Fix #3738: javalib Files.createTemp*(bogusPath) no longer loops forever

javalib/src/main/scala/java/nio/file/Files.scala

@@ -277,7 +277,13 @@ object Files {
       attrs: Array[FileAttribute[_]]
   ): Path = {
     val p = if (prefix == null) "" else prefix
-    val temp = FileHelpers.createTempFile(p, "", dir, minLength = false)
+    val temp = FileHelpers.createTempFile(
+      p,
+      "",
+      dir,
+      minLength = false,
+      throwOnError = true
+    )
     if (temp.delete() && temp.mkdir()) {
       val tempPath = temp.toPath()
       setAttributes(tempPath, attrs)
@@ -307,7 +313,13 @@ object Files {
       attrs: Array[FileAttribute[_]]
   ): Path = {
     val p = if (prefix == null) "" else prefix
-    val temp = FileHelpers.createTempFile(p, suffix, dir, minLength = false)
+    val temp = FileHelpers.createTempFile(
+      p,
+      suffix,
+      dir,
+      minLength = false,
+      throwOnError = true
+    )
     val tempPath = temp.toPath()
     setAttributes(tempPath, attrs)
     tempPath

unit-tests/shared/src/test/scala/org/scalanative/testsuite/javalib/nio/file/FilesTest.scala

@@ -16,6 +16,7 @@ import StandardCopyOption._
 import org.junit.Test
 import org.junit.Assert._
 import org.junit.Assume._
+import org.junit.Ignore
 
 import scala.util.{Try, Failure}
 
@@ -552,6 +553,31 @@ class FilesTest {
     } finally Files.delete(dir)
   }
 
+  /* This test is @Ignore'd for Continuous Integration (CI) because
+   * it creates, on purpose, an infinite loop when the condition described
+   * in Issue 3738 is present: bad path argument causes an infinite loop.
+   *
+   * The test can be run manually. It passes on JVM and should soon pass
+   * on Scala Native.
+   *
+   * If ever Scala Native gets the JUnit test timeout feature, this
+   * test can be changed for use in CI.
+   */
+
+  // Issue 3738
+  @Ignore
+  @Test def filesCreateTempDirectoryDoesNotLoopInfinitely(): Unit = {
+    val path = Paths.get("/+")
+
+    try {
+      val f = Files.createTempFile(path, "Alpha", "Omega")
+      Files.delete(f)
+      fail("expected IOException or a sub-class of it")
+    } catch {
+      case e: IOException =>
+    }
+  }
+
   @Test def filesCreateTempFileWorksWithNullPrefix(): Unit = {
     val file = Files.createTempFile(null, "txt")
     try {
@@ -576,6 +602,24 @@ class FilesTest {
     } finally Files.delete(file)
   }
 
+  /* See comments above filesCreateTempDirectoryDoesNotLoopInfinitely()
+   * test above. Same song, next verse.
+   */
+
+  // Issue 3738
+  @Ignore
+  @Test def filesCreateTempFileDoesNotLoopInfinitely(): Unit = {
+    val path = Paths.get("/+")
+
+    try {
+      val f = Files.createTempFile(path, "Alpha", "Omega")
+      Files.delete(f)
+      fail("expected IOException or a sub-class of it")
+    } catch {
+      case e: IOException =>
+    }
+  }
+
   @Test def filesIsRegularFileReportsFilesAsSuch(): Unit = {
     withTemporaryDirectory { dirFile =>
       val dir = dirFile.toPath