language-support/scala: add support for specifying dependency roots explicitly

docs/source/support/release-notes.rst

@@ -20,6 +20,12 @@ Sandbox
 - Introduced a new API for party management.
   See `#1312 <https://github.com/digital-asset/daml/issues/1312>`__.
 
+Scala bindings
+~~~~~~~~~~~~~~
+
+- New `--root` command-line option for limiting what templates are selected for codegen.
+  See `#1210 <https://github.com/digital-asset/daml/pull/1210>`__.
+
 .. _release-0-12-24:
 
 0.12.24 - 2019-06-06

language-support/codegen-common/src/main/scala/com/digitalasset/daml/lf/codegen/conf/Conf.scala

@@ -22,7 +22,8 @@ final case class Conf(
     darFiles: Map[Path, Option[String]] = Map(),
     outputDirectory: Path,
     decoderPkgAndClass: Option[(String, String)] = None,
-    verbosity: Level = Level.ERROR
+    verbosity: Level = Level.ERROR,
+    roots: List[String] = Nil
 )
 
 object Conf {
@@ -57,6 +58,12 @@ object Conf {
       .action((l, c) => c.copy(verbosity = l))
       .text("Verbosity between 0 (only show errors) and 4 (show all messages) -- defaults to 0")
 
+    opt[String]('r', "root")(Read.stringRead)
+      .unbounded()
+      .action((rexp, c) => c.copy(roots = rexp :: c.roots))
+      .text(
+        "Regular expression for fully-qualified names of templates to generate -- defaults to .*")
+
     help("help").text("This help text")
 
   }

language-support/scala/codegen/BUILD.bazel

@@ -89,5 +89,6 @@ da_scala_test_suite(
         "//daml-lf/archive:daml_lf_archive_scala",
         "//daml-lf/data",
         "//daml-lf/interface",
+        "//daml-lf/transaction-scalacheck",
     ],
 )

language-support/scala/codegen/src/main/scala/com/digitalasset/codegen/CodeGen.scala

@@ -10,7 +10,6 @@ import iface.{Type => _, _}
 import com.digitalasset.daml.lf.iface.reader.{Errors, InterfaceReader}
 import java.io._
 
-import scala.collection.breakOut
 import com.digitalasset.codegen.dependencygraph._
 import com.digitalasset.codegen.exception.PackageInterfaceException
 import com.digitalasset.daml.lf.data.ImmArray.ImmArraySeq
@@ -29,7 +28,9 @@ import scalaz.syntax.std.option._
 import scalaz.syntax.bind._
 import scalaz.syntax.traverse1._
 
+import scala.collection.breakOut
 import scala.util.{Failure, Success}
+import scala.util.matching.Regex
 
 object CodeGen {
 
@@ -59,12 +60,17 @@ object CodeGen {
   @throws[PackageInterfaceException](
     cause = "either decoding a package from a file or extracting" +
       " the package interface failed")
-  def generateCode(files: List[File], packageName: String, outputDir: File, mode: Mode): Unit =
+  def generateCode(
+      files: List[File],
+      packageName: String,
+      outputDir: File,
+      mode: Mode,
+      roots: Seq[String] = Seq()): Unit =
     files match {
       case Nil =>
         throw PackageInterfaceException("Expected at least one DAR or DALF input file.")
       case f :: fs =>
-        generateCodeSafe(NonEmptyList(f, fs: _*), packageName, outputDir, mode)
+        generateCodeSafe(NonEmptyList(f, fs: _*), packageName, outputDir, mode, roots)
           .fold(es => throw PackageInterfaceException(formatErrors(es)), identity)
     }
 
@@ -75,9 +81,11 @@ object CodeGen {
       files: NonEmptyList[File],
       packageName: String,
       outputDir: File,
-      mode: Mode): ValidationNel[String, Unit] =
+      mode: Mode,
+      roots: Seq[String]): ValidationNel[String, Unit] =
     decodeInterfaces(files).map { ifaces: NonEmptyList[EnvironmentInterface] =>
-      val combinedIface: EnvironmentInterface = combineEnvInterfaces(ifaces)
+      val combinedIface: EnvironmentInterface =
+        combineEnvInterfaces(ifaces map filterTemplatesBy(roots map (_.r)))
       packageInterfaceToScalaCode(util(mode, packageName, combinedIface, outputDir))
     }
 
@@ -135,6 +143,26 @@ object CodeGen {
   private def combineEnvInterfaces(as: NonEmptyList[EnvironmentInterface]): EnvironmentInterface =
     as.suml1
 
