Merge pull request #407 from codacy/fix-parallel

fix: Make `--parallel` run effectively in parallel CY-4739 :breaking:

Author: lolgab

README.md

@@ -334,7 +334,9 @@ sbt codacyCoverage
 
 ## Breaking Changes
 
-- 4.0.0 - Rename `analyse` command to `analyze`. This is a breaking change if you are running the CLI by using the
+- `7.0.0`: Fix `--parallel` that wasn't making the tools run actually in parallel. To restore the previous behaviour use `--parallel 1`
+
+- `4.0.0`: Rename `analyse` command to `analyze`. This is a breaking change if you are running the CLI by using the
   [jar](#java) or [`sbt`](#local), but not if you are using the [provided script](#script).
 
 ## What is Codacy

core/src/main/scala/com/codacy/analysis/core/utils/SetOps.scala

@@ -9,8 +9,11 @@ object SetOps {
 
   def mapInParallel[A, B](set: Set[A], nrParallel: Option[Int] = Option.empty[Int])(f: A => B): Seq[B] = {
     val setPar: ParSet[A] = set.par
-    setPar.tasksupport = new ForkJoinTaskSupport(new ForkJoinPool(nrParallel.getOrElse(2)))
-    setPar.map(f)(collection.breakOut)
+    val forkJoinPool = new ForkJoinPool(nrParallel.getOrElse(2))
+    setPar.tasksupport = new ForkJoinTaskSupport(forkJoinPool)
+    val result = setPar.map(f)
+    forkJoinPool.shutdown()
+    result.seq.toSeq
   }
 
 }

core/src/test/scala/com.codacy.analysis.core/utils/SetOpsSpec.scala

@@ -0,0 +1,21 @@
+package com.codacy.analysis.core.utils
+
+import org.specs2.mutable.Specification
+
+class SetOpsSpec extends Specification {
+
+  "SetOps.mapInParallel" should {
+    "actually run in parallel" in {
+      val parallelism = 10
+
+      val threadsIds = SetOps.mapInParallel(1.to(parallelism).toSet, Some(parallelism)) { _ =>
+        // If the function terminates too fast the thread pool reuses the same threads
+        Thread.sleep(100)
+
+        Thread.currentThread().getId()
+      }
+
+      threadsIds.distinct should haveSize(parallelism)
+    }
+  }
+}