Fix stale presenter after expected operation errors

[zainnadeem786]

Summary

Fix an issue where an expected OperationError or DishError could be rendered using a stale presenter from a previously successful operation.

This was reproducible with the following chain:

Render PDF
↓
Generate QR Code (OperationError)

where the expected plain error message was incorrectly returned as an HTML PDF iframe.

Root Cause

Recipe.execute() resets lastRunOp at the beginning of execution and updates it after each successful operation.

When an operation throws an expected OperationError or DishError, the error message is written to the dish as a "string" and execution returns early, but lastRunOp is left unchanged.

Chef.bake() subsequently calls Recipe.present(), which uses the stale presenter from the previous successful operation. As a result, the error string can be wrapped using an unrelated presenter instead of being returned as plain text.

Fix

Clear the presentation state on the expected error paths by resetting lastRunOp before returning.

This keeps the error dish unpresented and allows the plain error message to be returned as intended.

The fix is generic and is applied to both:

• OperationError
• DishError

without introducing any special handling for individual operations.

Regression Tests

Added focused regression coverage for the reported scenario:

• Render PDF followed by Generate QR Code returns a plain QR error message.
• The resulting output does not contain a PDF <iframe>.

Validation

Executed the relevant test suites:

Node API tests:
PASSING 250/250

Operation tests:
PASSING 2051/2051

Impact

• Closes bug(Render PDF, Chained): chaining render pdf with generate qr code will result on html output #2583
• Prevents stale presenters from affecting expected error output.
• Preserves existing presentation behavior for successful operations.
• Provides a generic solution that also covers future presenting operations without additional special cases.

[CLAassistant]

All committers have signed the CLA.

[GCHQDeveloper581]

Looks good!

Thanks for your contribution.

Checked:

• new test fails on previous code
• web gui still correctly indicates which step in the recipe has (first) encountered an error
• recipe still terminates at the filing step
• web gui now renders (error message) correctly for this test case

[zainnadeem786]

@GCHQDeveloper581 Thanks for the review and for improving the tests. I really appreciate the feedback and the collaboration. Looking forward to contributing more!