fix(core): scope getElementById inside compositions

packages/core/src/compiler/compositionScoping.test.ts

@@ -158,6 +158,56 @@ window.__timelines.scene = tl;
     expect(gsapTargets).toEqual([["Scene"], ["Scene"]]);
   });
 
+  it("scopes getElementById when duplicate IDs exist across composition roots", () => {
+    const { document } = parseHTML(`
+      <div data-composition-id="scene-a"><canvas id="gl-canvas"></canvas></div>
+      <div data-composition-id="scene-b"><canvas id="gl-canvas"></canvas></div>
+    `);
+    const fakeWindow = {
+      document,
+      __selectedComp: "",
+      __timelines: {},
+    };
+    const wrapped = wrapScopedCompositionScript(
+      `
+window.__selectedComp =
+  document.getElementById("gl-canvas")
+    ?.closest("[data-composition-id]")
+    ?.getAttribute("data-composition-id") || "null";
+`,
+      "scene-b",
+    );
+
+    new Function("window", wrapped)(fakeWindow);
+
+    expect(fakeWindow.__selectedComp).toBe("scene-b");
+  });
+
+  it("scopes getElementById for IDs that need CSS selector escaping", () => {
+    const { document } = parseHTML(`
+      <div data-composition-id="scene-a"><div id="clip:1"></div></div>
+      <div data-composition-id="scene-b"><div id="clip:1"></div></div>
+    `);
+    const fakeWindow = {
+      document,
+      __selectedComp: "",
+      __timelines: {},
+    };
+    const wrapped = wrapScopedCompositionScript(
+      `
+window.__selectedComp =
+  document.getElementById("clip:1")
+    ?.closest("[data-composition-id]")
+    ?.getAttribute("data-composition-id") || "null";
+`,
+      "scene-b",
+    );
+
+    new Function("window", wrapped)(fakeWindow);
+
+    expect(fakeWindow.__selectedComp).toBe("scene-b");
+  });
+
   it("reads scoped proxy accessors with the original target receiver", () => {
     const root = {
       contains(node: unknown) {

packages/core/src/compiler/compositionScoping.ts

@@ -141,17 +141,30 @@ export function wrapScopedCompositionScript(
     var matches = __hfQueryAll(selector);
     return matches[0] || null;
   };
+  var __hfGetElementById = function(id) {
+    var found = window.document.getElementById(id);
+    if (found && __hfContains(found)) return found;
+    var root = __hfFindRoot();
+    if (!root) return found || null;
+    var idValue = id + "";
+    if (root.id === idValue) return root;
+    if (typeof root.querySelector !== "function") return null;
+    if (typeof CSS !== "undefined" && CSS && typeof CSS.escape === "function") {
+      try {
+        return root.querySelector("#" + CSS.escape(idValue)) || null;
+      } catch {}
+    }
+    try {
+      return root.querySelector('[id="' + __hfEscapeAttr(idValue) + '"]') || null;
+    } catch {}
+    return null;
+  };
   var __hfScopedDocument = typeof Proxy === "function"
     ? new Proxy(window.document, {
         get: function(target, prop, receiver) {
           if (prop === "querySelector") return __hfQueryOne;
           if (prop === "querySelectorAll") return __hfQueryAll;
-          if (prop === "getElementById") {
-            return function(id) {
-              var found = target.getElementById(id);
-              return found && __hfContains(found) ? found : null;
-            };
-          }
+          if (prop === "getElementById") return __hfGetElementById;
           var value = Reflect.get(target, prop, target);
           return typeof value === "function" ? value.bind(target) : value;
         },