palantir / palantir/palantir-java-format

Incorrectly removes java.lang import that disambiguates an import or same-package class

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Java
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Description

Version: 2.68.0

Consider the following set up

// example/src/main/java/com/company/project/foo/Byte.java
package com.company.project.foo;

public class Byte {

}

// example/src/main/java/com/company/project/bar/Test.java
package com.company.project.bar;

import com.company.project.foo.*;

import java.lang.Byte;

public class Test {
    public Byte foo() {
        // ...
    }
}

Assume there are other relevant classes under src/main/java/com/company/project/foo.

When running palantir-java-format on Test.java, the java.lang.Byte is removed. However, this is incorrect, as it was used to disambiguate com.company.project.foo.Bar. This ends up leading to a compilation failure as we use the wrong Byte class.


Or more generally, if Byte was in the same package, and there was no other import:

// example/src/main/java/com/company/project/bar/Byte.java
package com.company.project.bar;

public class Byte {

}

// example/src/main/java/com/company/project/bar/Test.java
package com.company.project.bar;

import java.lang.Byte;

public class Test {
    public Byte foo() {
        // ...
    }
}

The java.lang.Byte import is still removed. This one is not as easy to workaround compared to the former (where we could've just expanded the wildcard imports)

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the formatter behavior with the example/src/main/java/com/company/project/foo/Byte.java, bar/Byte.java, and bar/Test.java examples, starting with the import handling for java.lang.Byte. Done means formatting no longer removes the explicit import when it disambiguates a wildcard-imported or same-package class, avoiding the reported compilation failure.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
tooling
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
48/100

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