Merge pull request #29 from pielas/jar_based_scala_version_detection

Detecting scala version using manifest's Bundle-Version in case jar name doesn't contain version

Author: tgodzik

server/server/src/main/kotlin/org/jetbrains/bsp/bazel/server/sync/languages/scala/ScalaSdkResolver.kt

@@ -3,6 +3,7 @@ package org.jetbrains.bsp.bazel.server.sync.languages.scala
 import org.jetbrains.bsp.bazel.info.BspTargetInfo
 import org.jetbrains.bsp.bazel.server.paths.BazelPathsResolver
 import java.nio.file.Path
+import java.util.jar.JarFile
 import java.util.regex.Pattern
 
 class ScalaSdkResolver(private val bazelPathsResolver: BazelPathsResolver) {
@@ -27,12 +28,36 @@ class ScalaSdkResolver(private val bazelPathsResolver: BazelPathsResolver) {
     )
   }
 
-  private fun extractVersion(path: Path): String? {
+  private fun extractVersion(path: Path): String? = extractVersionFromPath(path) ?: extractVersionFromJar(path)
+
+  private fun extractVersionFromPath(path: Path): String? {
     val name = path.fileName.toString()
-    val matcher = VERSION_PATTERN.matcher(name)
+    val matcher = PATH_VERSION_PATTERN.matcher(name)
     return if (matcher.matches()) matcher.group(1) else null
   }
 
+  private fun extractVersionFromJar(path: Path): String? {
+    if (!path.toString().endsWith(".jar")) {
+      return null
+    }
+
+    try {
+      JarFile(path.toFile()).use { jar ->
+        jar.manifest?.mainAttributes?.let { attributes ->
+          attributes.getValue("Bundle-Version")?.let {
+            val versionMatcher = JAR_VERSION_PATTERN.matcher(it)
+            if (versionMatcher.find()) {
+              return versionMatcher.group(1)
+            }
+          }
+        }
+      }
+    } catch (e: Exception) {
+      e.printStackTrace()
+    }
+    return null
+  }
+
   private fun toBinaryVersion(version: String): String =
     version
       .split("\\.".toRegex())
@@ -41,7 +66,8 @@ class ScalaSdkResolver(private val bazelPathsResolver: BazelPathsResolver) {
       .joinToString(".")
 
   companion object {
-    private val VERSION_PATTERN =
+    private val PATH_VERSION_PATTERN =
       Pattern.compile("(?:processed_)?scala3?-(?:library|compiler|reflect)(?:_3)?-([.\\d]+)\\.jar")
+    private val JAR_VERSION_PATTERN = Pattern.compile("(\\d+\\.\\d+\\.\\d+)")
   }
 }