feat: gradle multi module support

Author: amgdev9

README.md

@@ -20,10 +20,10 @@ Right now, this language server is at its infancy and thus not ready to use for
 - ✅ Hover: fully working
 - 🚧 Go to definition: working except for kotlin binary dependencies (considering using the background index for this if we cannot make it work), it would also be nice to use a decompiler to jump into .class files (the analysis api provides `KotlinClassFileDecompiler` for kotlin .class files, fernflower may be used for java .class files)
 - 🚧 Build system integration: there is support for
-    * Single module Gradle projects
+    * Gradle projects (single and multi module) 
     * Single module Android projects (uses debug variant and does not handle source set merging yet)
     * Needs work on:
-        * Multi module Gradle projects
+        * Multimodule Android projects
         * KMP projects (targeting JVM, native target needs investigation on how to do it)
 
 ## Installing

app/src/main/kotlin/org/kotlinlsp/buildsystem/Gradle.kt

@@ -7,10 +7,12 @@ import org.eclipse.lsp4j.WorkDoneProgressKind
 import org.gradle.tooling.GradleConnector
 import org.gradle.tooling.events.OperationType
 import org.gradle.tooling.model.GradleModuleVersion
+import org.gradle.tooling.model.idea.IdeaModuleDependency
 import org.gradle.tooling.model.idea.IdeaProject
 import org.gradle.tooling.model.idea.IdeaSingleEntryLibraryDependency
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreApplicationEnvironment
 import org.jetbrains.kotlin.config.LanguageVersion
+import org.jetbrains.kotlin.util.collectionUtils.concat
 import org.kotlinlsp.analysis.ProgressNotifier
 import org.kotlinlsp.analysis.modules.*
 import org.kotlinlsp.common.getCachePath
@@ -97,6 +99,10 @@ class GradleBuildSystem(
                 .filter { it.scope.scope != "RUNTIME" } // We don't need runtime deps for a LSP
                 .partition { it.scope.scope == "TEST" }
 
+            val ideaSourceModuleDeps = module
+                .dependencies
+                .filterIsInstance<IdeaModuleDependency>()
+
             // Register regular dependencies
             (ideaTestDeps.asSequence() + ideaSourceDeps.asSequence()).forEach {
                 val id = it.gradleModuleVersion.formatted()
@@ -131,27 +137,42 @@ class GradleBuildSystem(
             val isAndroidModule = ideaExtraSourceDeps.isNotEmpty()  // TODO Find a better way to know this
             val sourceModuleId = module.name
             val sourceDirs = ideaSourceDirs.map { it.directory.absolutePath }
-            val sourceDeps = ideaSourceDeps.map { it.gradleModuleVersion.formatted() } + ideaExtraSourceDeps.map {
-                it.directory.toString().removePrefix("jar:")
-            } + if(!isAndroidModule) { listOf("JDK") } else { emptyList() }
+            val sourceDeps =
+                ideaSourceDeps.asSequence().map { it.gradleModuleVersion.formatted() }
+                    .plus(
+                        ideaExtraSourceDeps.map {
+                            it.directory.toString().removePrefix("jar:")
+                        }
+                    ).plus(
+                        if (!isAndroidModule) {
+                            sequenceOf("JDK")
+                        } else {
+                            emptySequence()
+                        }
+                    ).plus(
+                        ideaSourceModuleDeps.map { it.targetModuleName }
+                    )
             modules[sourceModuleId] = SerializedModule(
                 id = sourceModuleId,
                 isSource = true,
-                dependencies = sourceDeps,
+                dependencies = sourceDeps.toList(),
                 contentRoots = sourceDirs,
                 kotlinVersion = LanguageVersion.KOTLIN_2_1.versionString,   // TODO Figure out this
                 javaVersion = ideaProject.jdkName
             )
 
             // Register test module
-            if(contentRoot.testDirectories.isNotEmpty()) {
+            if (contentRoot.testDirectories.isNotEmpty()) {
                 val testModuleId = "${sourceModuleId}-test"
                 val testDirs = contentRoot.testDirectories.map { it.directory.absolutePath }
-                val testDeps = sourceDeps + ideaTestDeps.map { it.gradleModuleVersion.formatted() } + listOf(sourceModuleId)
+                val testDeps =
+                    sourceDeps
+                        .plus(ideaTestDeps.map { it.gradleModuleVersion.formatted() })
+                        .plus(sequenceOf(sourceModuleId))
                 modules[testModuleId] = SerializedModule(
                     id = testModuleId,
                     isSource = true,
-                    dependencies = testDeps,
+                    dependencies = testDeps.toList(),
                     contentRoots = testDirs,
                     kotlinVersion = LanguageVersion.KOTLIN_2_1.versionString,   // TODO Figure out this
                     javaVersion = ideaProject.jdkName

app/src/test/kotlin/org/kotlinlsp/Gradle.kt

@@ -78,6 +78,58 @@ class Gradle {
         assertEquals(modules[1].dependencies.filter { it.isSourceModule }.size, 1)
     }
 
+    @Test
+    fun `loads multi module project successfully`() = scenario("multi-module") { buildSystem ->
+        // Act
+        val (modules, _) = buildSystem.resolveModulesIfNeeded(cachedMetadata = null)!!
+
+        // Assert
+        assertEquals(modules.size, 4)
+        assertEquals(modules[0].isSourceModule, true)
+        assertEquals(
+            modules[0].contentRoots,
+            listOf(
+                Path("$cwd/test-projects/multi-module/app/src/main/java"),
+                Path("$cwd/test-projects/multi-module/app/src/main/kotlin"),
+            )
+        )
+        assertEquals(modules[0].dependencies.size, 4)
+        val depNames = modules[0].dependencies.map { it.id }.toSet()
+        assertTrue("submodule" in depNames)
+
+        assertEquals(modules[1].isSourceModule, true)
+        assertEquals(
+            modules[1].contentRoots,
+            listOf(
+                Path("$cwd/test-projects/multi-module/app/src/test/java"),
+                Path("$cwd/test-projects/multi-module/app/src/test/kotlin"),
+            )
+        )
+        assertEquals(modules[1].dependencies.size, 5)
+        assertEquals(modules[1].dependencies.filter { it.isSourceModule }.size, 2)
+
+        assertEquals(modules[2].isSourceModule, true)
+        assertEquals(
+            modules[2].contentRoots,
+            listOf(
+                Path("$cwd/test-projects/multi-module/submodule/src/main/java"),
+                Path("$cwd/test-projects/multi-module/submodule/src/main/kotlin"),
+            )
+        )
+        assertEquals(modules[2].dependencies.size, 3)
+
+        assertEquals(modules[3].isSourceModule, true)
+        assertEquals(
+            modules[3].contentRoots,
+            listOf(
+                Path("$cwd/test-projects/multi-module/submodule/src/test/java"),
+                Path("$cwd/test-projects/multi-module/submodule/src/test/kotlin"),
+            )
+        )
+        assertEquals(modules[3].dependencies.size, 4)
+        assertEquals(modules[3].dependencies.filter { it.isSourceModule }.size, 1)
+    }
+
     @Test
     fun `loads android project successfully`() = scenario("android") { buildSystem ->
         // Act