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author | Stefan Zeiger <szeiger@novocode.com> | 2016-08-12 18:24:46 +0200 |
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committer | GitHub <noreply@github.com> | 2016-08-12 18:24:46 +0200 |
commit | 18bdbc83e1ac9baafbf18940ad1b87e4122fc978 (patch) | |
tree | 095995a837f3ac92fd94d780aa0e9bb5171de7a5 | |
parent | 0d9587a563ff26852732e9bb751f601972fecddc (diff) | |
parent | 53d55bc821a11a886094008211d43f2ee9b4c638 (diff) | |
download | scala-18bdbc83e1ac9baafbf18940ad1b87e4122fc978.tar.gz scala-18bdbc83e1ac9baafbf18940ad1b87e4122fc978.tar.bz2 scala-18bdbc83e1ac9baafbf18940ad1b87e4122fc978.zip |
Merge pull request #5312 from szeiger/issue/8434-2
SI-8434 Make generic Set operations build the same kind of Set
-rw-r--r-- | src/library/scala/collection/generic/GenSetFactory.scala | 6 | ||||
-rw-r--r-- | test/junit/scala/collection/NewBuilderTest.scala | 184 |
2 files changed, 189 insertions, 1 deletions
diff --git a/src/library/scala/collection/generic/GenSetFactory.scala b/src/library/scala/collection/generic/GenSetFactory.scala index 800f66eb53..65404a4991 100644 --- a/src/library/scala/collection/generic/GenSetFactory.scala +++ b/src/library/scala/collection/generic/GenSetFactory.scala @@ -40,7 +40,11 @@ abstract class GenSetFactory[CC[X] <: GenSet[X] with GenSetLike[X, CC[X]]] /** $setCanBuildFromInfo */ def setCanBuildFrom[A] = new CanBuildFrom[CC[_], A, CC[A]] { - def apply(from: CC[_]) = newBuilder[A] + def apply(from: CC[_]) = from match { + // When building from an existing Set, try to preserve its type: + case from: Set[_] => from.genericBuilder.asInstanceOf[Builder[A, CC[A]]] + case _ => newBuilder[A] + } def apply() = newBuilder[A] } } diff --git a/test/junit/scala/collection/NewBuilderTest.scala b/test/junit/scala/collection/NewBuilderTest.scala new file mode 100644 index 0000000000..fdc6af113d --- /dev/null +++ b/test/junit/scala/collection/NewBuilderTest.scala @@ -0,0 +1,184 @@ +package scala.collection + +import scala.{collection => sc} +import scala.collection.{mutable => scm, immutable => sci, parallel => scp, concurrent => scc} +import scala.collection.parallel.{mutable => scpm, immutable => scpi} + +import org.junit.runner.RunWith +import org.junit.runners.JUnit4 +import org.junit.Test +import scala.reflect.ClassTag +import org.junit.Assert._ + +/* Tests various maps by making sure they all agree on the same answers. */ +@RunWith(classOf[JUnit4]) +class NewBuilderTest { + + @Test + def mapPreservesCollectionType() { + def test[T: ClassTag](mapped: Any): Unit = { + val expected = reflect.classTag[T].runtimeClass + val isInstance = reflect.classTag[T].runtimeClass.isInstance(mapped) + assertTrue(s"$mapped (of class ${mapped.getClass} is not a in instance of ${expected}", isInstance) + } + + test[sc.GenTraversable[_] ]((sc.GenTraversable(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.Traversable[_] ]((sc.Traversable(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.GenIterable[_] ]((sc.GenIterable(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.Iterable[_] ]((sc.Iterable(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.GenSeq[_] ]((sc.GenSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.Seq[_] ]((sc.Seq(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.LinearSeq[_] ]((sc.LinearSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.LinearSeq[_] ]((sc.LinearSeq(1): sc.Seq[Int] ).map(x => x)) + test[sc.IndexedSeq[_] ]((sc.IndexedSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.IndexedSeq[_] ]((sc.IndexedSeq(1): sc.Seq[Int] ).map(x => x)) + test[sc.GenSet[_] ]((sc.GenSet(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.Set[_] ]((sc.Set(1): sc.GenTraversable[Int]).map(x => x)) + test[sc.GenMap[_, _] ]((sc.GenMap(1 -> 1): sc.GenMap[Int, Int] ).map(x => x)) + test[sc.Map[_, _] ]((sc.Map(1 -> 1): sc.GenMap[Int, Int] ).map(x => x)) + + test[scm.Traversable[_] ]((scm.Traversable(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.Iterable[_] ]((scm.Iterable(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.LinearSeq[_] ]((scm.LinearSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.LinearSeq[_] ]((scm.LinearSeq(1): sc.Seq[Int] ).map(x => x)) + test[scm.MutableList[_] ]((scm.MutableList(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.MutableList[_] ]((scm.MutableList(1): sc.Seq[Int] ).map(x => x)) + test[scm.Queue[_] ]((scm.Queue(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.Queue[_] ]((scm.Queue(1): sc.Seq[Int] ).map(x => x)) + test[scm.DoubleLinkedList[_]]((scm.DoubleLinkedList(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.DoubleLinkedList[_]]((scm.DoubleLinkedList(1): sc.Seq[Int] ).map(x => x)) + test[scm.LinkedList[_] ]((scm.LinkedList(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.LinkedList[_] ]((scm.LinkedList(1): sc.Seq[Int] ).map(x => x)) + test[scm.ArrayStack[_] ]((scm.ArrayStack(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.ArrayStack[_] ]((scm.ArrayStack(1): sc.Seq[Int] ).map(x => x)) + test[scm.Stack[_] ]((scm.Stack(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.Stack[_] ]((scm.Stack(1): sc.Seq[Int] ).map(x => x)) + test[scm.ArraySeq[_] ]((scm.ArraySeq(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.ArraySeq[_] ]((scm.ArraySeq(1): sc.Seq[Int] ).map(x => x)) + + test[scm.Buffer[_] ]((scm.Buffer(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.Buffer[_] ]((scm.Buffer(1): sc.Seq[Int] ).map(x => x)) + test[scm.IndexedSeq[_] ]((scm.IndexedSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.IndexedSeq[_] ]((scm.IndexedSeq(1): sc.Seq[Int] ).map(x => x)) + test[scm.ArrayBuffer[_] ]((scm.ArrayBuffer(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.ArrayBuffer[_] ]((scm.ArrayBuffer(1): sc.Seq[Int] ).map(x => x)) + test[scm.ListBuffer[_] ]((scm.ListBuffer(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.ListBuffer[_] ]((scm.ListBuffer(1): sc.Seq[Int] ).map(x => x)) + test[scm.Seq[_] ]((scm.Seq(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.Seq[_] ]((scm.Seq(1): sc.Seq[Int] ).map(x => x)) + test[scm.ResizableArray[_] ]((scm.ResizableArray(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.ResizableArray[_] ]((scm.ResizableArray(1): sc.Seq[Int] ).map(x => x)) + test[scm.Set[_] ]((scm.Set(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.Set[_] ]((scm.Set(1): sc.Set[Int] ).map(x => x)) + test[scm.HashSet[_] ]((scm.HashSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.HashSet[_] ]((scm.HashSet(1): sc.Set[Int] ).map(x => x)) + test[scm.LinkedHashSet[_] ]((scm.LinkedHashSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scm.LinkedHashSet[_] ]((scm.LinkedHashSet(1): sc.Set[Int] ).map(x => x)) + + test[sci.Traversable[_] ]((sci.Traversable(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Iterable[_] ]((sci.Iterable(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.LinearSeq[_] ]((sci.LinearSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.LinearSeq[_] ]((sci.LinearSeq(1): sc.Seq[Int] ).map(x => x)) + test[sci.List[_] ]((sci.List(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.List[_] ]((sci.List(1): sc.Seq[Int] ).map(x => x)) + test[sci.Stream[_] ]((sci.Stream(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Stream[_] ]((sci.Stream(1): sc.Seq[Int] ).map(x => x)) + test[sci.Stack[_] ]((sci.Stack(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Stack[_] ]((sci.Stack(1): sc.Seq[Int] ).map(x => x)) + test[sci.Queue[_] ]((sci.Queue(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Queue[_] ]((sci.Queue(1): sc.Seq[Int] ).map(x => x)) + test[sci.IndexedSeq[_] ]((sci.IndexedSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.IndexedSeq[_] ]((sci.IndexedSeq(1): sc.Seq[Int] ).map(x => x)) + test[sci.Vector[_] ]((sci.Vector(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Vector[_] ]((sci.Vector(1): sc.Seq[Int] ).map(x => x)) + test[sci.Seq[_] ]((sci.Seq(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Seq[_] ]((sci.Seq(1): sc.Seq[Int] ).map(x => x)) + test[sci.Set[_] ]((sci.Set(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.Set[_] ]((sci.Set(1): sc.Set[Int] ).map(x => x)) + test[sci.ListSet[_] ]((sci.ListSet(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.ListSet[_] ]((sci.ListSet(1): sc.Set[Int] ).map(x => x)) + test[sci.HashSet[_] ]((sci.HashSet(1): sc.GenTraversable[Int]).map(x => x)) + test[sci.HashSet[_] ]((sci.HashSet(1): sc.Set[Int] ).map(x => x)) + + test[scp.ParIterable[_] ]((scp.ParIterable(1): sc.GenTraversable[Int]).map(x => x)) + test[scp.ParSeq[_] ]((scp.ParSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[scp.ParSeq[_] ]((scp.ParSeq(1): sc.GenSeq[Int] ).map(x => x)) + test[scp.ParSet[_] ]((scp.ParSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scp.ParSet[_] ]((scp.ParSet(1): sc.GenSet[Int] ).map(x => x)) + + test[scpm.ParIterable[_] ]((scpm.ParIterable(1): sc.GenTraversable[Int]).map(x => x)) + test[scpm.ParSeq[_] ]((scpm.ParSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[scpm.ParSeq[_] ]((scpm.ParSeq(1): sc.GenSeq[Int] ).map(x => x)) + test[scpm.ParArray[_] ]((scpm.ParArray(1): sc.GenTraversable[Int]).map(x => x)) + test[scpm.ParArray[_] ]((scpm.ParArray(1): sc.GenSeq[Int] ).map(x => x)) + test[scpm.ParSet[_] ]((scpm.ParSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scpm.ParSet[_] ]((scpm.ParSet(1): sc.GenSet[Int] ).map(x => x)) + test[scpm.ParHashSet[_] ]((scpm.ParHashSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scpm.ParHashSet[_] ]((scpm.ParHashSet(1): sc.GenSet[Int] ).map(x => x)) + + test[scpi.ParIterable[_] ]((scpi.ParIterable(1): sc.GenTraversable[Int]).map(x => x)) + test[scpi.ParSeq[_] ]((scpi.ParSeq(1): sc.GenTraversable[Int]).map(x => x)) + test[scpi.ParSeq[_] ]((scpi.ParSeq(1): sc.GenSeq[Int] ).map(x => x)) + test[scpi.ParVector[_] ]((scpi.ParVector(1): sc.GenTraversable[Int]).map(x => x)) + test[scpi.ParVector[_] ]((scpi.ParVector(1): sc.GenSeq[Int] ).map(x => x)) + test[scpi.ParSet[_] ]((scpi.ParSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scpi.ParSet[_] ]((scpi.ParSet(1): sc.GenSet[Int] ).map(x => x)) + test[scpi.ParHashSet[_] ]((scpi.ParHashSet(1): sc.GenTraversable[Int]).map(x => x)) + test[scpi.ParHashSet[_] ]((scpi.ParHashSet(1): sc.GenSet[Int] ).map(x => x)) + + // These go through `GenMap.canBuildFrom`. There is no simple fix for Map like there is for Set. + // A Map does not provide access to its companion object at runtime. (The `companion` field + // points to an inherited `GenericCompanion`, not the actual companion object). Therefore, the + // `MapCanBuildFrom` has no way to get the correct builder for the source type at runtime. + //test[scm.Map[_, _] ]((scm.Map(1 -> 1): sc.GenMap[Int, Int]).map(x => x) + //test[scm.OpenHashMap[_, _] ]((scm.OpenHashMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scm.LongMap[_] ]((scm.LongMap(1L -> 1): sc.GenMap[Long, Int]).map(x => x)) + //test[scm.ListMap[_, _] ]((scm.ListMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scm.LinkedHashMap[_, _]]((scm.LinkedHashMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scm.HashMap[_, _] ]((scm.HashMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sci.Map[_, _] ]((sci.Map(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sci.ListMap[_, _] ]((sci.ListMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sci.IntMap[_] ]((sci.IntMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sci.LongMap[_] ]((sci.LongMap(1L -> 1): sc.GenMap[Long, Int]).map(x => x)) + //test[sci.HashMap[_, _] ]((sci.HashMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sci.SortedMap[_, _] ]((sci.SortedMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sci.TreeMap[_, _] ]((sci.TreeMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scc.TrieMap[_, _] ]((scc.TrieMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scp.ParMap[_, _] ]((scp.ParMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scpm.ParMap[_, _] ]((scpm.ParMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scpm.ParHashMap[_, _] ]((scpm.ParHashMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scpm.ParTrieMap[_, _] ]((scpm.ParTrieMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scpi.ParMap[_, _] ]((scpi.ParMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scpi.ParHashMap[_, _] ]((scpi.ParHashMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + + // These cannot be expected to work. The static type information is lost, and `map` does not capture + // a `ClassTag` of the result type, so there is no way for a `CanBuildFrom` to decide to build another + // `BitSet` instead of a generic `Set` implementation: + //test[scm.BitSet ]((scm.BitSet(1): sc.GenTraversable[Int]).map(x => x)) + //test[scm.BitSet ]((scm.BitSet(1): sc.Set[Int]).map(x => x)) + + // These also require a `ClassTag`: + //test[scm.UnrolledBuffer[_]]((scm.UnrolledBuffer(1): sc.GenTraversable[Int]).map(x => x)) + //test[scm.UnrolledBuffer[_]]((scm.UnrolledBuffer(1): sc.Seq[Int]).map(x => x)) + + // The situation is similar for sorted collection. They require an implicit `Ordering` which cannot + // be captured at runtime by a `CanBuildFrom` when the static type has been lost: + //test[sc.SortedMap[_, _] ]((sc.SortedMap(1 -> 1): sc.GenTraversable[(Int, Int)]).map(x => x)) + //test[sc.SortedMap[_, _] ]((sc.SortedMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[sc.SortedSet[_] ]((sc.SortedSet(1): sc.GenTraversable[Int]).map(x => x)) + //test[sc.SortedSet[_] ]((sc.SortedSet(1): sc.Set[Int]).map(x => x)) + //test[scm.SortedSet[_] ]((scm.SortedSet(1): sc.GenTraversable[Int]).map(x => x)) + //test[scm.SortedSet[_] ]((scm.SortedSet(1): sc.Set[Int]).map(x => x)) + //test[scm.TreeSet[_] ]((scm.TreeSet(1): sc.GenTraversable[Int]).map(x => x)) + //test[scm.TreeSet[_] ]((scm.TreeSet(1): sc.Set[Int]).map(x => x)) + //test[scm.TreeMap[_, _] ]((scm.TreeMap(1 -> 1): sc.GenTraversable[(Int, Int)]).map(x => x)) + //test[scm.TreeMap[_, _] ]((scm.TreeMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + //test[scm.SortedMap[_, _] ]((scm.SortedMap(1 -> 1): sc.GenTraversable[(Int, Int)]).map(x => x)) + //test[scm.SortedMap[_, _] ]((scm.SortedMap(1 -> 1): sc.GenMap[Int, Int]).map(x => x)) + + // Maps do not map to maps when seen as GenTraversable. This would require knowledge that `map` + // returns a `Tuple2`, which is not available dynamically: + //test[sc.GenMap[_, _] ]((sc.GenMap(1 -> 1): sc.GenTraversable[(Int, Int)]).map(x => x)) + //test[sc.Map[_, _] ]((sc.Map(1 -> 1): sc.GenTraversable[(Int, Int)]).map(x => x)) + } +} |