Java: Overriding record toString() can't be referred to as a dependency

[rfevang]

Description of the bug:

The compiler complains about an ambiguous reference when trying to refer to an overriden toString() method of a record. The error only happens when the record class is a dependency, not when it is listed in srcs.

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

Empty WORKSPACE. (It also fails when loading rules_java 5.4.0

.bazelrc:

build --java_language_version=17 --java_runtime_version=remotejdk_17
build --tool_java_language_version=17 --tool_java_runtime_version=remotejdk_17

MyRecord.java:

public record MyRecord(String value) {
  public String toString() {
    return "Custom toString(): " + value;
  }
}

DoubleToString.java:

import java.util.function.Supplier;

public class DoubleToString {
  public Supplier<String> foo(MyRecord myRecord) {
    return myRecord::toString;
  }
}

BUILD.bazel:

java_library(
    name = "my_record",
    srcs = ["MyRecord.java"],
)

# Failing rule:
java_library(
    name = "record_to_string_fails",
    srcs = ["DoubleToString.java"],
    deps = [":my_record"],
)

# Working rule:
java_library(
    name = "no_dep_to_string_works",      
    srcs = ["MyRecord.java", "DoubleToString.java"],
)

Doing a bazel build :record_to_string_fails results in the following output:

$ bazel build :record_to_string_fails
INFO: Analyzed target //:record_to_string_fails (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
ERROR: /home/fevang/debug/bazel_bug/BUILD.bazel:6:13: Building librecord_to_string_fails.jar (1 source file) failed: (Exit 1): java failed: error executing command (from target //:record_to_string_fails) external/remotejdk17_linux/bin/java '--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED' '--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED' ... (remaining 16 arguments skipped)
DoubleToString.java:5: error: incompatible types: invalid method reference
    return myRecord::toString;
           ^
    reference to toString is ambiguous
      both method toString() in MyRecord and method toString() in MyRecord match
Target //:record_to_string_fails failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 0.075s, Critical Path: 0.02s
INFO: 2 processes: 2 internal.
FAILED: Build did NOT complete successfully

Building :no_dep_to_string_works works just fine.

Which operating system are you running Bazel on?

Ubuntu 22.04.1 LTS

What is the output of bazel info release?

release 6.0.0

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

No

Any other information, logs, or outputs that you want to share?

Ran into this issue when trying to convert a maven project to bazel.

Building with javac works, even when MyRecord.java is removed after compiling MyRecord.class.

[rfevang]

Similar (probably related) issue involving extra constructors:

MyRecord.java:

public record MyRecord(String value) {

  public MyRecord(String a, String b) {
    this(a + ", " + b);
  }  

  public String toString() {
    return "Custom toString(): " + value;
  }
}

ExtraConstructor.java:

public class ExtraConstructor {
  public void foo() {
    new MyRecord("string");
  }
}

Compiling both in a rule works. If MyRecord is a dependency when compiling ExtraConstructor, the following error is printed:

ExtraConstructor.java:3: error: constructor MyRecord in record MyRecord cannot be applied to given types;
    new MyRecord("string");
    ^
  required: String,String
  found:    String
  reason: actual and formal argument lists differ in length

[rfevang]

Thanks for looking at this @cushon!.

Are there more steps needed? I tried building with HEAD bazel and I still see the same error. Any way I can test this locally?

[cushon]

This will require a java_tools release, I think it's going to be included in bazelbuild/java_tools#60

Until then, testing this requires additional steps: bazelbuild/java_tools#43

[rfevang]

Thanks, I was indeed looking at the outdated documentation on how to run a local java_tools.

Can confirm an updated java_tools fixes the issue in the bug. The related error in my first comment is still there, so opening up a separate issue for that (#17250).

[github-actions]

Thank you for contributing to the Bazel repository! This issue has been marked as stale since it has not had any activity in the last 30 days. It will be closed in the next 7 days unless any other activity occurs or one of the following labels is added: "not stale", "awaiting-bazeler".