fix(canvas): default malformed host base paths

steipete · steipete · commit e9d49299d67e · 2026-05-29T01:34:30.000-04:00
diff --git a/extensions/canvas/src/host/server.test.ts b/extensions/canvas/src/host/server.test.ts
@@ -217,6 +217,20 @@ describe("canvas host", () => {
     }
   });
 
+  it("falls back to the default mount when the configured base path is malformed", async () => {
+    const dir = await createCaseDir();
+    await fs.writeFile(path.join(dir, "index.html"), "<html><body>fallback</body></html>", "utf8");
+    const handler = await createTestCanvasHostHandler(dir, { basePath: "/%E0%A4%A" });
+
+    try {
+      const response = await captureHandlerResponse(handler, `${CANVAS_HOST_PATH}/`);
+      expect(response.status).toBe(200);
+      expect(response.body).toContain("fallback");
+    } finally {
+      await handler.close();
+    }
+  });
+
   it("serves canvas content from the mounted base path and reuses handlers without double close", async () => {
     const dir = await createCaseDir();
     await fs.writeFile(path.join(dir, "index.html"), "<html><body>v1</body></html>", "utf8");
diff --git a/extensions/canvas/src/host/server.ts b/extensions/canvas/src/host/server.ts
@@ -185,7 +185,12 @@ function isDisabledByEnv() {
 
 function normalizeBasePath(rawPath: string | undefined) {
   const trimmed = (rawPath ?? CANVAS_HOST_PATH).trim();
-  const normalized = normalizeUrlPath(trimmed || CANVAS_HOST_PATH);
+  let normalized: string;
+  try {
+    normalized = normalizeUrlPath(trimmed || CANVAS_HOST_PATH);
+  } catch {
+    normalized = normalizeUrlPath(CANVAS_HOST_PATH);
+  }
   if (normalized === "/") {
     return "/";
   }
