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Cannot evaluate null-returning expression in DoTag when failOnUnknownTokens is enabled

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
java
Domain
backend

Research direction

Start by reproducing the provided template with failOnUnknownTokens enabled and trace the do tag handling of an expression that evaluates to null. Inspect how unknown-token validation is applied during do tag evaluation; done means the null-returning update expression completes without an UnknownTokenException when no token is missing.

Written by the indexing model from the issue text.

Description

If failOnUnknownTokens option is enabled following code fails with UnknownTokenException:

{% set object = {} %}{% do object.update({}) %}

This always happens if an expression executed by do tag is evaluated to null and failOnUnknown is enabled. Method .update always returns null and there are no missing tokens involved so, logically, I'd expect that to work regardless of the setting

Dominant language
Java
Stars
785
Forks
184
Avg merge
6d 22h
Merged PRs (30d)
1

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