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fix: retain doNothing() stubs inside lambda bodies to prevent uncompilable code#1009

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timtebeek merged 6 commits into
openrewrite:mainfrom
darrencilia:fix/fix-retain-doNothing()-stubs-inside-lambda-bodies-to-avoid-uncompilable-lambda
May 28, 2026
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fix: retain doNothing() stubs inside lambda bodies to prevent uncompilable code#1009
timtebeek merged 6 commits into
openrewrite:mainfrom
darrencilia:fix/fix-retain-doNothing()-stubs-inside-lambda-bodies-to-avoid-uncompilable-lambda

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@darrencilia

@darrencilia darrencilia commented May 28, 2026 •
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What's changed?

Added a guard in RemoveDoNothingForDefaultMocks to skip removal of doNothing() stubs when they appear as an expression lambda body or a switch expression arm, preventing a dangling -> which does not compile.

Block lambda and switch block arm cases are not guarded as removal leaves an empty block which is valid Java and can be cleaned up downstream by static analysis.

What's your motivation?

Fixes #1008

When doNothing().when(mock).method(args) is the expression body of a lambda or
a switch expression arm, removing it leaves a dangling -> which does not compile.

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

The two helpers isExpressionLambdaBody() and isSwitchExpressionArm() confirming the cursor level is correct for each case.

Have you considered any alternatives or workarounds?

An alternative would be to remove the entire enclosing construct when the body becomes empty. However this is a significantly more complex AST transformation and risks unintended behaviour changes. Retaining is the safer option for compile-breaking cases.

Any additional context

The bug surfaces through any recipe that chains through RemoveDoNothingForDefaultMocks, including UpgradeSpringBoot_3_5 and all other composite recipes that include RemoveDoNothingForDefaultMocks as part of their stack.

@github-project-automation github-project-automation Bot moved this to In Progress in OpenRewrite May 28, 2026
@darrencilia darrencilia marked this pull request as draft May 28, 2026 20:51
@timtebeek timtebeek self-requested a review May 28, 2026 21:14
@darrencilia
fix: retain doNothing() stubs in expression lambda and switch express…
4887eb9 
…ion arms to prevent uncompilable code
@darrencilia
Merge remote-tracking branch 'origin/fix/fix-retain-doNothing()-stubs…
2494f79 
…-inside-lambda-bodies-to-avoid-uncompilable-lambda' into fix/fix-retain-doNothing()-stubs-inside-lambda-bodies-to-avoid-uncompilable-lambda
@darrencilia

darrencilia commented May 28, 2026 •
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I have updated the oriignal comment and Issue to include my latest commit changes.

For this I added 6 tests:

  • retainsDoNothingInsideLambdaBody - expression lambda, recipe makes no change
  • removesDoNothingInLambdaBlockLeavingEmptyBlock - block lambda sole statement, recipe removes and leaves empty block
  • removesDoNothingWhenNotSoleStatementInLambdaBlock - block lambda multiple statements, recipe removes correctly
  • retainsDoNothingInSwitchExpressionArm - switch arrow arm, recipe makes no change
  • removesDoNothingInSwitchExpressionArmBlockLeavingEmptyBlock - switch block arm sole statement, recipe removes and leaves empty block
  • removesDoNothingWhenNotSoleStatementInSwitchExpressionArmBlock - switch block arm multiple statements, recipe removes correctly

timtebeek
timtebeek reviewed May 28, 2026
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Comment thread src/main/java/org/openrewrite/java/testing/mockito/RemoveDoNothingForDefaultMocks.java Outdated
darrencilia and others added 2 commits May 29, 2026 00:00
@darrencilia @timtebeek
Update src/main/java/org/openrewrite/java/testing/mockito/RemoveDoNot…
82b4ed5 
…hingForDefaultMocks.java

Co-authored-by: Tim te Beek <timtebeek@gmail.com>
@timtebeek
Inline parent-cursor checks and drop redundant null guard
ca6ea38 
Folds isExpressionLambdaBody()/isSwitchExpressionArm() into the single call site and removes the unnecessary mi != null check.
timtebeek
timtebeek approved these changes May 28, 2026
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Thanks again for the help here and the clear test examples. I've inline the small methods just to have fewer indirections when reading the code. We'll merge as soon as CI is green.

