[fix] Correctly determine language type for JVM binary targets (#306)

CHANGELOG.md

@@ -28,12 +28,14 @@
 - `JVMLanguagePluginParser.calculateJVMSourceRoot` does not throw 
   an exception for package longer than the path.
   | [#294](https://github.com/JetBrains/bazel-bsp/pull/294)
-- Fix transitive target failure check in bloop export.
+- Fix transitive target failure check in bloop export.aa
   | [#287](https://github.com/JetBrains/bazel-bsp/pull/287)
 - Use direct source dependencies for thrift targets if present.
   | [#298](https://github.com/JetBrains/bazel-bsp/pull/298)
 - Postpone bazel info.
   | [#300](https://github.com/JetBrains/bazel-bsp/pull/300)
+- Correctly determine language type for JVM binary targets.
+  | [#306](https://github.com/JetBrains/bazel-bsp/pull/306)
 
 ## [2.2.1] - 09.08.2022
 

server/src/main/java/org/jetbrains/bsp/bazel/server/sync/BazelProjectMapper.kt

@@ -89,15 +89,22 @@ class BazelProjectMapper(
         target.dependenciesList.map { Label(it.id) }
 
     private fun inferLanguages(target: TargetInfo): Set<Language> =
-        target.sourcesList.flatMap { source: FileLocation ->
-            Language.all().filter { isLanguageFile(source, it) }
-        }.toHashSet()
+        if (target.sourcesList.isEmpty()) {
+            Language.all().filter { isBinaryTargetOfLanguage(target.kind, it) }.toHashSet()
+        } else {
+            target.sourcesList.flatMap { source: FileLocation ->
+                Language.all().filter { isLanguageFile(source, it) }
+            }.toHashSet()
+        }
 
     private fun isLanguageFile(file: FileLocation, language: Language): Boolean =
         language.extensions.any {
             file.relativePath.endsWith(it)
         }
 
+    private fun isBinaryTargetOfLanguage(kind: String, language: Language): Boolean =
+        language.binary_targets.contains(kind)
+
     private fun resolveSourceSet(target: TargetInfo, languagePlugin: LanguagePlugin<*>): SourceSet {
         val sources = target.sourcesList.asSequence().map(bazelPathsResolver::resolve)
         val sourceRoots = sources.mapNotNull(languagePlugin::calculateSourceRoot)

server/src/main/java/org/jetbrains/bsp/bazel/server/sync/model/Language.kt

@@ -3,11 +3,12 @@ package org.jetbrains.bsp.bazel.server.sync.model
 enum class Language(
     val id: String,
     val extensions: Set<String>,
-    dependentNames: Set<String> = hashSetOf()
+    val binary_targets: Set<String> = hashSetOf(),
+    dependentNames: Set<String> = hashSetOf(),
 ) {
     SCALA("scala", hashSetOf(".scala")),
-    JAVA("java", hashSetOf(".java")),
-    KOTLIN("kotlin", hashSetOf(".kt"), hashSetOf(JAVA.id)),
+    JAVA("java", hashSetOf(".java"), binary_targets = setOf("java_binary")),
+    KOTLIN("kotlin", hashSetOf(".kt"), setOf("kt_jvm_binary"), hashSetOf(JAVA.id)),
     CPP("cpp", hashSetOf(".C", ".cc", ".cpp", ".CPP", ".c++", ".cp", "cxx", ".h", ".hpp")),
     THRIFT("thrift", hashSetOf(".thrift"));