[MC-300950] execute if function inconsistent if the function does not exist

Steps to reproduce:

Run the following with only the vanilla datapack enabled

/execute if function example:example run say true
/execute unless function example:example run say true

Observed behaviour:

In neither case say true is executed

Expected behaviour:

fail is returned therefore the second case should execute say hi

Comments 2

[Mojang] Triage Team 2025-08-14T07:13:30Z

Thank you for your report!
After consideration, the issue is being closed as Working as Intended.

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boq 2025-08-14T08:05:18Z

Both commands actually fail, but error is hidden due to how /execute works (it would be visible with trace command)
In future we are likely to instead make command not compile at all on missing function.