@github-project-automation github-project-automation Bot moved this from In Progress to Ready to Review in OpenRewrite May 28, 2026
@timtebeek timtebeek marked this pull request as ready for review May 28, 2026 22:18
@timtebeek timtebeek merged commit 86f2308 into openrewrite:main May 28, 2026
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@github-project-automation github-project-automation Bot moved this from Ready to Review to Done in OpenRewrite May 28, 2026
@darrencilia darrencilia deleted the fix/fix-retain-doNothing()-stubs-inside-lambda-bodies-to-avoid-uncompilable-lambda branch May 28, 2026 22:28
mergify Bot added a commit to robfrank/linklift that referenced this pull request Jun 4, 2026
@mergify
chore(deps): bump org.openrewrite.recipe:rewrite-testing-frameworks f…
106c7a1 
…rom 3.35.2 to 3.37.0 [skip ci]

Bumps [org.openrewrite.recipe:rewrite-testing-frameworks](https://github.com/openrewrite/rewrite-testing-frameworks) from 3.35.2 to 3.37.0.
Release notes

*Sourced from [org.openrewrite.recipe:rewrite-testing-frameworks's releases](https://github.com/openrewrite/rewrite-testing-frameworks/releases).*

> 3.37.0
> ------
>
> What's Changed
> --------------
>
> * Reuse `MockedStatic` for consecutive stubbings of the same class by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#1005](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1005)
> * Add RemoveJupiterMigrationSupport recipe by [`@​sullis`](https://github.com/sullis) in [openrewrite/rewrite-testing-frameworks#1006](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1006)
> * Regenerate recipes.csv by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#1007](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1007)
> * fix: retain doNothing() stubs inside lambda bodies to prevent uncompilable code by [`@​darrencilia`](https://github.com/darrencilia) in [openrewrite/rewrite-testing-frameworks#1009](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1009)
> * Migrate deprecated AssertionsForClassTypes/InterfaceTypes to Assertions by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#1010](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1010)
> * Add direct mockwebserver3 dep when only inherited from parent pom by [`@​steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#1011](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1011)
> * Match MockWebServer.shutdown() against pre-rename type by [`@​steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#1012](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1012)
>
> New Contributors
> ----------------
>
> * [`@​darrencilia`](https://github.com/darrencilia) made their first contribution in [openrewrite/rewrite-testing-frameworks#1009](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1009)
>
> **Full Changelog**: <openrewrite/rewrite-testing-frameworks@v3.36.0...v3.37.0>
>
> 3.36.0
> ------
>
> What's Changed
> --------------
>
> * Skip wrapper-primitive in `UseAssertSame`; rewrite via `AssertTrueComparisonToAssertEquals` by [`@​motlin`](https://github.com/motlin) in [openrewrite/rewrite-testing-frameworks#995](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/995)
> * Add unit test for JUnit6BestPractices by [`@​sullis`](https://github.com/sullis) in [openrewrite/rewrite-testing-frameworks#994](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/994)
> * Cleanup junit vintage engine by [`@​sullis`](https://github.com/sullis) in [openrewrite/rewrite-testing-frameworks#993](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/993)
> * OpenRewrite recipe best practices by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#997](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/997)
> * Fix `JUnit4to5Migration` for classes that extend `org.junit.Assert` by [`@​motlin`](https://github.com/motlin) in [openrewrite/rewrite-testing-frameworks#996](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/996)
> * Preserve newlines when converting `@CsvSource(textBlock = ...)` to `@ValueSource` by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#998](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/998)
> * Fix `EnclosedToNested` failing with "Expected to find enclosing JavaSourceFile" by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#1001](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1001)
> * Fix `assertEquals` delta misinterpreted as message in AssertJ conversion by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#1000](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1000)
> * Add JUnit 6.1 migration recipes by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#1002](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1002)
> * Handle Kotlin sources in `MockitoWhenOnStaticToMockStatic` by [`@​MBoegers`](https://github.com/MBoegers) in [openrewrite/rewrite-testing-frameworks#1003](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/1003)
>
> **Full Changelog**: <openrewrite/rewrite-testing-frameworks@v3.35.3...v3.36.0>
>
> v3.35.3
> -------
>
> What's Changed
> --------------
>
> * OpenRewrite [v8.81.6](https://github.com/openrewrite/rewrite/releases/tag/v8.81.6)
> * Cleanup Mockito AutoCloseable fields by [`@​sullis`](https://github.com/sullis) in [openrewrite/rewrite-testing-frameworks#977](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/977)
> * Preserve mockStatic when returned from helper methods by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#979](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/979)
> * Upgrade junit-bom to 6.x in JUnit 5 to 6 migration by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#978](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/978)
> * Tighten PowerMockitoMockStaticToMockito precondition to actual PowerMockito usage by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#981](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/981)
> * Fix AssertTrueInstanceofToAssertInstanceOf static import by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#984](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/984)
> * Fix `ClassCastException` for `@PrepareForTest(fullyQualifiedNames = "...")` by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#983](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/983)
> * Preserve `doNothing()` stubbings using `ArgumentCaptor.capture()` by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#988](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/988)
> * Document strictness implication of `RemoveInitMocksIfRunnersSpecified` by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#990](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/990)
> * Support `textBlock` attribute in `CsvSourceToValueSource` by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#989](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/989)
> * Skip primitive comparisons in `UseAssertSame` by [`@​timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#992](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/992)
>
> **Full Changelog**: <openrewrite/rewrite-testing-frameworks@v3.35.2...v3.35.3>


