build: fix astro mdx/rehype config + dedupe duplicate ids in dist

astro.config.mjs

@@ -10,41 +10,101 @@ import rehypeAutolinkHeadings from "rehype-autolink-headings";
 import rehypeDetailsSections from "./scripts/rehype-details-sections.mjs";
 import rehypeParagraphIds from "./src/plugins/rehype-paragraph-ids.js";
 
-const must = (name, fn) => {
-  if (typeof fn !== "function") {
-    throw new Error(`[astro.config] rehype plugin "${name}" is not a function (export default vs named?)`);
-  }
-  return fn;
-};
+/**
+ * Cast minimal pour satisfaire @ts-check sans dépendre de types internes Astro/Unified.
+ * @param {unknown} x
+ * @returns {any}
+ */
+const asAny = (x) => /** @type {any} */ (x);
+
+/**
+ * @param {any} node
+ * @param {string} cls
+ * @returns {boolean}
+ */
+function hasClass(node, cls) {
+  const cn = node?.properties?.className;
+  if (Array.isArray(cn)) return cn.includes(cls);
+  if (typeof cn === "string") return cn.split(/\s+/).includes(cls);
+  return false;
+}
+
+/**
+ * Rehype plugin: retire les ids dupliqués en gardant en priorité:
+ * 1) span.details-anchor
+ * 2) h1..h6
+ * 3) sinon: premier rencontré
+ * @returns {(tree: any) => void}
+ */
+function rehypeDedupeIds() {
+  /** @param {any} tree */
+  return (tree) => {
+    /** @type {Map<string, Array<{node:any, pref:number, idx:number}>>} */
+    const occ = new Map();
+    let idx = 0;
+
+    /** @param {any} node */
+    const walk = (node) => {
+      if (!node || typeof node !== "object") return;
+
+      if (node.type === "element") {
+        const id = node.properties?.id;
+        if (typeof id === "string" && id) {
+          let pref = 2;
+          if (node.tagName === "span" && hasClass(node, "details-anchor")) pref = 0;
+          else if (/^h[1-6]$/.test(String(node.tagName || ""))) pref = 1;
+
+          const arr = occ.get(id) || [];
+          arr.push({ node, pref, idx: idx++ });
+          occ.set(id, arr);
+        }
+
+        const children = node.children;
+        if (Array.isArray(children)) for (const c of children) walk(c);
+      } else if (Array.isArray(node.children)) {
+        for (const c of node.children) walk(c);
+      }
+    };
+
+    walk(tree);
+
+    for (const [id, items] of occ.entries()) {
+      if (items.length <= 1) continue;
+
+      items.sort((a, b) => (a.pref - b.pref) || (a.idx - b.idx));
+      const keep = items[0];
+
+      for (let i = 1; i < items.length; i++) {
+        const n = items[i].node;
+        if (n?.properties?.id === id) delete n.properties.id;
+      }
+
+      // safety: on s'assure qu'un seul garde bien l'id
+      if (keep?.node?.properties) keep.node.properties.id = id;
+    }
+  };
+}
 
 export default defineConfig({
   output: "static",
   trailingSlash: "always",
-
   site: process.env.PUBLIC_SITE ?? "http://localhost:4321",
 
   integrations: [
-    mdx(),
+    // Important: MDX hérite du pipeline markdown (ids p-… + autres plugins)
+    mdx({ extendMarkdownConfig: true }),
     sitemap({
       filter: (page) => !page.includes("/api/") && !page.endsWith("/robots.txt"),
     }),
   ],
 
-  // ✅ Plugins appliqués AU MDX
-  mdx: {
-    // ✅ MDX hérite déjà de markdown.rehypePlugins
-    // donc ici on ne met QUE le spécifique MDX
-    rehypePlugins: [
-      must("rehype-details-sections", rehypeDetailsSections),
-    ],
-  },
-
-  // ✅ Plugins appliqués au Markdown non-MDX
   markdown: {
     rehypePlugins: [
-      must("rehype-slug", rehypeSlug),
-      [must("rehype-autolink-headings", rehypeAutolinkHeadings), { behavior: "append" }],
-      must("rehype-paragraph-ids", rehypeParagraphIds),
+      asAny(rehypeSlug),
+      [asAny(rehypeAutolinkHeadings), { behavior: "append" }],
+      asAny(rehypeDetailsSections),
+      asAny(rehypeParagraphIds),
+      asAny(rehypeDedupeIds),
     ],
   },
 });