SPEL and Enum variable resolution using wrong cachedExecutor [SPR-10452]

[spring-projects-issues]

Martin Frey opened SPR-10452 and commented

The bug is appearing if the Enum used is bound in a variable and the method "values()" is called. I'm currently using Thymeleaf as the templateEngine and I'm not fully certain that this is related. Probably it's possible to reproduce in a plain Java test but i had no time yet.

The screenshot shows the issue.

• MethodReference$MethodValueRef's target is the enum RiskLevel
• The executorToUse is resolved to the Method ActionType.values()

The second screenshot shows the thymeleaf code for the iteration.

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Affects: 3.2.2

Attachments:

• EnumListFrontendCode.jpg (31.42 kB)
• WrongTargetEnumInSPEL322.jpg (219.04 kB)

Issue Links:

• Cached MethodExecutor invokes wrong method [SPR-10657] #15285 Cached MethodExecutor invokes wrong method
• MethodResolver results are cached in SpEL expressions, so changing the context at evaluation time has no effect [SPR-9495] #14129 MethodResolver results are cached in SpEL expressions, so changing the context at evaluation time has no effect

Referenced from: commits 5e6044c, b9d726f

[spring-projects-issues]

Martin Frey commented

Found a way to reproduce it with plain java. (I'm not sure if we are allowed to use EL like this though)

SpelParserConfiguration configuration = new SpelParserConfiguration(false, false);
ExpressionParser parser = new SpelExpressionParser(configuration);

StandardEvaluationContext context = new StandardEvaluationContext();
Expression spel = parser.parseExpression("#enumType.values()");

context.setVariable("enumType", RiskLevel.class);
Object result = spel.getValue(context);

context.setVariable("enumType", ActionType.class);
result = spel.getValue(context);

[spring-projects-issues]

Martin Frey commented

Funny enough the method "getSimpleName()" is resolved properly:

SpelParserConfiguration configuration = new SpelParserConfiguration(false, false);
ExpressionParser parser = new SpelExpressionParser(configuration);

StandardEvaluationContext context = new StandardEvaluationContext();
Expression spelName = parser.parseExpression("#enumType.getSimpleName()");
Expression spelValues = parser.parseExpression("#enumType.values()");

context.setVariable("enumType", RiskLevel.class);
Object name = spelName.getValue(context);
Object values = spelValues.getValue(context);
System.out.println(name + ": " + values);

context.setVariable("enumType", ActionType.class);
name = spelName.getValue(context);
values = spelValues.getValue(context);
System.out.println(name + ": " + values);

--------------------- Results in -----------------
RiskLevel: [Lcom.RiskLevel;@f61730
ActionType: [Lcom.RiskLevel;@6c623e

[spring-projects-issues]

Martin Frey commented

Workaround:

@Component
public class EnumHelper {
public Enum<?>[] values(Class<Enum<?>> enumClass) {
return enumClass.getEnumConstants();
}
}

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Looks like it has to do with the "values()" method beeing a static method. Once the expression has a cachedExecutor for "values()" this one is always referencing the first enum.

[spring-projects-issues]

Juergen Hoeller commented

Indeed, this turns out to be a general problem with EL resolution against static methods. Fixed for 4.0 RC1 and 3.2.5 now.

Juergen