fix(core/dfn): treat internal slots as IDL attributes

src/core/dfn.js

@@ -2,7 +2,7 @@
 // Module core/dfn
 // - Finds all <dfn> elements and populates definitionMap to identify them.
 
-import { getDfnTitles, norm } from "./utils.js";
+import { getDfnTitles, norm, showError } from "./utils.js";
 import { registerDefinition } from "./dfn-map.js";
 
 export const name = "core/dfn";
@@ -12,10 +12,9 @@ export function run() {
     const titles = getDfnTitles(dfn);
     registerDefinition(dfn, titles);
 
-    // Treat Internal Slots as IDL.
-    if (!dfn.dataset.dfnType && /^\[\[\w+\]\]$/.test(titles[0])) {
-      dfn.dataset.dfnType = "idl";
-    }
+    const [firstTitle] = titles;
+
+    associateInternalSlotWithIDL(firstTitle, dfn);
 
     // Per https://tabatkins.github.io/bikeshed/#dfn-export, a dfn with dfnType
     // other than dfn and not marked with data-no-export is to be exported.
@@ -26,9 +25,36 @@ export function run() {
     }
 
     // Only add `lt`s that are different from the text content
-    if (titles.length === 1 && titles[0] === norm(dfn.textContent)) {
+    if (titles.length === 1 && firstTitle === norm(dfn.textContent)) {
       return;
     }
     dfn.dataset.lt = titles.join("|");
   });
 }
+/**
+ *
+ * @param {string} title
+ * @param {HTMLElement} dfn
+ */
+function associateInternalSlotWithIDL(title, dfn) {
+  if (!/^\[\[\w+\]\]$/.test(title)) return;
+  if (!dfn.dataset.idl) {
+    dfn.dataset.idl = "";
+  }
+
+  // Automatically use the closest data-dfn-for as the parent.
+  /** @type HTMLElement */
+  const parent = dfn.closest("[data-dfn-for]");
+  if (parent && dfn !== parent && parent.dataset.dfnFor) {
+    dfn.dataset.dfnFor = parent.dataset.dfnFor;
+  }
+
+  // Assure that it's data-dfn-for= something.
+  if (!dfn.dataset.dfnFor) {
+    const msg = `Internal slot "${title}" must be associated with a WebIDL interface.`;
+    const hint =
+      "Use a `data-dfn-for` attribute to associate this dfn with a WebIDL interface.";
+    showError(msg, name, { hint, elements: [dfn] });
+  }
+  dfn.dataset.dfnType = "attribute";
+}

tests/spec/core/dfn-spec.js

@@ -153,4 +153,57 @@ describe("Core — Definitions", () => {
       expect(el.hash).toBe("#dfn-first");
     }
   });
+
+  describe("internal slot definitions", () => {
+    const body = `
+      <section data-dfn-for="Test" data-cite="HTML">
+        <h2>Internal slots</h2>
+        <pre class="idl">
+          [Exposed=Window]
+          interface Foo{};
+        </pre>
+        <p>
+          <dfn id="simple">[[\\slot]]</dfn>
+          <dfn id="parent" data-dfn-for="Window">[[\\slot]]</dfn>
+          <dfn id="broken" data-dfn-for="">[[\\broken]]</dfn>
+        </p>
+        <section data-dfn-for="">
+          <h2>.</h2>
+          <p>
+            <dfn id="broken-parent">[[\\broken]]</dfn>
+          </p>
+        </section>
+        <p>
+        {{Test/[[slot]]}}
+        {{Window/[[slot]]}}
+        </p>
+      </section>
+    `;
+    it("sets the data-dfn-type an idl attribute", async () => {
+      const ops = makeStandardOps(null, body);
+      const doc = await makeRSDoc(ops);
+      const dfn = doc.getElementById("simple");
+      expect(dfn.textContent).toBe("[[slot]]");
+      expect(dfn.dataset.dfnType).toBe("attribute");
+      expect(dfn.dataset.idl).toBe("");
+    });
+
+    it("when data-dfn-for is missing, it use the closes data-dfn-for as parent", async () => {
+      const ops = makeStandardOps(null, body);
+      const doc = await makeRSDoc(ops);
+      const dfn = doc.getElementById("simple");
+      expect(dfn.dataset.dfnFor).toBe("Test");
+      const dfnWithParent = doc.getElementById("parent");
+      expect(dfnWithParent.dataset.dfnFor).toBe("Window");
+    });
+
+    it("errors if the internal slot is not for something", async () => {
+      const ops = makeStandardOps(null, body);
+      const doc = await makeRSDoc(ops);
+      const dfnErrors = doc.respec.errors.filter(
+        ({ plugin }) => plugin === "core/dfn"
+      );
+      expect(dfnErrors).toHaveSize(2);
+    });
+  });
 });

tests/spec/core/link-to-dfn-spec.js

@@ -9,7 +9,9 @@ describe("Core — Link to definitions", () => {
     const bodyText = `
       <section>
         <h2>Test section</h2>
-        <p><dfn>[[\\test]]</dfn><a id="testAnchor">[[\\test]]</a>
+        <p>
+          <dfn data-dfn-for="Window">[[\\test]]</dfn>
+          <a data-link-for="Window" id="testAnchor">[[\\test]]</a>
       </section>`;
     const ops = makeStandardOps(null, bodyText);
     const doc = await makeRSDoc(ops);

tests/spec/core/simple.html

@@ -30,7 +30,6 @@ <h2>Some title</h2>
     Some content
   </p>
   <p><dfn id="custom_id(¡™£¢∞§¶•ªº)">custom id</dfn></p>
-  <p><dfn>[[\escapedSlot]]</dfn> <a>[[\escapedSlot]]</a></p>
 </section>
 <section data-dfn-for="Test">
   <h2><dfn>Test</dfn> interface</h2>
@@ -42,5 +41,9 @@ <h2><dfn>Test</dfn> interface</h2>
   </pre>
   <section>
     <h3><dfn>foo()</dfn> method</h3>
+    <p>
+      <dfn>[[\escapedSlot]]</dfn>
+      {{Test/[[escapedSlot]]}}
+    </p>
   </section>
 </section>

tests/spec/core/xref-spec.js

@@ -756,8 +756,8 @@ describe("Core — xref", () => {
     it("links internalSlots", async () => {
       const body = `
       <section>
-        <p><dfn>[[\\type]]</dfn></p>
-        <p id="link1">{{ [[type]] }}</p>
+        <p><dfn data-dfn-for="Window">[[\\type]]</dfn></p>
+        <p id="link1">{{ Window/[[type]] }}</p>
         <p id="link2">{{ Credential.[[type]] }}</p>
       </section>
       `;