Commits

* [`5b719c2`](openrewrite/rewrite-testing-frameworks@5b719c2) Extract documentation examples from tests
* [`1ca6223`](openrewrite/rewrite-testing-frameworks@1ca6223) Match MockWebServer.shutdown() against pre-rename type ([#1012](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/1012))
* [`9479988`](openrewrite/rewrite-testing-frameworks@9479988) Add direct mockwebserver3 dep when only old mockwebserver dep inherited from ...
* [`4d31fbb`](openrewrite/rewrite-testing-frameworks@4d31fbb) Add recipe to migrate AssertionsForClassTypes/InterfaceTypes to Assertions (#...
* [`7cbff2a`](openrewrite/rewrite-testing-frameworks@7cbff2a) OpenRewrite recipe best practices
* [`86f2308`](openrewrite/rewrite-testing-frameworks@86f2308) fix: retain doNothing() stubs inside lambda bodies to prevent uncompilable co...
* [`45d2528`](openrewrite/rewrite-testing-frameworks@45d2528) Update Gradle wrapper 9.5.1
* [`a632e17`](openrewrite/rewrite-testing-frameworks@a632e17) Regenerate recipes.csv ([#1007](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/1007))
* [`0b192ca`](openrewrite/rewrite-testing-frameworks@0b192ca) Add RemoveJupiterMigrationSupport recipe ([#1006](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/1006))
* [`f3f61a6`](openrewrite/rewrite-testing-frameworks@f3f61a6) Reuse `MockedStatic` for consecutive stubbings of the same class ([#1005](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/1005))
* Additional commits viewable in [compare view](openrewrite/rewrite-testing-frameworks@v3.35.2...v3.37.0)
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fix: RemoveDoNothingForDefaultMocks incorrectly removes doNothing() in contexts where removal produces uncompilable code

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