Collection of Checkers for EO Programs

This Java package is a collection of "lints" (aka "checkers") for XMIR (an intermediate representation of a EO object). This is primarily about best practices and readiness of code for successful compilation and execution, not about code formatting. A few lints also enforce naming conventions, since consistent naming is considered a best practice here too.

We use this package as a dependency in the EO-to-Java compiler:

<dependency>
  <groupId>org.eolang</groupId>
  <artifactId>lints</artifactId>
  <version>0.4.1</version>
</dependency>

You can also use it in order to validate the validity of XMIR documents your software may generate:

import com.jcabi.xml.StrictXML;
import org.eolang.lints.Source;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

final class Foo {
    @Test
    void testValidSource() {
        Assertions.assertTrue(
            new Source(
                new StrictXML("<object> your XMIR goes here </object>")
            ).defects().isEmpty()
        );
    }
}

It is possible to disable any particular linter in a program, with the help of the +unlint meta.

Whole-program analysis (running lints across a set of XMIR files instead of one at a time) lives in a separate package, org.eolang:wpa.

Design of This Library

The library is designed as a set of lints, each of which is a separate class implementing the Lint interface. Each lint is responsible for checking one particular aspect of the XMIR document. The Source class is responsible for running all lints and collecting defects for a single XMIR file. All in all, there are only three classes and interfaces that are supposed to be exposed to a user of the library:

• Source - checker of a single XMIR
• Defect - a single defect discovered
• Severity - a severity of a defect

There are also a few classes that implement Iterable<Lint>: PkMono and PkByXsl. They are supposed to be used only by the Source, and are not supposed to be exposed to the user of the library. They are responsible for providing a set of lints to be executed, building them from the information in classpath.

Benchmark

Here is the result of linting XMIRs:

Input: com/sun/jna/PointerType.class (S source)
Lint time: 10s (10054 ms)

Input: com/sun/jna/Memory.class (M source)
Lint time: 7s (7167 ms)

Input: com/sun/jna/Pointer.class (L source)
Lint time: 9s (8715 ms)

Input: com/sun/jna/Structure.class (XL source)
Lint time: 11s (10952 ms)

Input: org/apache/hadoop/hdfs/server/namenode/FSNamesystem.class (XXL source)
Lint time: 38s (37742 ms)



unlint-non-existing-defect (XXL) (14513 ms)
application-without-as-attributes (XXL) (3157 ms)
unlint-non-existing-defect (XL) (2790 ms)
unlint-non-existing-defect (L) (1559 ms)
object-has-data (XXL) (1413 ms)
unlint-non-existing-defect (M) (1256 ms)
empty-object (XXL) (1065 ms)
duplicate-as-attribute (XXL) (797 ms)
redundant-object (XXL) (686 ms)
reserved-name (XXL) (611 ms)
application-without-as-attributes (XL) (597 ms)
line-is-absent (XXL) (569 ms)
incorrect-bytes-format (XXL) (548 ms)
application-without-as-attributes (M) (507 ms)
compound-name (XXL) (469 ms)
bytes-without-data (XXL) (376 ms)

The results were calculated in this GHA job on 2026-07-30 at 05:24, on Linux with 4 CPUs.

How to Contribute

Fork repository, make changes, then send us a pull request. We will review your changes and apply them to the master branch shortly, provided they don't violate our quality standards. To avoid frustration, before sending us your pull request please run full Maven build:

mvn clean install -Pqulice

Also, run this and make sure your changes don't slow us down:

mvn jmh:benchmark

You will need Maven 3.3+ and Java 11+ installed. Also, if you have xcop installed, make sure it is version 0.8.0+. If you want the code to be checked using error-prone, use Java 17+ If you want to check markdown files using vale, just install it and make sure it's in your PATH