Add TCK coverage for Section 1.6 when `expr-a` is the `null` literal (`${null.prop}`, `${null['prop']}`, `${null.method()}`)

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Feature
Clarity
Clearly specified
Activity status
Active
Tech stack
java
Domain
testing

Research direction

Start by locating the TCK tests for Section 1.6 operators [] and . and read nearby cases for null property resolution. Add coverage for ${null.prop}, ${null['prop']}, and ${null.method()} following the issue's stated expected result. Run the relevant TCK tests; done when all three cases pass consistently.

Written by the indexing model from the issue text.

Description

In Section 1.6 ("Operators [] and .") of the Jakarta Expression Language 6.1 specification:

To evaluate expr-a[expr-b] or expr-a[expr-b](params):

  • Evaluate expr-a into value-a.
  • If value-a is null:
    • If expr-a[expr-b] is the last property being resolved:
      • If the expression is a value expression and ValueExpression.getValue(context) was called to initiate this expression evaluation, return null.
      • Otherwise, throw PropertyNotFoundException. [trying to de-reference null for an lvalue]
    • Otherwise, return null.

Section 1.6 makes no distinction between expr-a evaluating to null via an identifier/property (e.g. ${person.nullAddress.street}) versus expr-a being the null literal itself (e.g. ${null.prop}, ${null['prop']}, or ${null.method()}).
However, because the TCK currently only tests value-a == null when resolved from a bean/variable and does not test a literal null base, implementations behave differently:

  • Eclipse Expressly: Returns null (conforming to Section 1.6).
  • Apache Tomcat Jasper EL: Throws jakarta.el.PropertyNotFoundException: ELResolver did not handle type: [null] with property of [null].
Steps to Reproduce
import jakarta.el.ELProcessor;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertNull;
public class NullLiteralBaseTest {
    @Test
    void testNullLiteralPropertyAndMethod() {
        ELProcessor processor = new ELProcessor();
        // Expressly returns null; Jasper EL throws PropertyNotFoundException
        assertNull(processor.eval("null.prop"));
        assertNull(processor.eval("null['prop']"));
        assertNull(processor.eval("null.method()"));
    }
}
Request

Please add TCK tests for ${null.prop}, ${null['prop']}, and ${null.method()} to ensure all certified implementations consistently follow Section 1.6 when expr-a is a null literal.

Dominant language
Java
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Forks
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Avg merge
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Merged PRs (30d)
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  4. Open a pull request that references the issue number.

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