Remove excluded modules from classpath

src/main/scala/bloop/integrations/maven/MojoImplementation.scala

@@ -291,10 +291,18 @@ object MojoImplementation {
       val resolution = Some(Config.Resolution(modules))
 
       val (classpath, runtimeClasspath) = {
+        // keys of artifacts that survived Maven's exclusion resolution for this module.
+        val resolvedArtifactKeys: Set[String] = project.getArtifacts.asScala
+          .map(a => ArtifactUtils.versionlessKey(a))
+          .toSet
+
         val projectDependencies = dependencies.flatMap { d =>
-          val build = d.getBuild()
-          if (configuration == "compile") build.getOutputDirectory() :: Nil
-          else build.getTestOutputDirectory() :: build.getOutputDirectory() :: Nil
+          if (!resolvedArtifactKeys.contains(ArtifactUtils.versionlessKey(d.getArtifact))) Nil
+          else {
+            val build = d.getBuild()
+            if (configuration == "compile") build.getOutputDirectory() :: Nil
+            else build.getTestOutputDirectory() :: build.getOutputDirectory() :: Nil
+          }
         }
 
         val cp = classpath0().asScala.toList.asInstanceOf[List[String]].map(u => abs(new File(u)))

src/test/resources/exclusion/api/pom.xml

@@ -0,0 +1,17 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.example</groupId>
+    <artifactId>exclusion</artifactId>
+    <version>0.1</version>
+  </parent>
+  <artifactId>api</artifactId>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.example</groupId>
+      <artifactId>shims</artifactId>
+      <version>0.1</version>
+    </dependency>
+  </dependencies>
+</project>

src/test/resources/exclusion/consumer/pom.xml

@@ -0,0 +1,23 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.example</groupId>
+    <artifactId>exclusion</artifactId>
+    <version>0.1</version>
+  </parent>
+  <artifactId>consumer</artifactId>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.example</groupId>
+      <artifactId>api</artifactId>
+      <version>0.1</version>
+      <exclusions>
+        <exclusion>
+          <groupId>com.example</groupId>
+          <artifactId>shims</artifactId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+  </dependencies>
+</project>

src/test/resources/exclusion/pom.xml

@@ -0,0 +1,13 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.example</groupId>
+  <artifactId>exclusion</artifactId>
+  <version>0.1</version>
+  <packaging>pom</packaging>
+
+  <modules>
+    <module>shims</module>
+    <module>api</module>
+    <module>consumer</module>
+  </modules>
+</project>

src/test/resources/exclusion/shims/pom.xml

@@ -0,0 +1,9 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.example</groupId>
+    <artifactId>exclusion</artifactId>
+    <version>0.1</version>
+  </parent>
+  <artifactId>shims</artifactId>
+</project>

src/test/scala/bloop/integrations/maven/MavenConfigGenerationTest.scala

@@ -544,6 +544,39 @@ class MavenConfigGenerationTest extends BaseConfigSuite {
     }
   }
 
+  @Test
+  def exclusion() = {
+    check(
+      "exclusion/pom.xml",
+      submodules = List(
+        "exclusion/shims/pom.xml",
+        "exclusion/api/pom.xml",
+        "exclusion/consumer/pom.xml"
+      )
+    ) {
+      case (_, _, List(_, apiConfig, consumerConfig)) =>
+        // api depends on shims — shims output dir must be on api's classpath
+        assert(
+          hasCompileClasspathEntryName(apiConfig, "shims"),
+          "api should have shims on its compile classpath"
+        )
+
+        // consumer explicitly excludes shims — its output dir must NOT appear
+        assert(
+          !hasCompileClasspathEntryName(consumerConfig, "shims"),
+          "consumer should not have shims on its compile classpath"
+        )
+
+        // api itself must still be on consumer's classpath
+        assert(
+          hasCompileClasspathEntryName(consumerConfig, "api"),
+          "consumer should still have api on its compile classpath"
+        )
+      case _ =>
+        assert(false, "exclusion should have exactly three submodules")
+    }
+  }
+
   @Test
   def runtimeDependency() = {
     check("runtime_dependency/pom.xml") { (configFile, projectName, subprojects) =>