Custom Language's sensor not triggered

Rules and Languages
1

I wanted to add a new custom language check. The language is called Gherkin, whereas the file suffix is .feature. I let Microsoft’s copilot generate some Java classes and a pom, and added some logs.

<project>
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.example</groupId>
	<artifactId>sonar-gherkin-plugin</artifactId>
	<version>1.0.0</version>
    <packaging>sonar-plugin</packaging>
	<dependencies>
		<dependency>
			<groupId>org.sonarsource.api.plugin</groupId>
			<artifactId>sonar-plugin-api</artifactId>
			<version>10.14.0.2599</version>
			<scope>provided</scope>
		</dependency>
	</dependencies>
	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>17</java.version>
		<maven.compiler.encoding>${project.build.sourceEncoding}</maven.compiler.encoding>
		<maven.resources.encoding>${project.build.sourceEncoding}</maven.resources.encoding>
		<maven.compiler.source>${java.version}</maven.compiler.source>
		<maven.compiler.target>${java.version}</maven.compiler.target>
	</properties>
	<build>
		<plugins>
            <plugin>
              <groupId>org.sonarsource.sonar-packaging-maven-plugin</groupId>
              <artifactId>sonar-packaging-maven-plugin</artifactId>
              <version>1.23.0.740</version>
              <extensions>true</extensions>
              <configuration>
                <pluginKey>gherkin-rules</pluginKey>
                <pluginName>Gherkin Rules Plugin</pluginName>
                <pluginClass>com.example.gherkin.GherkinRulesPlugin</pluginClass>
                <pluginDescription>my first attempts to implement Gherkin checks</pluginDescription>
                    <requiredForLanguages>gherkin</requiredForLanguages>
              </configuration>
            </plugin>
		</plugins>
	</build>
</project>

package com.example.gherkin;

import org.sonar.api.resources.Language;

public class GherkinLanguage implements Language {
    public static final String LANGUAGE_KEY = "gherkin";

    public static final String LANGUAGE_NAME = "Gherkin";

    @Override
    public String getKey() {
        System.out.println("GherkinLanguage.getKey " + LANGUAGE_KEY);
        return LANGUAGE_KEY;
    }

    @Override
    public String getName() {
        System.out.println("GherkinLanguage.getName " + LANGUAGE_NAME);
        return LANGUAGE_NAME;
    }

    @Override
    public String[] getFileSuffixes() {
        System.out.println("GherkinLanguage.getFileSuffixes");
        return new String[]{".feature"};
    }
}

package com.example.gherkin;

import org.sonar.api.server.profile.BuiltInQualityProfilesDefinition;

public class GherkinQualityProfile implements BuiltInQualityProfilesDefinition {
    @Override
    public void define(Context context) {
        System.out.println(">GherkinQualityProfile define");
        NewBuiltInQualityProfile profile = context
                .createBuiltInQualityProfile("Gherkin Way", GherkinLanguage.LANGUAGE_KEY);
        profile.setDefault(true);
        profile.activateRule("gherkin-rules", "scenario-case");
        profile.done();
        System.out.println("<GherkinQualityProfile define");
    }
}

package com.example.gherkin;

import org.sonar.api.Plugin;

public class GherkinRulesPlugin implements Plugin {
    @Override
    public void define(Context context) {
        System.out.println(">GherkinRulesPlugin.define");
        context.addExtensions(
                GherkinLanguage.class,
                ScenarioCaseCheck.class,
                GherkinQualityProfile.class,
                GherkinSensor.class);
        System.out.println("<GherkinRulesPlugin.define");
    }
}

package com.example.gherkin;

import org.sonar.api.batch.fs.FileSystem;
import org.sonar.api.batch.fs.InputFile;
import org.sonar.api.batch.sensor.Sensor;
import org.sonar.api.batch.sensor.SensorContext;
import org.sonar.api.batch.sensor.SensorDescriptor;
import org.sonar.api.batch.sensor.issue.NewIssue;

import java.io.IOException;
import java.util.List;
import java.util.SortedSet;

public class GherkinSensor implements Sensor {

    private static final String SCENARIO_KEY = "Scenario:";

    private static final int SCENARIO_KEY_LENGTH = SCENARIO_KEY.length();

    @Override
    public void describe(SensorDescriptor sensorDescriptor) {
        System.out.println(">GherkinSensor.describe");
        sensorDescriptor
                .name("Gherkin Sensor")
                .onlyOnLanguage(GherkinLanguage.LANGUAGE_KEY)
                .onlyOnFileType(InputFile.Type.MAIN)
                .createIssuesForRuleRepository(GherkinLanguage.LANGUAGE_KEY + "-Scenario");
        System.out.println("<GherkinSensor.describe");
    }

