Add a Partest option to use a different compiler (scala#8407)

Add a Partest option to use a different compiler

Author: lrytz

project/PartestUtil.scala

@@ -37,6 +37,7 @@ object PartestUtil {
       "--instrumented", "--presentation", "--failed", "--update-check", "--no-exec",
       "--show-diff", "--show-log", "--verbose", "--terse", "--debug", "--version", "--help")
     val srcPathOption = "--srcpath"
+    val compilerPathOption = "--compilerpath"
     val grepOption = "--grep"
 
     // HACK: if we parse `--srcpath scaladoc`, we overwrite this var. The parser for test file paths
@@ -93,9 +94,14 @@ object PartestUtil {
         opt + " " + path
     }
 
+   val CompilerPath = ((token(compilerPathOption) <~ Space) ~ token(NotSpace)) map {
+     case opt ~ path =>
+       opt + " " + path
+   }
+
     val ScalacOptsParser = (token("-Dpartest.scalac_opts=") ~ token(NotSpace)) map { case opt ~ v => opt + v }
 
-    val P = oneOf(knownUnaryOptions.map(x => token(x))) | SrcPath | TestPathParser | Grep | ScalacOptsParser
+    val P = oneOf(knownUnaryOptions.map(x => token(x))) | SrcPath | CompilerPath | TestPathParser | Grep | ScalacOptsParser
     (Space ~> repsep(P, oneOrMore(Space))).map(_.mkString(" ")).?.map(_.getOrElse(""))
   }
 }

src/partest/scala/tools/partest/nest/DirectCompiler.scala

@@ -21,6 +21,7 @@ import scala.reflect.io.AbstractFile
 import scala.tools.nsc.reporters.{ConsoleReporter, Reporter}
 import scala.tools.nsc.{CompilerCommand, Global, Settings}
 import scala.util.chaining._
+import scala.sys.process._
 
 object ExtConsoleReporter {
   def apply(settings: Settings, writer: PrintWriter) = new ConsoleReporter(settings, Console.in, writer, writer).tap(_.shortname = true)
@@ -116,7 +117,7 @@ class DirectCompiler(val runner: Runner) {
       if (command.files.nonEmpty) reportError(command.files.mkString("flags file may only contain compiler options, found: ", space, ""))
     }
 
-    suiteRunner.verbose(s"% scalac ${ sources.map(_.testIdent).mkString(space) }${ if (suiteRunner.debug) " -d " + outDir else ""}")
+    suiteRunner.verbose(s"% compiling ${ sources.map(_.testIdent).mkString(space) }${ if (suiteRunner.debug) " -d " + outDir else ""}")
 
     def execCompile() =
       if (command.shouldStopWithInfo) {
@@ -134,7 +135,21 @@ class DirectCompiler(val runner: Runner) {
         result
       }
 
-    try     { execCompile() }
+    def execOtherCompiler() = {
+      val stdout = new StringBuilder
+      val stderr = new StringBuilder
+      val logger = ProcessLogger(stdout append _, stderr append _)
+      val resultCode = (suiteRunner.config.optCompilerPath.get + " " + sources.map(_.getPath).mkString(" ")) ! logger
+      logWriter append stdout
+      logWriter append stderr
+      if (resultCode == 0) runner.genPass()
+      else runner.genFail(s"compilation failed")
+    }
+
+    try {
+      if (suiteRunner.config.optCompilerPath.isEmpty) execCompile()
+      else execOtherCompiler()
+    }
     catch   { case t: Throwable => reportError(t.getMessage) ; runner.genCrash(t) }
     finally { logWriter.close() }
   }

src/partest/scala/tools/partest/nest/RunnerSpec.scala

@@ -42,6 +42,10 @@ trait RunnerSpec extends Spec with Meta.StdOpts with Interpolation {
   val optBuildPath    = "buildpath"    / "set (relative) path to build jars (ex.: --buildpath build/pack)"                --|
   val optClassPath    = "classpath"    / "set (absolute) path to build classes"                                           --|
   val optSourcePath   = "srcpath"      / "set (relative) path to test source files (ex.: --srcpath pending)"              --|
+  // Compile with a different compiler, not used internally. Used by AxLang, see PR #8407.
+  // Note: this will be much slower than creating a new global in the same JVM.
+  // Note: run tests will still use the internal Scala version for running.
+  val optCompilerPath = "compilerpath" / "set (absolute) path to a different compiler to test (ex.: --compilerpath /usr/local/bin/scalac)" --|
 
   heading("Test output options:")
   val optShowDiff     = "show-diff"    / "show diffs for failed tests"                       --?