Fix stale presenter after expected operation errors

src/core/Recipe.mjs

@@ -241,9 +241,11 @@ class Recipe  {
                     // Cannot rely on `err instanceof OperationError` here as extending
                     // native types is not fully supported yet.
                     dish.set(err.message, "string");
+                    this.lastRunOp = null;
                     return i;
                 } else if (err instanceof DishError || err?.type === "DishError") {
                     dish.set(err.message, "string");
+                    this.lastRunOp = null;
                     return i;
                 } else {
                     const e = typeof err == "string" ? { message: err } : err;

tests/operations/tests/RenderPDF.mjs

@@ -7,6 +7,9 @@
 import TestRegister from "../../lib/TestRegister.mjs";
 
 
+const oversizedPdfLikeInput = "%PDF-1.0\n" + "A".repeat(5000);
+
+
 TestRegister.addTests([
     {
         name: "RenderPDF",
@@ -34,4 +37,34 @@ TestRegister.addTests([
             }
         ],
     },
+    {
+        name: "RenderPDF followed by Generate QR Code error returns plain text",
+        input: oversizedPdfLikeInput,
+        expectedMatch: /^Error generating QR code\. \(/,
+        recipeConfig: [
+            {
+                "op": "Render PDF",
+                "args": ["Raw"]
+            },
+            {
+                "op": "Generate QR Code",
+                "args": ["PNG", 1, 0, "High"]
+            }
+        ],
+    },
+    {
+        name: "RenderPDF followed by Generate QR Code error does not render iframe",
+        input: oversizedPdfLikeInput,
+        unexpectedMatch: /<iframe/i,
+        recipeConfig: [
+            {
+                "op": "Render PDF",
+                "args": ["Raw"]
+            },
+            {
+                "op": "Generate QR Code",
+                "args": ["PNG", 1, 0, "High"]
+            }
+        ],
+    },
 ]);