addressing codex review

pgondhi987 · pgondhi987 · commit be904b6fa8eb · 2026-05-14T18:22:27.000Z
diff --git a/extensions/canvas/src/cli-helpers.test.ts b/extensions/canvas/src/cli-helpers.test.ts
@@ -19,6 +19,15 @@ describe("canvas CLI helpers", () => {
     );
   });
 
+  it.each([{ base64: "aGk=" }, { format: 42, base64: "aGk=" }])(
+    "rejects invalid canvas.snapshot format fields",
+    (payload) => {
+      expect(() => parseCanvasSnapshotPayload(payload)).toThrow(
+        /invalid canvas\.snapshot payload/i,
+      );
+    },
+  );
+
   it.each(["/../../target.sh", "../target.sh", "png/../../target.sh", "image/png", ""])(
     "rejects unsafe canvas.snapshot formats from responses: %s",
     (format) => {
diff --git a/extensions/canvas/src/cli-helpers.ts b/extensions/canvas/src/cli-helpers.ts
@@ -12,8 +12,8 @@ type CanvasSnapshotPayload = {
 type CanvasSnapshotFormat = "png" | "jpg" | "jpeg";
 type CanvasSnapshotFileExtension = "png" | "jpg";
 
-function normalizeCanvasSnapshotFormat(value: string): CanvasSnapshotFormat | null {
-  const format = value.trim().toLowerCase();
+function normalizeCanvasSnapshotFormat(value: string | undefined): CanvasSnapshotFormat | null {
+  const format = value?.trim().toLowerCase() ?? "";
   if (format === "png" || format === "jpg" || format === "jpeg") {
     return format;
   }
