union: fix rename not working with union of local disk and bucket based remote

Before this change the union's feature flags were a strict AND of the
underlying remotes. This means that a union of a local disk (which can
Move but not Copy) and a bucket based remote (which can Copy but not
Move) could neither Move nor Copy.

This fix advertises Move in the union if all the remotes can Move or
Copy. It also implements Move as Copy+Delete (like rclone does
normally) if the underlying union does not support Move.

This enables renames to work with unions of local disk and bucket
based remotes expected.

Fixes #5632

backend/union/union_internal_test.go

@@ -3,10 +3,15 @@ package union
 import (
 	"bytes"
 	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
 	"testing"
 	"time"
 
+	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/object"
+	"github.com/rclone/rclone/fs/operations"
 	"github.com/rclone/rclone/fstest"
 	"github.com/rclone/rclone/fstest/fstests"
 	"github.com/rclone/rclone/lib/random"
@@ -14,6 +19,22 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// MakeTestDirs makes directories in /tmp for testing
+func MakeTestDirs(t *testing.T, n int) (dirs []string, clean func()) {
+	for i := 1; i <= n; i++ {
+		dir, err := ioutil.TempDir("", fmt.Sprintf("rclone-union-test-%d", n))
+		require.NoError(t, err)
+		dirs = append(dirs, dir)
+	}
+	clean = func() {
+		for _, dir := range dirs {
+			err := os.RemoveAll(dir)
+			assert.NoError(t, err)
+		}
+	}
+	return dirs, clean
+}
+
 func (f *Fs) TestInternalReadOnly(t *testing.T) {
 	if f.name != "TestUnionRO" {
 		t.Skip("Only on RO union")
@@ -65,3 +86,83 @@ func (f *Fs) InternalTest(t *testing.T) {
 }
 
 var _ fstests.InternalTester = (*Fs)(nil)
+
+// This specifically tests a union of local which can Move but not
+// Copy and :memory: which can Copy but not Move to makes sure that
+// the resulting union can Move
+func TestMoveCopy(t *testing.T) {
+	if *fstest.RemoteName != "" {
+		t.Skip("Skipping as -remote set")
+	}
+	ctx := context.Background()
+	dirs, clean := MakeTestDirs(t, 1)
+	defer clean()
+	fsString := fmt.Sprintf(":union,upstreams='%s :memory:bucket':", dirs[0])
+	f, err := fs.NewFs(ctx, fsString)
+	require.NoError(t, err)
+
+	unionFs := f.(*Fs)
+	fLocal := unionFs.upstreams[0].Fs
+	fMemory := unionFs.upstreams[1].Fs
+
+	t.Run("Features", func(t *testing.T) {
+		assert.NotNil(t, f.Features().Move)
+		assert.Nil(t, f.Features().Copy)
+
+		// Check underlying are as we are expect
+		assert.NotNil(t, fLocal.Features().Move)
+		assert.Nil(t, fLocal.Features().Copy)
+		assert.Nil(t, fMemory.Features().Move)
+		assert.NotNil(t, fMemory.Features().Copy)
+	})
+
+	// Put a file onto the local fs
+	contentsLocal := random.String(50)
+	fileLocal := fstest.NewItem("local.txt", contentsLocal, time.Now())
+	_, _ = fstests.PutTestContents(ctx, t, fLocal, &fileLocal, contentsLocal, true)
+	objLocal, err := f.NewObject(ctx, fileLocal.Path)
+	require.NoError(t, err)
+
+	// Put a file onto the memory fs
+	contentsMemory := random.String(60)
+	fileMemory := fstest.NewItem("memory.txt", contentsMemory, time.Now())
+	_, _ = fstests.PutTestContents(ctx, t, fMemory, &fileMemory, contentsMemory, true)
+	objMemory, err := f.NewObject(ctx, fileMemory.Path)
+	require.NoError(t, err)
+
+	fstest.CheckListing(t, f, []fstest.Item{fileLocal, fileMemory})
+
+	t.Run("MoveLocal", func(t *testing.T) {
+		fileLocal.Path = "local-renamed.txt"
+		_, err := operations.Move(ctx, f, nil, fileLocal.Path, objLocal)
+		require.NoError(t, err)
+		fstest.CheckListing(t, f, []fstest.Item{fileLocal, fileMemory})
+
+		// Check can retrieve object from union
+		obj, err := f.NewObject(ctx, fileLocal.Path)
+		require.NoError(t, err)
+		assert.Equal(t, fileLocal.Size, obj.Size())
+
+		// Check can retrieve object from underlying
+		obj, err = fLocal.NewObject(ctx, fileLocal.Path)
+		require.NoError(t, err)
+		assert.Equal(t, fileLocal.Size, obj.Size())
+
+		t.Run("MoveMemory", func(t *testing.T) {
+			fileMemory.Path = "memory-renamed.txt"
+			_, err := operations.Move(ctx, f, nil, fileMemory.Path, objMemory)
+			require.NoError(t, err)
+			fstest.CheckListing(t, f, []fstest.Item{fileLocal, fileMemory})
+
+			// Check can retrieve object from union
+			obj, err := f.NewObject(ctx, fileMemory.Path)
+			require.NoError(t, err)
+			assert.Equal(t, fileMemory.Size, obj.Size())
+
+			// Check can retrieve object from underlying
+			obj, err = fMemory.NewObject(ctx, fileMemory.Path)
+			require.NoError(t, err)
+			assert.Equal(t, fileMemory.Size, obj.Size())
+		})
+	})
+}