    @Override
    public void execute(SensorContext context) {
        System.out.println(">GherkinSensor.execute");
        FileSystem fs = context.fileSystem();
        SortedSet<String> languages = fs.languages();
        for (String language : languages) {
            System.out.println("Gherkin: " + language);
        }
        System.out.println(String.format("Gherkin start to scan file system %s", fs));
        Iterable<InputFile> featureFiles = fs.inputFiles(fs.predicates().hasLanguage(GherkinLanguage.LANGUAGE_KEY));

        for (InputFile inputFile : featureFiles) {
            System.out.println(String.format("scanning %s", inputFile.filename()));
            try {
                List<String> lines = inputFile.contents().lines().toList();
                for (String line : lines) {
                    String trimmed = line.trim();
                    if (trimmed.startsWith(SCENARIO_KEY)) {
                        String scenarioText = trimmed.substring(SCENARIO_KEY_LENGTH).trim();
                        if (!scenarioText.isEmpty() && !Character.isUpperCase(scenarioText.charAt(0))) {
                            System.out.println(scenarioText);
                            NewIssue issue = context.newIssue()
                                    .forRule(ScenarioCaseCheck.RULE_KEY)
                                    // .at(inputFile.newPointer(i + 1, 0))
                                    ;
                            issue.save();
                        }
                    }
                }
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        System.out.println("<GherkinSensor.execute");
    }
}

package com.example.gherkin;

import org.sonar.api.rule.RuleKey;
import org.sonar.api.server.rule.RulesDefinition;

public class ScenarioCaseCheck implements RulesDefinition {

    public static final RuleKey RULE_KEY = RuleKey.of("gherkin-rules", "scenario-case");

    @Override
    public void define(Context context) {
        System.out.println(">GherkinRulesPlugin.define");
        NewRepository repo = context
                .createRepository(RULE_KEY.repository(), GherkinLanguage.LANGUAGE_KEY)
                .setName("Gherkin Rules");

        repo.createRule(RULE_KEY.rule())
                .setName("Scenario must start with capital letter")
                .setHtmlDescription("Scenarios should begin with a capital letter to maintain readability.");

        repo.done();
        System.out.println("<GherkinRulesPlugin.define");
    }
}

I could create the jar and deploy it into the SonarQube server. When I started it, the log showed only that gherkinRulesPlugin.define was invoked three times and gherkinLanguage.getKey many times and GherkinLanguage.getName some times. In the global configuration of Sonar, I also added the file pattern **/*.feature to be analyzed.

I then added the Quality profile to one of my projects. For that project, I started mvn sonar:sonar. In the server log, GherkinLanguage.getKey was invoked quite some times. But the new language was not checked at all. The log of the mvn command is this:

