Improve automatic module handling in module graph construction

Add all automatic modules to roots if at least one automatic module is
added, as per
http://cr.openjdk.java.net/~mr/jigsaw/spec/api/java/lang/module/package-summary.html

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/ClasspathRootsResolver.kt

@@ -172,11 +172,21 @@ internal class ClasspathRootsResolver(
             else -> computeDefaultRootModules() + additionalModules
         }
 
-        // TODO: if at least one automatic module is added, add all automatic modules as per java.lang.module javadoc
-        val allDependencies = javaModuleGraph.getAllDependencies(rootModules).also { loadedModules ->
-            report(LOGGING, "Loading modules: $loadedModules")
+        val allDependencies = javaModuleGraph.getAllDependencies(rootModules).toMutableList()
+
+        if (allDependencies.any { moduleName -> javaModuleFinder.findModule(moduleName) is JavaModule.Automatic }) {
+            // According to java.lang.module javadoc, if at least one automatic module is added to the module graph,
+            // all observable automatic modules should be added.
+            // There are no automatic modules in the JDK, so we select all automatic modules out of user modules
+            for (module in modules) {
+                if (module is JavaModule.Automatic) {
+                    allDependencies += module.name
+                }
+            }
         }
 
+        report(LOGGING, "Loading modules: $allDependencies")
+
         for (moduleName in allDependencies) {
             val module = javaModuleFinder.findModule(moduleName)
             if (module == null) {

compiler/testData/javaModules/namedAgainstSeveralAutomatic/autoA/foo/Foo.java

@@ -0,0 +1,3 @@
+package foo;
+
+public class Foo {}

compiler/testData/javaModules/namedAgainstSeveralAutomatic/autoB/bar/Bar.java

@@ -0,0 +1,3 @@
+package bar;
+
+public class Bar {}

compiler/testData/javaModules/namedAgainstSeveralAutomatic/main.txt

@@ -0,0 +1 @@
+OK

compiler/testData/javaModules/namedAgainstSeveralAutomatic/main/module-info.java

@@ -0,0 +1,3 @@
+module main {
+    requires autoB;
+}

compiler/testData/javaModules/namedAgainstSeveralAutomatic/main/usage.kt

@@ -0,0 +1,6 @@
+import foo.Foo
+import bar.Bar
+
+fun usage(): String {
+    return "${Foo()}${Bar()}"
+}

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/autoA/foo/Foo.java

@@ -0,0 +1,3 @@
+package foo;
+
+public class Foo {}

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/autoB/bar/Bar.java

@@ -0,0 +1,3 @@
+package bar;
+
+public class Bar {}

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/main.txt

@@ -0,0 +1 @@
+OK

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/main/usage.kt

@@ -0,0 +1,6 @@
+import foo.Foo
+import bar.Bar
+
+fun usage(): String {
+    return "${Foo()}${Bar()}"
+}

compiler/tests/org/jetbrains/kotlin/jvm/compiler/Java9ModulesIntegrationTest.kt

@@ -198,4 +198,19 @@ class Java9ModulesIntegrationTest : AbstractKotlinCompilerIntegrationTest() {
 
         module("main", listOf(m1, m2))
     }
+
+    fun testUnnamedAgainstSeveralAutomatic() {
+        val a = module("autoA")
+        val b = module("autoB")
+        // Even though we only add autoA to the module graph, autoB should be added as well because autoA, being automatic,
+        // transitively requires every other automatic module, and in particular, autoB.
+        // Furthermore, because autoB is automatic, main should read autoB
+        module("main", listOf(a, b), addModules = listOf("autoA"))
+    }
+
+    fun testNamedAgainstSeveralAutomatic() {
+        val a = module("autoA")
+        val b = module("autoB")
+        module("main", listOf(a, b))
+    }
 }