test: build server function only referenced in client code

Author: katywings

apps/tests/src/e2e/server-function.test.ts

@@ -105,4 +105,19 @@ test.describe("server-function", () => {
     await page.goto("http://localhost:3000/server-function-unused-destructure");
     await expect(page.locator("#server-fn-test")).toContainText("false");
   });
+
+  /**
+   * Makes sure that server function dead code elimination
+   * runs before Solid's SSR transforms.
+   *
+   * Solid's SSR code removes client-only event handler code
+   * such as onClick, but server function's only referenced
+   * in such event handlers still must be registered on
+   * the server.
+   */
+  test("should build with a server function only referenced inside onClick", async ({ page }) => {
+    await page.goto("http://localhost:3000/server-function-onclick");
+    await page.locator("#server-fn-test").click();
+    await expect(page.locator("#server-fn-test")).toContainText("false");
+  });
 });

apps/tests/src/routes/server-function-onclick.tsx

@@ -0,0 +1,23 @@
+async function serverFnOnClick() {
+  "use server";
+
+  return false;
+}
+
+export default function App() {
+  return (
+    <main>
+      <span
+        id="server-fn-test"
+        onClick={evt => {
+          const el = evt.target;
+          serverFnOnClick().then(r => {
+            el.textContent = JSON.stringify(r);
+          });
+        }}
+      >
+        Click me
+      </span>
+    </main>
+  );
+}