Deprecation: #104789 - Fluid variables true, false, null
See forge#104789
Description
Fluid standalone will add proper language syntax for booleans and null
with Fluid v4, which will be used in TYPO3 v13. Thus, user-defined variables
named true, false and null are no longer allowed.
Impact
Assigning variables with name true, false or null will throw
an exception in Fluid v4. In preparation of this change, Fluid v2.15 logs a
deprecation level error message if any of these variable names are used.
Affected installations
Instances with Fluid templates using true, false or null as user-defined variable names.
This should rarely happen, as it would involve using
$view->assign.
Migration
Template code using these variables should be adjusted to use different variable names. In Fluid v4, the variables will contain their matching PHP counterparts.