[INFO] --- sonar:3.10.0.2594:sonar (default-cli) @ star-en-ex ---
[INFO] User cache: C:\Users\C33016\.sonar\cache
[INFO] SonarQube version: 25.4.0.105899
[INFO] Default locale: "de_DE", source code encoding: "UTF-8"
[INFO] Load global settings
[INFO] Load global settings (done) | time=392ms
[INFO] Server id: 63D9CE3B-AYpFXXY47thQMFK43cPX
[INFO] Loading required plugins
[INFO] Load plugins index
[INFO] Load plugins index (done) | time=299ms
[INFO] Load/download plugins
[INFO] Load/download plugins (done) | time=93ms
[INFO] Process project properties
[INFO] Process project properties (done) | time=61ms
[INFO] Project key: starenex
[INFO] Base dir: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
[INFO] Working dir: xxxxxxxxxxxxxxxxxxxxx
[INFO] Load project settings for component key: 'starenex'
[INFO] Load project settings for component key: 'starenex' (done) | time=246ms
[INFO] Load quality profiles
[INFO] Load quality profiles (done) | time=293ms
[INFO] Load active rules
[INFO] Load active rules (done) | time=740ms
[INFO] Load analysis cache
[INFO] Load analysis cache (5.3 kB) | time=178ms
[INFO] Preprocessing files...
[INFO] 2 languages detected in 121 preprocessed files
[INFO] 0 files ignored because of inclusion/exclusion patterns
[INFO] 0 files ignored because of scm ignore settings
[INFO] Loading plugins for detected languages
[INFO] Load/download plugins
[INFO] Load/download plugins (done) | time=113ms
[INFO] Load project repositories
[INFO] Load project repositories (done) | time=575ms
[INFO] Indexing files...
[INFO] Project configuration:
[INFO]   Included sources: **/*.java, **/*.xml, **/*.feature
[INFO]   Excluded sources for coverage: **/**
[INFO] 121 files indexed
[INFO] Quality profile for java: Eon Test Automation
[INFO] Quality profile for xml: Sonar way
[INFO] ------------- Run sensors on module Star EnEx
[INFO] Load metrics repository
[INFO] Load metrics repository (done) | time=60ms
[INFO] Sensor JavaSensor [java]
[INFO] Configured Java source version (sonar.java.source): 17, preview features enabled (sonar.java.enablePreview): false
[INFO] Server-side caching is enabled. The Java analyzer will not try to leverage data from a previous analysis.
[INFO] Using ECJ batch to parse 85 Main java source files with batch size 426 KB.
[INFO] Starting batch processing.
[INFO] The Java analyzer cannot skip unchanged files in this context. A full analysis is performed for all files.
[INFO] 58% analyzed
[WARNING] import for com.eon.star.framework.entity.playwright.PlaywrightContextHolder found
[INFO] field powercloudLoginViaSteps of class StartSessionSteps skipped because type PowercloudLoginViaSteps in exclusions
[INFO] 100% analyzed
[INFO] Batch processing: Done.
[INFO] Did not optimize analysis for any files, performed a full analysis for all 85 files.
[INFO] Using ECJ batch to parse 35 Test java source files with batch size 426 KB.
[INFO] Starting batch processing.
[INFO] 100% analyzed
[INFO] Batch processing: Done.
[INFO] Did not optimize analysis for any files, performed a full analysis for all 35 files.
[INFO] No "Generated" source files to scan.
[INFO] Sensor JavaSensor [java] (done) | time=23441ms
[INFO] Sensor SurefireSensor [java]
[INFO] parsing [C:\Users\C33016\IdeaProjects\star-en-ex\target\surefire-reports]
[INFO] Sensor SurefireSensor [java] (done) | time=226ms
[INFO] Sensor XML Sensor [xml]
[INFO] 1 source file to be analyzed
[INFO] 1/1 source file has been analyzed
[INFO] Sensor XML Sensor [xml] (done) | time=270ms
[INFO] Sensor JaCoCo XML Report Importer [jacoco]
[INFO] 'sonar.coverage.jacoco.xmlReportPaths' is not defined. Using default locations: target/site/jacoco/jacoco.xml,target/site/jacoco-it/jacoco.xml,build/reports/jacoco/test/jacocoTestReport.xml
[INFO] No report imported, no coverage information will be imported by JaCoCo XML Report Importer
[INFO] Sensor JaCoCo XML Report Importer [jacoco] (done) | time=6ms
[INFO] Sensor Java Config Sensor [iac]
[INFO] 0 source files to be analyzed
[INFO] 0/0 source files have been analyzed
[INFO] Sensor Java Config Sensor [iac] (done) | time=41ms
[INFO] Sensor IaC Docker Sensor [iac]
[INFO] 0 source files to be analyzed
[INFO] 0/0 source files have been analyzed
[INFO] Sensor IaC Docker Sensor [iac] (done) | time=144ms
[INFO] Sensor TextAndSecretsSensor [text]
[INFO] Available processors: 12
[INFO] Using 12 threads for analysis.
[INFO] Using git CLI to retrieve untracked files
[INFO] Analyzing language associated files and files included via "sonar.text.inclusions" that are tracked by git
[INFO] 121 source files to be analyzed
[INFO] 121/121 source files have been analyzed
[INFO] Sensor TextAndSecretsSensor [text] (done) | time=1805ms
[INFO] ------------- Run sensors on project
[INFO] Sensor Zero Coverage Sensor
[INFO] Sensor Zero Coverage Sensor (done) | time=5ms
[INFO] Sensor Java CPD Block Indexer
[INFO] Sensor Java CPD Block Indexer (done) | time=161ms
[INFO] ------------- Gather SCA dependencies on project
[INFO] Dependency analysis skipped
[INFO] CPD Executor 11 files had no CPD blocks
[INFO] CPD Executor Calculating CPD for 74 files
[INFO] CPD Executor CPD calculation finished (done) | time=85ms
[INFO] SCM revision ID '869af4d2b5daaf0f29de42103a16dee0b05119dc'
[INFO] Analysis report generated in 430ms, dir size=773.6 kB
[INFO] Analysis report compressed in 997ms, zip size=335.8 kB
[INFO] Analysis report uploaded in 353ms
[INFO] ------------- Check Quality Gate status
[INFO] Waiting for the analysis report to be processed (max 300s)
[INFO] QUALITY GATE STATUS: PASSED - View details on http://localhost:9100/dashboard?id=starenex
[INFO] Analysis total time: 56.123 s
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  01:12 min
[INFO] Finished at: 2025-07-10T08:52:09+02:00
[INFO] ------------------------------------------------------------------------

What I don’t understand: why is the gherkin sensor not invoked at all, and why does the log tell “2 languages detected…” and not 3?

2

Hello,

Have you checked out SonarQube’s custom plugin example? Modeling your implementation after this example might be more effective than relying solely on Copilot for guidance.

3

I built the custom plugin example, and it showed the same effects: the Sensors are not invoked. And mvn sonar:sonar responds that it only discovered 2 languages: java and xml. But it did not mention foo what I would have expected with the Sonar example

4

Of course, I have added Foo quality profile to my project

5

eventually, I got the foo example running by adding the **/*.foo to the global administration for the file extensions to be checked. That is a good starting point, and I’ll try my own things from that. Many thanks for your hint

6

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