Fix step4 not able to see availavble tests

They only exist after step3 has been executed

Author: nicolasstucki

compiler/test/dotty/tools/dotc/FromTastyTests.scala

@@ -26,7 +26,7 @@ class FromTastyTests extends ParallelTesting {
     // > dotc -Ythrough-tasty -Ycheck:all <source>
 
     implicit val testGroup: TestGroup = TestGroup("posTestFromTasty")
-    val (step1, step2, step3, step4) = compileTastyInDir("tests/pos", defaultOptions,
+    val (step1, step2, step3, decompilationDir) = compileTastyInDir("tests/pos", defaultOptions,
       blacklist = Set(
         // Wrong number of arguments (only on bootstrapped)
         "i3130b.scala",
@@ -36,15 +36,19 @@ class FromTastyTests extends ParallelTesting {
 
         // MatchError in SymDenotation.sourceModule on a ThisType
         "t3612.scala",
-      ),
-      recompileBlacklist = Set(
-        "simpleCaseObject"
       )
     )
     step1.checkCompile() // Compile all files to generate the class files with tasty
     step2.checkCompile() // Compile from tasty
     step3.checkCompile() // Decompile from tasty
+
+    val step4 = compileFilesInDir(decompilationDir, defaultOptions,
+      blacklist = Set(
+        "simpleCaseObject"
+      )
+    ).keepOutput
     step4.checkCompile() // Recompile decompiled code
+
     (step1 + step2 + step3 + step4).delete()
   }
 
@@ -55,18 +59,19 @@ class FromTastyTests extends ParallelTesting {
     // > dotr Test
 
     implicit val testGroup: TestGroup = TestGroup("runTestFromTasty")
-    val (step1, step2, step3, step4) = compileTastyInDir("tests/run", defaultOptions,
+    val (step1, step2, step3, decompilationDir) = compileTastyInDir("tests/run", defaultOptions,
       blacklist = Set(
         // Closure type miss match
         "eff-dependent.scala",
-      ),
-      recompileBlacklist = Set(
       )
     )
     step1.checkCompile() // Compile all files to generate the class files with tasty
     step2.checkRuns() // Compile from tasty and run the result
     step3.checkCompile() // Decompile from tasty
-    step4.checkRuns() // Recompile decompiled code
+
+    val step4 = compileFilesInDir(decompilationDir, defaultOptions, blacklist = Set()).keepOutput
+    step4.checkRuns() // Recompile and run decompiled code
+
     (step1 + step2 + step3 + step4).delete()
   }
 

compiler/test/dotty/tools/vulpix/ParallelTesting.scala

@@ -1258,8 +1258,8 @@ trait ParallelTesting extends RunnerOrchestration { self =>
    *  Tests in the first part of the tuple must be executed before the second.
    *  Both testsRequires explicit delete().
    */
-  def compileTastyInDir(f: String, flags0: TestFlags, blacklist: Set[String], recompileBlacklist: Set[String])(
-      implicit testGroup: TestGroup): (CompilationTest, CompilationTest, CompilationTest, CompilationTest) = {
+  def compileTastyInDir(f: String, flags0: TestFlags, blacklist: Set[String])(
+      implicit testGroup: TestGroup): (CompilationTest, CompilationTest, CompilationTest, String) = {
     val outDir = defaultOutputDir + testGroup + "/"
     val flags = flags0 and "-Yretain-trees"
     val sourceDir = new JFile(f)
@@ -1286,14 +1286,12 @@ trait ParallelTesting extends RunnerOrchestration { self =>
     val generateClassFiles = compileFilesInDir(f, flags0, blacklist)
 
     val decompilationDir = outDir + sourceDir.getName + "_decompiled"
-    new JFile(decompilationDir).mkdirs()
-    val recompileDecompiled = compileFilesInDir(decompilationDir, flags0, recompileBlacklist)
 
     (
       generateClassFiles.keepOutput,
       new CompilationTest(targets).keepOutput,
       new CompilationTest(targets2).keepOutput,
-      recompileDecompiled.keepOutput
+      decompilationDir
     )
   }