local: fix --copy-links on macOS when cloning

Before this change, --copy-links erroneously behaved like --links when using cloning
on macOS, and cloning was not supported at all when using --links.

After this change, --copy-links does what it's supposed to, and takes advantage of
cloning when possible, by copying the file being linked to instead of the link
itself.

Cloning is now also supported in --links mode for regular files (which benefit
most from cloning). symlinks in --links mode continue to be tossed back to be
handled by rclone's special translation logic.

See https://forum.rclone.org/t/macos-local-to-local-copy-with-copy-links-causes-error/47671/5?u=nielash

backend/local/clone_darwin.go

@@ -6,6 +6,7 @@ package local
 import (
 	"context"
 	"fmt"
+	"path/filepath"
 	"runtime"
 
 	"github.com/go-darwin/apfs"
@@ -22,7 +23,7 @@ import (
 //
 // If it isn't possible then return fs.ErrorCantCopy
 func (f *Fs) Copy(ctx context.Context, src fs.Object, remote string) (fs.Object, error) {
-	if runtime.GOOS != "darwin" || f.opt.TranslateSymlinks || f.opt.NoClone {
+	if runtime.GOOS != "darwin" || f.opt.NoClone {
 		return nil, fs.ErrorCantCopy
 	}
 	srcObj, ok := src.(*Object)
@@ -30,6 +31,9 @@ func (f *Fs) Copy(ctx context.Context, src fs.Object, remote string) (fs.Object,
 		fs.Debugf(src, "Can't clone - not same remote type")
 		return nil, fs.ErrorCantCopy
 	}
+	if f.opt.TranslateSymlinks && srcObj.translatedLink { // in --links mode, use cloning only for regular files
+		return nil, fs.ErrorCantCopy
+	}
 
 	// Fetch metadata if --metadata is in use
 	meta, err := fs.GetMetadataOptions(ctx, f, src, fs.MetadataAsOpenOptions(ctx))
@@ -44,11 +48,18 @@ func (f *Fs) Copy(ctx context.Context, src fs.Object, remote string) (fs.Object,
 		return nil, err
 	}
 
-	err = Clone(srcObj.path, f.localPath(remote))
+	srcPath := srcObj.path
+	if f.opt.FollowSymlinks { // in --copy-links mode, find the real file being pointed to and pass that in instead
+		srcPath, err = filepath.EvalSymlinks(srcPath)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	err = Clone(srcPath, f.localPath(remote))
 	if err != nil {
 		return nil, err
 	}
-	fs.Debugf(remote, "server-side cloned!")
 
 	// Set metadata if --metadata is in use
 	if meta != nil {

backend/local/local_internal_test.go

@@ -73,7 +73,6 @@ func TestUpdatingCheck(t *testing.T) {
 	r.WriteFile(filePath, "content updated", time.Now())
 	_, err = in.Read(buf)
 	require.NoError(t, err)
-
 }
 
 // Test corrupted on transfer
@@ -224,7 +223,7 @@ func TestHashOnUpdate(t *testing.T) {
 	assert.Equal(t, "9a0364b9e99bb480dd25e1f0284c8555", md5)
 
 	// Reupload it with different contents but same size and timestamp
-	var b = bytes.NewBufferString("CONTENT")
+	b := bytes.NewBufferString("CONTENT")
 	src := object.NewStaticObjectInfo(filePath, when, int64(b.Len()), true, nil, f)
 	err = o.Update(ctx, b, src)
 	require.NoError(t, err)
@@ -395,7 +394,6 @@ func TestMetadata(t *testing.T) {
 			assert.Equal(t, "wedges", m["potato"])
 		}
 	})
-
 }
 
 func TestFilter(t *testing.T) {
@@ -572,4 +570,35 @@ func TestCopySymlink(t *testing.T) {
 	linkContents, err := os.Readlink(dstPath)
 	require.NoError(t, err)
 	assert.Equal(t, "file.txt", linkContents)
+
+	// Set fs into "-L/--copy-links" mode
+	f.opt.FollowSymlinks = true
+	f.opt.TranslateSymlinks = false
+	f.lstat = os.Stat
+
+	// Create dst
+	require.NoError(t, f.Mkdir(ctx, "dst2"))
+
+	// Do copy from src into dst
+	src, err = f.NewObject(ctx, "src/link.txt")
+	require.NoError(t, err)
+	require.NotNil(t, src)
+	dst, err = operations.Copy(ctx, f, nil, "dst2/link.txt", src)
+	require.NoError(t, err)
+	require.NotNil(t, dst)
+
+	// Test that we made a NON-symlink and it has the right contents
+	dstPath = filepath.Join(r.LocalName, "dst2", "link.txt")
+	fi, err := os.Lstat(dstPath)
+	require.NoError(t, err)
+	assert.True(t, fi.Mode()&os.ModeSymlink == 0)
+	want := fstest.NewItem("dst2/link.txt", "hello world", when)
+	fstest.CompareItems(t, []fs.DirEntry{dst}, []fstest.Item{want}, nil, f.precision, "")
+
+	// Test that copying a normal file also works
+	dst, err = operations.Copy(ctx, f, nil, "dst2/file.txt", dst)
+	require.NoError(t, err)
+	require.NotNil(t, dst)
+	want = fstest.NewItem("dst2/file.txt", "hello world", when)
+	fstest.CompareItems(t, []fs.DirEntry{dst}, []fstest.Item{want}, nil, f.precision, "")
 }