Add Jar overlap test

samples/sample-all-deactivated/settings.gradle.kts

@@ -9,8 +9,14 @@ pluginManagement {
 
 dependencyResolutionManagement {
     repositories {
-        mavenCentral()
-        maven("https://maven.scijava.org/content/repositories/releases")
-        maven("https://maven.scijava.org/content/groups/public")
+        maven("https://maven.scijava.org/content/groups/public") {
+            mavenContent {
+                includeGroup("org.jzy3d")
+                includeGroup("org.smurn")
+            }
+        }
+        mavenCentral() {
+            metadataSources.artifact() // woodstox/wstx-lgpl/3.2.7
+        }
     }
 }

samples/sample-all/settings.gradle.kts

@@ -9,8 +9,14 @@ pluginManagement {
 
 dependencyResolutionManagement {
     repositories {
-        mavenCentral()
-        maven("https://maven.scijava.org/content/repositories/releases")
-        maven("https://maven.scijava.org/content/groups/public")
+        maven("https://maven.scijava.org/content/groups/public") {
+            mavenContent {
+                includeGroup("org.jzy3d")
+                includeGroup("org.smurn")
+            }
+        }
+        mavenCentral() {
+            metadataSources.artifact() // woodstox/wstx-lgpl/3.2.7
+        }
     }
 }

src/test/groovy/org/gradlex/jvm/dependency/conflict/test/JarOverlapTest.groovy

@@ -0,0 +1,111 @@
+package org.gradlex.jvm.dependency.conflict.test
+
+import org.gradle.testfixtures.ProjectBuilder
+import org.gradlex.jvm.dependency.conflict.detection.rules.CapabilityDefinition
+import spock.lang.Specification
+
+import java.util.zip.ZipFile
+
+import static org.gradlex.jvm.dependency.conflict.detection.rules.CapabilityDefinition.*
+
+/**
+ * Test that checks that the Jar files behind each CapabilityDefinition actually have overlapping classes.
+ */
+class JarOverlapTest extends Specification {
+
+    // Some Jars do not have overlapping classes, but contain conflicting implementations of the same service.
+    static def expectedToOverlap = values() - [
+            SLF4J_VS_JCL, // bridge vs. replacement
+            SLF4J_VS_LOG4J2_FOR_JCL, // SLF4J replaces JCL, while LOG4J depends on JCL
+            SLF4J_IMPL, // register conflicting service implementations
+            SLF4J_VS_LOG4J2_FOR_JUL, // register conflicting handler implementations
+            HAMCREST_CORE, // contains 'IsDeprecated.class' and forwards to HAMCREST
+            HAMCREST_LIBRARY // contains 'IsDeprecated.class' and forwards to HAMCREST
+    ]
+
+    def latestVersions = []
+
+    void setup() {
+        latestVersions = new File("samples/sample-all/build.gradle.kts")
+                .readLines()
+                .findAll { it.contains("implementation(") }
+                .collect { it.trim() }
+                .collect { it.replace("implementation(\"", "") }
+                .collect { it.replace("\")", "") }
+    }
+
+    def "capability definition is valid"(CapabilityDefinition definition) {
+        given:
+        def specificVersions = definitionSpecificVersions(definition)
+        def project = ProjectBuilder.builder().build()
+        def dependencies = project.dependencies
+        project.plugins.apply("jvm-ecosystem")
+        project.repositories.maven {
+            url = "https://maven.scijava.org/content/groups/public"
+            mavenContent { it.includeGroup("org.jzy3d") }
+        }
+        project.repositories.mavenCentral {
+            it.metadataSources.artifact() // woodstox/wstx-lgpl/3.2.7
+            it.metadataSources.ignoreGradleMetadataRedirection()
+        }
+
+        def modules = definition.modules.collect { module ->
+            def specific = specificVersions.find { it.startsWith(module + ":") }
+            if (specific) {
+                dependencies.create(specific)
+            } else {
+                dependencies.create(latestVersions.find { it.startsWith(module + ":") })
+            }
+        }
+
+        def conf = project.getConfigurations().detachedConfiguration(*modules)
+        conf.transitive = false
+
+        when:
+        List<Tuple2<String, Set<String>>> jarClassFiles = conf.files.collect { jar ->
+            def jarName = jar.name
+            new Tuple2(jarName, new ZipFile(jar).withCloseable {
+                it.entries().collect { entry -> entry.name }.findAll { it.endsWith(".class") } as Set
+            })
+        }
+
+        then:
+        [jarClassFiles, jarClassFiles].combinations().each { Tuple2<String, Set<String>> a, Tuple2<String, Set<String>> b ->
+            println("Comparing: ${a.v1} <--> ${b.v1}")
+            assert !a.v2.intersect(b.v2).isEmpty()
+        }
+
+        where:
+        definition << expectedToOverlap
+    }
+
+    private static List<String> definitionSpecificVersions(CapabilityDefinition definition) {
+        switch (definition) {
+            case JAVAX_ACTIVATION_API:
+                return ["jakarta.activation:jakarta.activation-api:1.2.2", "com.sun.activation:jakarta.activation:1.2.2"]
+            case JAVAX_ANNOTATION_API:
+                return ["jakarta.annotation:jakarta.annotation-api:1.3.5", "org.apache.tomcat:tomcat-annotations-api:9.0.104"]
+            case JAVAX_EJB_API:
+                return ["jakarta.ejb:jakarta.ejb-api:3.2.6"]
+            case JAVAX_EL_API:
+                return ["jakarta.el:jakarta.el-api:3.0.3"]
+            case JAVAX_MAIL_API:
+                return ["com.sun.mail:mailapi:1.6.7", "jakarta.mail:jakarta.mail-api:1.6.7", "com.sun.mail:jakarta.mail:1.6.7"]
+            case JAVAX_PERSISTENCE_API:
+                return ["jakarta.persistence:jakarta.persistence-api:2.2.3"]
+            case JAVAX_SERVLET_API:
+                return ["jakarta.servlet:jakarta.servlet-api:4.0.4", "org.apache.tomcat:servlet-api:6.0.53",
+                        "org.apache.tomcat:tomcat-servlet-api:9.0.104", "org.apache.tomcat.embed:tomcat-embed-core:9.0.104"]
+            case JAVAX_TRANSACTION_API:
+                return ["jakarta.transaction:jakarta.transaction-api:1.3.3"]
+            case JAVAX_WEBSOCKET_API_RULE:
+                return ["jakarta.websocket:jakarta.websocket-api:1.1.2", "jakarta.websocket:jakarta.websocket-client-api:1.1.2",
+                        "org.apache.tomcat:tomcat-websocket-api:9.0.104", "org.apache.tomcat:tomcat-websocket:9.0.104",
+                        "org.apache.tomcat.embed:tomcat-embed-websocket:9.0.104"]
+            case JAVAX_WS_RS_API:
+                return ["jakarta.ws.rs:jakarta.ws.rs-api:2.1.6"]
+            default:
+                return []
+        }
+    }
+}