Skip wrapper-primitive in `UseAssertSame`; rewrite via `AssertTrueComparisonToAssertEquals` by motlin · Pull Request #995 · openrewrite/rewrite-testing-frameworks

motlin · 2026-05-07T16:54:12Z

What's changed?

For an input like:

Map<String, Double> map = new HashMap<>();
double primitive = 0.5;
assertTrue(map.get("k") == primitive);

UseAssertSame was rewriting it to:

assertSame(map.get("k"), primitive);

It should rewrite to:

assertEquals(map.get("k"), primitive);

To get there:

UseAssertSame now skips when either operand is a Java primitive (with Null and String carved out, since OpenRewrite encodes both as JavaType.Primitive enum values but their == is reference equality).
AssertTrueComparisonToAssertEquals now also accepts mixed primitive-wrapper operands. Wrapper-wrapper is still rejected.

What's your motivation?

PR Skip primitive comparisons in UseAssertSame #992 added a primitive-primitive skip to UseAssertSame, which catches assertTrue(123L == 123).

The rewritten assertSame fails at runtime because Java's == unboxes, but assertSame autoboxes the primitive into a fresh wrapper and compares by reference:

expected: java.lang.Double@4130a648<0.5>
but was:  java.lang.Double@61ff6a49<0.5>

Anything in particular you'd like reviewers to focus on?

Wrapper-wrapper is left to UseAssertSame rather than swept into AssertTrueComparisonToAssertEquals, since rewriting Double == Double to value equality would silently change semantics on intentional reference checks.

Anyone you would like to review specifically?

Checklist

I've added unit tests to cover both positive and negative cases
I've read and applied the recipe conventions and best practices
I've used the IntelliJ IDEA auto-formatter on affected files

…parisonToAssertEquals` `UseAssertSame` was rewriting `assertTrue(wrapper == primitive)` to `assertSame(wrapper, primitive)`, which fails: Java unboxes for `==`, but `assertSame` autoboxes the primitive into a new wrapper and compares by reference. Closes the gap left by openrewrite#992 (primitive-primitive only) by also handling the mixed wrapper-primitive form, with `AssertTrueComparisonToAssertEquals` extended to accept it.

timtebeek

Thanks a lot! More comprehensive than the previous attempt indeed.

moderne-meeseeks Bot added this to OpenRewrite May 7, 2026

moderne-meeseeks Bot assigned motlin May 7, 2026

github-project-automation Bot moved this to In Progress in OpenRewrite May 7, 2026

timtebeek approved these changes May 8, 2026

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github-project-automation Bot moved this from In Progress to Ready to Review in OpenRewrite May 8, 2026

timtebeek merged commit 9434322 into openrewrite:main May 8, 2026
1 check passed

github-project-automation Bot moved this from Ready to Review to Done in OpenRewrite May 8, 2026

motlin deleted the use-assert-same-skip-wrapper-primitive branch May 9, 2026 13:25

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Skip wrapper-primitive in `UseAssertSame`; rewrite via `AssertTrueComparisonToAssertEquals`#995

Skip wrapper-primitive in `UseAssertSame`; rewrite via `AssertTrueComparisonToAssertEquals`#995
timtebeek merged 1 commit into
openrewrite:mainfrom
motlin:use-assert-same-skip-wrapper-primitive

motlin commented May 7, 2026 •

edited by moderne-meeseeks Bot

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motlin commented May 7, 2026 • edited by moderne-meeseeks Bot Loading Uh oh! There was an error while loading. Please reload this page.

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What's changed?

What's your motivation?

Anything in particular you'd like reviewers to focus on?

Anyone you would like to review specifically?

Checklist

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timtebeek left a comment

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motlin commented May 7, 2026 •

edited by moderne-meeseeks Bot

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