SpEL Compiler produces incompatible code with method generic returns [SPR-12040]

[spring-projects-issues]

Artem Bilan opened SPR-12040 and commented

The simple test-case to reproduce:

@Test
public void testSpelCompiler () {
   SpelParserConfiguration configuration =
         new SpelParserConfiguration(SpelCompilerMode.IMMEDIATE, this.getClass().getClassLoader());

   Expression expression = new SpelExpressionParser(configuration)
         .parseExpression("payload / 2");

   expression.getValue(new GenericMessage<Integer>(4));
   expression.getValue(new GenericMessage<Integer>(6));

}

---

Affects: 4.1 RC1

Referenced from: commits 59080ff

[spring-projects-issues]

Andy Clement commented

In fact what should have happened here is the 'isCompilable()' check should have failed and it should not have generated a compilable version! But that isn't so helpful if we want to use the compiler with this kind of expression and it is a common occurrence in Spring Integration. So I have enhanced the compilation to do a bit of extra work when it sees methods like this (in this case the accessor returning the payload apparently returns 'Object') - the compiler will look at the runtime type that actually came back in these situations.

This impacts all the operators involving numerics, so I've fixed it for all the mathematical ones and the relational ones (<, >, etc).

[spring-projects-issues]

Artem Bilan commented

Thanks, Andy!

This issue is fixed: can be closed