+  // Template names can be filtered by given regexes (default: use all templates)
+  // If a template does not match any regex, it becomes a "normal" datatype.
+  private[codegen] def filterTemplatesBy(regexes: Seq[Regex])(
+      ei: EnvironmentInterface): EnvironmentInterface = {
+
+    def matchesRoots(qualName: Ref.Identifier): Boolean =
+      regexes.exists(_.findFirstIn(qualName.qualifiedName.qualifiedName).isDefined)
+    // scala-2.13-M4: _.matches(qualName.qualifiedName.qualifiedName)
+
+    if (regexes.isEmpty) ei
+    else {
+      val EnvironmentInterface(tds) = ei
+      EnvironmentInterface(tds transform {
+        case (id, tpl @ InterfaceType.Template(_, _)) if !matchesRoots(id) =>
+          InterfaceType.Normal(tpl.`type`)
+        case (_, other) => other
+      })
+    }
+  }
+
   private def packageInterfaceToScalaCode(util: Util): Unit = {
     val interface = util.iface
 

language-support/scala/codegen/src/main/scala/com/digitalasset/codegen/Main.scala

@@ -20,11 +20,11 @@ object Main extends StrictLogging {
 
   def main(args: Array[String]): Unit =
     Conf.parse(args) match {
-      case Some(Conf(darMap, outputDir, decoderPkgAndClass, verbosity)) =>
+      case Some(Conf(darMap, outputDir, decoderPkgAndClass, verbosity, roots)) =>
         setGlobalLogLevel(verbosity)
         logUnsupportedEventDecoderOverride(decoderPkgAndClass)
         val (dars, packageName) = darsAndOnePackageName(darMap)
-        CodeGen.generateCode(dars, packageName, outputDir.toFile, CodeGen.Novel)
+        CodeGen.generateCode(dars, packageName, outputDir.toFile, CodeGen.Novel, roots)
       case None =>
         throw new IllegalArgumentException(
           s"Invalid ${codegenId: String} command line arguments: ${args.mkString(" "): String}")

language-support/scala/codegen/src/test/scala/com/digitalasset/codegen/CodeGenSpec.scala

@@ -0,0 +1,53 @@
+// Copyright (c) 2019 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package com.digitalasset
+package codegen
+
+import daml.lf.data.ImmArray.ImmArraySeq
+import daml.lf.data.Ref.Identifier
+import daml.lf.iface._
+import daml.lf.value.ValueGenerators.idGen
+
+import org.scalatest.{WordSpec, Matchers}
+import org.scalatest.prop.GeneratorDrivenPropertyChecks
+
+class CodeGenSpec extends WordSpec with Matchers with GeneratorDrivenPropertyChecks {
+  import CodeGen.filterTemplatesBy
+  import CodeGenSpec._
+
+  "filterTemplatesBy" should {
+    "be identity given empty regexes" in forAll(trivialEnvInterfaceGen) { ei =>
+      filterTemplatesBy(Seq.empty)(ei) should ===(ei)
+    }
+
+    "delete all templates given impossible regex" in forAll(trivialEnvInterfaceGen) { ei =>
+      val noTemplates = ei copy (ei.typeDecls transform {
+        case (_, tmpl @ InterfaceType.Template(_, _)) => InterfaceType.Normal(tmpl.`type`)
+        case (_, v) => v
+      })
+      filterTemplatesBy(Seq("(?!a)a".r))(ei) should ===(noTemplates)
+    }
+
+    "match the union of regexes, not intersection" in forAll(trivialEnvInterfaceGen) { ei =>
+      filterTemplatesBy(Seq("(?s).*".r, "(?!a)a".r))(ei) should ===(ei)
+    }
+  }
+}
+
+object CodeGenSpec {
+  import org.scalacheck.{Arbitrary, Gen}
+  import Arbitrary.arbitrary
+
+  val trivialEnvInterfaceGen: Gen[EnvironmentInterface] = {
+    val fooRec = Record(ImmArraySeq.empty)
+    val fooTmpl = InterfaceType.Template(fooRec, DefTemplate(Map.empty))
+    val fooNorm = InterfaceType.Normal(DefDataType(ImmArraySeq.empty, fooRec))
+    implicit val idArb: Arbitrary[Identifier] = Arbitrary(idGen)
+    arbitrary[Map[Identifier, Boolean]] map { ids =>
+      EnvironmentInterface(ids transform { (_, isTemplate) =>
+        if (isTemplate) fooTmpl else fooNorm
+      })
+    }
+  }
+}