]] = {
+        "identifier",
+        "optional",
+        "hover",
+        "class",
+        "domain",
+        "role",
+        "origin",
+        "filepath",
+        "lineno",
+    }
+
+    @property
+    def context(self) -> AutorefsHookInterface.Context | None:
+        try:
+            return AutorefsHookInterface.Context(
+                domain=self["domain"],
+                role=self["role"],
+                origin=self["origin"],
+                filepath=self["filepath"],
+                lineno=int(self["lineno"]),
+            )
+        except KeyError:
+            return None
 
     @property
     def remaining(self) -> str:
@@ -257,7 +336,10 @@ def handle_starttag(self, tag: str, attrs: list[tuple[str, str | None]]) -> None
 _html_attrs_parser = _HTMLAttrsParser()
 
 
-def fix_ref(url_mapper: Callable[[str], str], unmapped: list[str]) -> Callable:
+def fix_ref(
+    url_mapper: Callable[[str], str],
+    unmapped: list[tuple[str, AutorefsHookInterface.Context | None]],
+) -> Callable:
     """Return a `repl` function for [`re.sub`](https://docs.python.org/3/library/re.html#re.sub).
 
     In our context, we match Markdown references and replace them with HTML links.
@@ -290,7 +372,7 @@ def inner(match: Match) -> str:
                 if hover:
                     return f'<span title="{identifier}">{title}</span>'
                 return title
-            unmapped.append(identifier)
+            unmapped.append((identifier, attrs.context))
             if title == identifier:
                 return f"[{identifier}][]"
             return f"[{title}][{identifier}]"
@@ -310,7 +392,12 @@ def inner(match: Match) -> str:
 
 
 # YORE: Bump 2: Replace `, *, _legacy_refs: bool = True` with `` within line.
-def fix_refs(html: str, url_mapper: Callable[[str], str], *, _legacy_refs: bool = True) -> tuple[str, list[str]]:
+def fix_refs(
+    html: str,
+    url_mapper: Callable[[str], str],
+    *,
+    _legacy_refs: bool = True,
+) -> tuple[str, list[tuple[str, AutorefsHookInterface.Context | None]]]:
     """Fix all references in the given HTML text.
 
     Arguments:
@@ -319,9 +406,9 @@ def fix_refs(html: str, url_mapper: Callable[[str], str], *, _legacy_refs: bool
             such as [mkdocs_autorefs.plugin.AutorefsPlugin.get_item_url][].
 
     Returns:
-        The fixed HTML.
+        The fixed HTML, and a list of unmapped identifiers (string and optional context).
     """
-    unmapped: list[str] = []
+    unmapped: list[tuple[str, AutorefsHookInterface.Context | None]] = []
     html = AUTOREF_RE.sub(fix_ref(url_mapper, unmapped), html)
 
     # YORE: Bump 2: Remove block.

tests/test_references.py

@@ -9,7 +9,7 @@
 import pytest
 
 from mkdocs_autorefs.plugin import AutorefsPlugin
-from mkdocs_autorefs.references import AutorefsExtension, fix_refs, relative_url
+from mkdocs_autorefs.references import AutorefsExtension, AutorefsHookInterface, fix_refs, relative_url
 
 
 @pytest.mark.parametrize(
@@ -46,7 +46,7 @@ def run_references_test(
     url_map: dict[str, str],
     source: str,
     output: str,
-    unmapped: list[str] | None = None,
+    unmapped: list[tuple[str, AutorefsHookInterface.Context | None]] | None = None,
     from_url: str = "page.html",
     extensions: Mapping = {},
 ) -> None:
@@ -169,7 +169,7 @@ def test_missing_reference() -> None:
         url_map={"NotFoo": "foo.html#NotFoo"},
         source="[Foo][]",
         output="<p>[Foo][]</p>",
-        unmapped=["Foo"],
+        unmapped=[("Foo", None)],
     )
 
 
@@ -179,7 +179,7 @@ def test_missing_reference_with_markdown_text() -> None:
         url_map={"NotFoo": "foo.html#NotFoo"},
         source="[`Foo`][Foo]",
         output="<p>[<code>Foo</code>][Foo]</p>",
-        unmapped=["Foo"],
+        unmapped=[("Foo", None)],
     )
 
 
@@ -189,7 +189,7 @@ def test_missing_reference_with_markdown_id() -> None:
         url_map={"Foo": "foo.html#Foo", "NotFoo": "foo.html#NotFoo"},
         source="[Foo][*NotFoo*]",
         output="<p>[Foo][*NotFoo*]</p>",
-        unmapped=["*NotFoo*"],
+        unmapped=[("*NotFoo*", None)],
     )
 
 
@@ -199,7 +199,7 @@ def test_missing_reference_with_markdown_implicit() -> None:
         url_map={"Foo-bar": "foo.html#Foo-bar"},
         source="[*Foo-bar*][] and [`Foo`-bar][]",
         output="<p>[<em>Foo-bar</em>][*Foo-bar*] and [<code>Foo</code>-bar][]</p>",
-        unmapped=["*Foo-bar*"],
+        unmapped=[("*Foo-bar*", None)],
     )
 
 
@@ -224,7 +224,7 @@ def test_legacy_custom_required_reference() -> None:
     with pytest.warns(DeprecationWarning, match="`span` elements are deprecated"):
         output, unmapped = fix_refs(source, url_map.__getitem__)
     assert output == '[foo][bar] <a class="autorefs autorefs-internal" href="ok.html#ok">ok</a>'
-    assert unmapped == ["bar"]
+    assert unmapped == [("bar", None)]
 
 
 def test_custom_required_reference() -> None:
@@ -233,7 +233,7 @@ def test_custom_required_reference() -> None:
     source = "<autoref identifier=bar>foo</autoref> <autoref identifier=ok>ok</autoref>"
     output, unmapped = fix_refs(source, url_map.__getitem__)
     assert output == '[foo][bar] <a class="autorefs autorefs-internal" href="ok.html#ok">ok</a>'
-    assert unmapped == ["bar"]
+    assert unmapped == [("bar", None)]
 
 
 def test_legacy_custom_optional_reference() -> None: