Deprecate createTempFile/createTempDir functions

Document their potential permission problems.
Suppress this deprecation in tests.

libraries/stdlib/jvm/src/kotlin/io/files/Utils.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -23,11 +23,24 @@ import java.io.IOException
  *
  * To create the new file, the [prefix] and the [suffix] may first be adjusted to fit the limitations of the underlying platform.
  *
+ * **Note:** if the new directory is created in a directory that is shared with all users,
+ * it may get permissions allowing everyone to read it or its content, thus creating a risk of leaking
+ * sensitive information stored in this directory.
+ * To avoid this, it's recommended either to specify an explicit parent [directory] that is not shared widely,
+ * or to use alternative ways of creating temporary files,
+ * such as [java.nio.file.Files.createTempDirectory](https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#createTempDirectory-java.lang.String-java.nio.file.attribute.FileAttribute...-)
+ * or the experimental `createTempDirectory` function in the `kotlin.io.path` package.
+ *
  * @return a file object corresponding to a newly-created directory.
  *
  * @throws IOException in case of input/output error.
  * @throws IllegalArgumentException if [prefix] is shorter than three symbols.
  */
+@Deprecated(
+    "Avoid creating temporary directories in the default temp location with this function " +
+    "due to too wide permissions on the newly created directory. " +
+    "Use kotlin.io.path.createTempDirectory instead."
+)
 public fun createTempDir(prefix: String = "tmp", suffix: String? = null, directory: File? = null): File {
     val dir = File.createTempFile(prefix, suffix, directory)
     dir.delete()
@@ -50,11 +63,24 @@ public fun createTempDir(prefix: String = "tmp", suffix: String? = null, directo
  *
  * To create the new file, the [prefix] and the [suffix] may first be adjusted to fit the limitations of the underlying platform.
  *
+ * **Note:** if the new file is created in a directory that is shared with all users,
+ * it may get permissions allowing everyone to read it, thus creating a risk of leaking
+ * sensitive information stored in this file.
+ * To avoid this, it's recommended either to specify an explicit parent [directory] that is not shared widely,
+ * or to use alternative ways of creating temporary files,
+ * such as [java.nio.file.Files.createTempFile](https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#createTempFile-java.lang.String-java.lang.String-java.nio.file.attribute.FileAttribute...-)
+ * or the experimental `createTempFile` function in the `kotlin.io.path` package.
+ *
  * @return a file object corresponding to a newly-created file.
  *
  * @throws IOException in case of input/output error.
  * @throws IllegalArgumentException if [prefix] is shorter than three symbols.
  */
+@Deprecated(
+    "Avoid creating temporary files in the default temp location with this function " +
+    "due to too wide permissions on the newly created file. " +
+    "Use kotlin.io.path.createTempFile instead or resort to java.io.File.createTempFile."
+)
 public fun createTempFile(prefix: String = "tmp", suffix: String? = null, directory: File? = null): File {
     return File.createTempFile(prefix, suffix, directory)
 }

libraries/stdlib/jvm/test/io/FileTreeWalks.kt

@@ -16,7 +16,7 @@ class FileTreeWalkTest {
         val referenceFilenames =
                 listOf("1", "1/2", "1/3", "1/3/4.txt", "1/3/5.txt", "6", "7.txt", "8", "8/9.txt")
         fun createTestFiles(): File {
-            val basedir = createTempDir()
+            val basedir = @Suppress("DEPRECATION") createTempDir()
             for (name in referenceFilenames) {
                 val file = basedir.resolve(name)
                 if (file.extension.isEmpty())
@@ -52,7 +52,7 @@ class FileTreeWalkTest {
     }
 
     @Test fun singleFile() {
-        val testFile = createTempFile()
+        val testFile = @Suppress("DEPRECATION") createTempFile()
         val nonExistantFile = testFile.resolve("foo")
         try {
             for (walk in listOf(File::walkTopDown, File::walkBottomUp)) {
@@ -437,6 +437,7 @@ class FileTreeWalkTest {
         }
     }
 
+    @Suppress("DEPRECATION")
     @Test fun streamFileTree() {
         val dir = createTempDir()
         try {

libraries/stdlib/jvm/test/io/Files.kt

@@ -17,12 +17,14 @@ class FilesTest {
     private val isBackslashSeparator = File.separatorChar == '\\'
 
