commands: add --force option to files cp command (#10823)

* commands: add `--force` option to `files cp` command

Adds a `--force` option to allow the `ipfs files cp` command to overwrite existig files. Returns error is trying to overwrite directories.

Replaces #4079

Closes #2074

* Update test/sharness/t0250-files-api.sh

core/commands/files.go

@@ -440,10 +440,10 @@ being GC'ed.
 		cmds.StringArg("dest", true, false, "Destination within MFS."),
 	},
 	Options: []cmds.Option{
+		cmds.BoolOption(forceOptionName, "Force overwrite of existing files."),
 		cmds.BoolOption(filesParentsOptionName, "p", "Make parent directories as needed."),
 	},
 	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
-		mkParents, _ := req.Options[filesParentsOptionName].(bool)
 		nd, err := cmdenv.GetNode(env)
 		if err != nil {
 			return err
@@ -459,8 +459,6 @@ being GC'ed.
 			return err
 		}
 
-		flush, _ := req.Options[filesFlushOptionName].(bool)
-
 		src, err := checkPath(req.Arguments[0])
 		if err != nil {
 			return err
@@ -500,6 +498,7 @@ being GC'ed.
 			return errFilesCpInvalidUnixFS
 		}
 
+		mkParents, _ := req.Options[filesParentsOptionName].(bool)
 		if mkParents {
 			err := ensureContainingDirectoryExists(nd.FilesRoot, dst, prefix)
 			if err != nil {
@@ -507,11 +506,19 @@ being GC'ed.
 			}
 		}
 
+		force, _ := req.Options[forceOptionName].(bool)
+		if force {
+			if err = unlinkNodeIfExists(nd, dst); err != nil {
+				return fmt.Errorf("cp: cannot unlink existing file: %s", err)
+			}
+		}
+
 		err = mfs.PutNode(nd.FilesRoot, dst, node)
 		if err != nil {
 			return fmt.Errorf("cp: cannot put node in path %s: %s", dst, err)
 		}
 
+		flush, _ := req.Options[filesFlushOptionName].(bool)
 		if flush {
 			if _, err := mfs.FlushPath(req.Context, nd.FilesRoot, dst); err != nil {
 				return fmt.Errorf("cp: cannot flush the created file %s: %s", dst, err)
@@ -546,6 +553,35 @@ func getNodeFromPath(ctx context.Context, node *core.IpfsNode, api iface.CoreAPI
 	}
 }
 
+func unlinkNodeIfExists(node *core.IpfsNode, path string) error {
+	dir, name := gopath.Split(path)
+	parent, err := mfs.Lookup(node.FilesRoot, dir)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil
+		}
+		return err
+	}
+
+	pdir, ok := parent.(*mfs.Directory)
+	if !ok {
+		return fmt.Errorf("not a directory: %s", dir)
+	}
+
+	// Attempt to unlink if child is a file, ignore error since
+	// we are only concerned with unlinking an existing file.
+	child, err := pdir.Child(name)
+	if err != nil {
+		return nil // no child file, nothing to unlink
+	}
+
+	if child.Type() != mfs.TFile {
+		return fmt.Errorf("not a file: %s", path)
+	}
+
+	return pdir.Unlink(name)
+}
+
 type filesLsOutput struct {
 	Entries []mfs.NodeListing
 }

docs/changelogs/v0.36.md

@@ -10,7 +10,8 @@ This release  was brought to you by the [Shipyard](http://ipshipyard.com/) team.
 
 - [Overview](#overview)
 - [🔦 Highlights](#-highlights)
-  - [Update go-log to v2](#update-go-log-to-v2
+  - [Update go-log to v2](#update-go-log-to-v2)
+  - [Overwrite option for files cp command](#overwrite-option-for-files-cp-command)
   - [Option for filestore command to remove bad blocks](#option-for-filestore-command-to-remove-bad-blocks)
   - [📦️ Important dependency updates](#-important-dependency-updates)
 - [📝 Changelog](#-changelog)
@@ -29,6 +30,10 @@ go-log v2 has been out for quite a while now and it is time to deprecate v1.
 - Fixes `ipfs log tail`
 - Removes support for `ContextWithLoggable` as this is not needed for tracing-like functionality
 
+#### Overwrite option for files cp command
+
+The `ipfs files cp` command has a `--force` option to allow it to overwrite existing files. Attempting to overwrite an existing directory results in an error.
+
 #### Option for filestore command to remove bad blocks
 
 The `filestore` command has a new option, `--remove-bad-blocks`, to verify objects in the filestore and remove those that fail verification.

test/sharness/t0250-files-api.sh

@@ -674,6 +674,18 @@ test_files_api() {
     ipfs files ls /adir | grep foobar
   '
 
+  test_expect_success "test copy --force overwrites files" '
+    ipfs files cp /ipfs/$FILE1 /file1 &&
+    ipfs files cp /ipfs/$FILE2 /file2 &&
+    ipfs files cp --force /file1 /file2 &&
+    test "`ipfs files read /file1`" = "`ipfs files read /file2`"
+  '
+
+  test_expect_success "clean up" '
+    ipfs files rm /file1 &&
+    ipfs files rm /file2
+  '
+
   test_expect_success "should fail to write file and create intermediate directories with no --parents flag set $EXTRA" '
     echo "ipfs rocks" | test_must_fail ipfs files write --create /parents/foo/ipfs.txt
   '