Remove unused imports recipe is removing an used class

[sergiogp98]

Hi,

I am running a single recipe (https://docs.openrewrite.org/recipes/java/removeunusedimports) and is removing some imports of a couple of Java classes which they are already in use, hence it is failing when it tries to compile.

My question: which criteria is used to know if an import is used? I don't understand the explanation in your official documentation:

Remove imports for types that are not referenced. As a precaution against incorrect changes, no imports will be removed from any source where unknown types are referenced.

For example, one of the imports which is removed is this one: org.springframework.security.web.SecurityFilterChain

Thanks.

[timtebeek]

Hi @sergiogp98 ; did you already look at the implementation of the recipe?

rewrite/rewrite-java/src/main/java/org/openrewrite/java/RemoveUnusedImports.java

Lines 55 to 57 in c625f30

	return "Remove imports for types that are not referenced. As a precaution against incorrect changes no imports " +
	"will be removed from any source where unknown types are referenced. The most common cause of unknown " +
	"types is the use of annotation processors not supported by OpenRewrite, such as lombok.";

Roughly speaking we look at the types in use on Lossless Semantic Tree elements in the compilation unit; if such types are missing, then we are at risk of misidentifying a used type as unused. If you have any suggestions for improvement we're more than open to those!

[sergiogp98]

Hi @timtebeek, thanks for the answer. However, I am not very sure how LST works which makes it difficult for me to understand the criteria behind that.
I had to use the whole package name instead of the class name. Instead of having this:

import org.springframework.security.web.SecurityFilterChain;
@Bean    
public SecurityFilterChain webSecurityCustomizer(HttpSecurity http) throws Exception {
      
}

I have to refactor as this:

@Bean
public org.springframework.security.web.SecurityFilterChain webSecurityCustomizer(HttpSecurity http) throws Exception {
  
}

Because line import org.springframework.security.web.SecurityFilterChain is automatically removed by the recipe. Is there a way to prevent that change? I would like the recipe to remove only the unused imports.

[timtebeek]

Hi @sergiogp98 ; sounds like a potential bug with the recipe if that particular import is not retained; would you mind logging that as an issue over on https://github.com/openrewrite/rewrite-spring/issues ?
Indeed we want to keep that import around, but it's not yet clear what causes it to be removed.

[timtebeek]

Might match up with this bug report we got last week:

• RemoveUnusedImports remove used import #3909

[timtebeek]

This has since likely been fixed in

• Fix TypesInUse regression #3914

Thanks for pointing it out!

[sergiogp98]

I have tested and now is not removing that import. Thanks 😄