 
+    @Suppress("DEPRECATION")
     @Test fun testPath() {
         val fileSuf = System.currentTimeMillis().toString()
         val file1 = createTempFile("temp", fileSuf)
         assertTrue(file1.path.endsWith(fileSuf), file1.path)
     }
 
+    @Suppress("DEPRECATION")
     @Test fun testCreateTempDir() {
         val dirSuf = System.currentTimeMillis().toString()
         val dir1 = createTempDir("temp", dirSuf)
@@ -42,6 +44,7 @@ class FilesTest {
         dir3.delete()
     }
 
+    @Suppress("DEPRECATION")
     @Test fun testCreateTempFile() {
         val fileSuf = System.currentTimeMillis().toString()
         val file1 = createTempFile("temp", fileSuf)
@@ -61,6 +64,7 @@ class FilesTest {
         file3.delete()
     }
 
+    @Suppress("DEPRECATION")
     @Test fun listFilesWithFilter() {
         val dir = createTempDir("temp")
 
@@ -366,7 +370,7 @@ class FilesTest {
     }
 
     @Test fun writeReadText() {
-        val file = createTempFile()
+        val file = @Suppress("DEPRECATION") createTempFile()
         try {
             val expected = String(CharArray(DEFAULT_BUFFER_SIZE * 2) { Random.nextInt(0, 1024).toChar() })
             file.writeText(expected)
@@ -391,7 +395,7 @@ class FilesTest {
     }
 
     @Test fun writeReadBytes() {
-        val file = createTempFile()
+        val file = @Suppress("DEPRECATION") createTempFile()
         try {
             val expected = Random.nextBytes(DEFAULT_BUFFER_SIZE * 4)
             file.writeBytes(expected)
@@ -427,8 +431,8 @@ class FilesTest {
     }
 
     @Test fun testCopyTo() {
-        val srcFile = createTempFile()
+        val srcFile = @Suppress("DEPRECATION") createTempFile()
-        val dstFile = createTempFile()
+        val dstFile = @Suppress("DEPRECATION") createTempFile()
         try {
             srcFile.writeText("Hello, World!")
             assertFailsWith(FileAlreadyExistsException::class, "copy do not overwrite existing file") {
@@ -493,8 +497,8 @@ class FilesTest {
 
     @Test fun copyToNameWithoutParent() {
         val currentDir = File("").absoluteFile!!
-        val srcFile = createTempFile()
+        val srcFile = @Suppress("DEPRECATION") createTempFile()
-        val dstFile = createTempFile(directory = currentDir)
+        val dstFile = @Suppress("DEPRECATION") createTempFile(directory = currentDir)
         try {
             srcFile.writeText("Hello, World!", Charsets.UTF_8)
             dstFile.delete()
@@ -512,7 +516,7 @@ class FilesTest {
     }
 
     @Test fun deleteRecursively() {
-        val dir = createTempDir()
+        val dir = @Suppress("DEPRECATION") createTempDir()
         dir.delete()
         dir.mkdir()
         val subDir = File(dir, "subdir");
@@ -563,6 +567,7 @@ class FilesTest {
         }
     }
 
+    @Suppress("DEPRECATION")
     @Test fun copyRecursively() {
         val src = createTempDir()
         val dst = createTempDir()
@@ -629,6 +634,7 @@ class FilesTest {
         }
     }
 
+    @Suppress("DEPRECATION")
     @Test fun copyRecursivelyWithOverwrite() {
         val src = createTempDir()
         val dst = createTempDir()
@@ -675,7 +681,7 @@ class FilesTest {
     }
 
     @Test fun helpers2() {
-        val file = createTempFile()
+        val file = @Suppress("DEPRECATION") createTempFile()
         val writer = file.printWriter()
         val str1 = "Hello, world!"
         val str2 = "Everything is wonderful!"

libraries/stdlib/jvm/test/io/IOStreams.kt

@@ -12,7 +12,7 @@ import kotlin.random.Random
 
 class IOStreamsTest {
     @Test fun testGetStreamOfFile() {
-        val tmpFile = createTempFile()
+        val tmpFile = @Suppress("DEPRECATION") createTempFile()
         var writer: Writer? = null
         try {
             writer = tmpFile.outputStream().writer()
@@ -46,7 +46,7 @@ class IOStreamsTest {
     }
 
     @Test fun readWriteBytes() {
-        val file = createTempFile("temp", Random.nextLong().toString())
+        val file = @Suppress("DEPRECATION") createTempFile("temp", Random.nextLong().toString())
         try {
             val bytes = Random.nextBytes(256_000)