Passing single null value in varargs SpEL expression results in NullPointerException

[richardnewtonoa]

Affected Version : 5.3.13

Worked in version : 5.3.6 (5.3.7 -> 5.3.12 not tested)

Using a Spring expression (for caching annotations) started failing for us when moving to Spring 5.3.13 from 5.3.6.

I have created a jUnit Java class test to replicate the issue
SpelEvaluation.zip
.

[jhoeller]

@sbrannen could this be a side effect of #27582?

[richardnewtonoa]

SpelEvaluation.zip
Updated the test case very slightly ... the expression results are not relevant ... the exception thrown in certain cases is the issue (at least for us)

[sbrannen]

@sbrannen could this be a side effect of #27582?

Yes, that looks like it's probably a regression with regard to null handling.

[sbrannen]

I believe the following change (argument != null &&) in ReflectionHelper.convertArguments(...) might fix the regression, but I'd need to verify what the exact behavior was for null values before the regression.

// If the argument is null or if the argument type is equal to the varargs element
// type, there is no need to convert it or wrap it in an array. For example, using
// StringToArrayConverter to convert a String containing a comma would result in the
// String being split and repackaged in an array when it should be used as-is.
if (argument != null && !sourceType.equals(targetType.getElementTypeDescriptor())) {
	arguments[varargsPosition] = converter.convertValue(argument, sourceType, targetType);
}