Tidy up core's build file

build.gradle

@@ -10,7 +10,7 @@ subprojects {
     apply plugin: 'java-library'
     apply plugin: 'idea'
     apply plugin: 'io.franzbecker.gradle-lombok'
-    apply plugin: 'com.github.johnrengelman.shadow'
+    apply from: "$rootDir/gradle/shading.gradle"
 
     group = "org.testcontainers"
 
@@ -99,37 +99,6 @@ subprojects {
         source = delombok.outputs
     }
 
-    shadowJar {
-        configurations = []
-        archiveClassifier.set(null)
-
-        doFirst {
-            // See https://github.com/johnrengelman/shadow/blob/5.0.0/src/main/groovy/com/github/jengelman/gradle/plugins/shadow/tasks/ConfigureShadowRelocation.groovy
-            Set<String> packages = []
-            // Always read from core's configurations
-            for (configuration in tasks.getByPath(":testcontainers:shadowJar").configurations) {
-                for (jar in configuration.files) {
-                    def jf = new java.util.jar.JarFile(jar)
-                    for (entry in jf.entries()) {
-                        def name = entry.name
-                        if (name.endsWith(".class")) {
-                            def index = name.lastIndexOf('/')
-                            if (index != -1) {
-                                packages.add(name.substring(0, index))
-                            }
-                        }
-                    }
-                    jf.close()
-                }
-            }
-            for (pkg in packages) {
-                pkg = pkg.replaceAll('/', '.')
-
-                tasks.shadowJar.relocate(pkg, "org.testcontainers.shaded.${pkg}")
-            }
-        }
-    }
-
     dependencies {
         testImplementation 'ch.qos.logback:logback-classic:1.2.3'
     }

core/build.gradle

@@ -25,8 +25,6 @@ idea.module.testSourceDirs += sourceSets.jarFileTest.allSource.srcDirs
 
 configurations {
     baseline
-    shaded
-    [api, compileOnly, testCompile]*.extendsFrom shaded
 }
 
 shadowJar {
@@ -72,12 +70,6 @@ task japicmp(type: me.champeau.gradle.japicmp.JapicmpTask) {
         "org.testcontainers.shaded.*",
     ]
 
-    classExcludes = []
-
-    methodExcludes = []
-
-    fieldExcludes = []
-
     onlyBinaryIncompatibleModified = true
     htmlOutputFile = file("$buildDir/reports/japi.html")
 }
@@ -99,41 +91,25 @@ dependencies {
         exclude group: "*", module: "*"
     }
 
+    compileOnly 'org.jetbrains:annotations:21.0.1'
+
     api 'junit:junit:4.12'
     api 'org.slf4j:slf4j-api:1.7.30'
-    compileOnly 'org.jetbrains:annotations:21.0.1'
-    testCompileClasspath 'org.jetbrains:annotations:21.0.1'
     api 'org.apache.commons:commons-compress:1.20'
-    api ('org.rnorth.duct-tape:duct-tape:1.0.8') {
-        exclude(group: 'org.jetbrains', module: 'annotations')
-    }
-
-    api "com.github.docker-java:docker-java-api:3.2.11"
-
-    shaded ('com.github.docker-java:docker-java-core:3.2.11') {
-        exclude(group: 'com.github.docker-java', module: 'docker-java-api')
-        exclude(group: 'com.github.docker-java', module: 'docker-java-transport')
-        exclude(group: 'com.fasterxml.jackson.core', module: 'jackson-annotations')
-        exclude(group: 'com.google.code.findbug')
-        exclude(group: 'org.slf4j')
-        exclude(group: 'org.apache.commons', module: 'commons-compress')
-    }
-
-    shaded ('com.github.docker-java:docker-java-transport-okhttp:3.2.11') {
-        exclude(group: 'com.github.docker-java', module: 'docker-java-core')
-        exclude(group: 'net.java.dev.jna')
-        exclude(group: 'org.slf4j')
-    }
-
+    api 'org.rnorth.duct-tape:duct-tape:1.0.8'
+    api 'com.github.docker-java:docker-java-api:3.2.11'
     api 'com.github.docker-java:docker-java-transport-zerodep:3.2.11'
 
+    shaded 'com.github.docker-java:docker-java-core:3.2.11'
+    shaded 'com.github.docker-java:docker-java-transport-okhttp:3.2.11', {
+        // TODO remove unused `net.java.dev.jna:jna-platform` from `docker-java-transport-okhttp`
+        exclude(group: 'net.java.dev.jna', module: 'jna-platform')
+    }
     shaded "org.yaml:snakeyaml:1.29"
-
     shaded 'org.glassfish.main.external:trilead-ssh2-repackaged:4.1.2'
+    shaded 'org.zeroturnaround:zt-exec:1.12'
 
-    shaded 'org.zeroturnaround:zt-exec:1.12', {
-        exclude(group: 'org.slf4j')
-    }
+    testCompileClasspath 'org.jetbrains:annotations:21.0.1'
 
     testImplementation 'org.apache.httpcomponents:httpclient:4.5.9'
     testImplementation 'redis.clients:jedis:3.6.0'

gradle/shading.gradle

@@ -0,0 +1,61 @@
+import java.util.jar.JarFile
+
+apply plugin: 'com.github.johnrengelman.shadow'
+
+configurations {
+    shaded
+    [apiElements, implementation, compileOnly, testCompile]*.extendsFrom shaded
+}
+configurations.api.canBeResolved = true
+
+shadowJar {
+    configurations = [project.configurations.shaded]
+    archiveClassifier.set(null)
+
+    mergeServiceFiles()
+}
+
+project.afterEvaluate {
+    def apiDependencies = project.configurations.api.resolvedConfiguration.resolvedArtifacts*.moduleVersion*.id
+    def apiFiles = project.configurations.api.resolvedConfiguration.files
+
+    // Exclude `api` dependencies, to prevent them being included into the final JAR
+    shadowJar.dependencies {
+        for (id in apiDependencies) {
+            exclude(dependency("${id.group}:${id.name}"))
+        }
+    }
+
+    // Inherit dependencies' relocators
+    shadowJar.relocators = configurations.api.dependencies.withType(ProjectDependency).collectMany {
+        return it.dependencyProject.tasks.findByName("shadowJar")?.relocators ?: []
+    }
+
+    // See https://github.com/johnrengelman/shadow/blob/5.0.0/src/main/groovy/com/github/jengelman/gradle/plugins/shadow/tasks/ConfigureShadowRelocation.groovy
+    Set<String> packages = []
+    // Always read from core's configurations
+    for (configuration in tasks.shadowJar.configurations) {
+        for (jar in configuration.resolvedConfiguration.files) {
+            if (apiFiles.contains(jar)) {
+                continue
+            }
+
+            try (def jf = new JarFile(jar)) {
+                for (entry in jf.entries()) {
+                    def name = entry.name
+                    if (name.endsWith(".class")) {
+                        def index = name.lastIndexOf('/')
+                        if (index != -1) {
+                            packages.add(name.substring(0, index))
+                        }
+                    }
+                }
+            }
+        }
+    }
+    for (pkg in packages) {
+        pkg = pkg.replaceAll('/', '.')
+
+        tasks.shadowJar.relocate(pkg, "org.testcontainers.shaded.${pkg}")
+    }
+}