Improve move docs and add tests

Author: fzhinkin

core/common/src/files/FileSystem.kt

@@ -62,7 +62,7 @@ public sealed interface FileSystem {
      * Atomically renames [source] to [destination] overriding [destination] if it already exists.
      *
      * When the filesystem does not support atomic move of [source] and [destination] corresponds to different
-     * filesystems and the operation could not be performed atomically,
+     * filesystems (or different volumes, on Windows) and the operation could not be performed atomically,
      * [UnsupportedOperationException] is thrown.
      *
      * @param source the path to rename.

core/common/test/files/SmokeFileTest.kt

@@ -107,6 +107,33 @@ class SmokeFileTest {
         }
     }
 
+    @OptIn(ExperimentalStdlibApi::class)
+    @Test
+    fun atomicMoveDir() {
+        val src = createTempPath()
+        val dst = createTempPath()
+        FileSystem.System.createDirectories(src)
+
+        FileSystem.System.atomicMove(src, dst)
+        assertFalse(FileSystem.System.exists(src))
+        assertTrue(FileSystem.System.exists(dst))
+
+        val src2 = createTempPath()
+        FileSystem.System.createDirectories(src2)
+        FileSystem.System.atomicMove(src2, dst)
+        assertFalse(FileSystem.System.exists(src2))
+
+        val src3 = createTempPath()
+        FileSystem.System.sink(src3).buffered().use { it.writeString("hehe") }
+        assertFailsWith<IOException> { FileSystem.System.atomicMove(src3, dst) }
+
+        val dstFile = createTempPath()
+        FileSystem.System.sink(dstFile).buffered().use { it.writeString("hehe") }
+        val srcDir = createTempPath()
+        FileSystem.System.createDirectories(srcDir)
+        assertFailsWith<IOException> { FileSystem.System.atomicMove(srcDir, dstFile) }
+    }
+
     @Test
     fun deleteFile() {
         val p = createTempPath()

core/jvm/src/files/FileSystemJvm.kt

@@ -23,10 +23,15 @@ private class NioMover : Mover {
         if (!source.file.exists()) {
             throw FileNotFoundException("Source file does not exist: ${source.file}")
         }
-        Files.move(
-            source.file.toPath(), destination.file.toPath(),
-            StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING
-        )
+        try {
+            Files.move(
+                source.file.toPath(), destination.file.toPath(),
+                StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING
+            )
+        } catch (e: Throwable) {
+            if (e is IOException) throw e
+            throw IOException("Move failed", e)
+        }
     }
 }