cmount: Add optional brew tag to throw an error when using mount in the

binaries installed via Homebrew - Fixes #4775

Signed-off-by: Anagh Kumar Baranwal <6824881+darthShadow@users.noreply.github.com>

cmd/cmount/mount_brew.go

@@ -0,0 +1,32 @@
+// Build for macos with the brew tag to handle the absence
+// of fuse and print an appropriate error message
+
+// +build brew
+// +build darwin
+
+package cmount
+
+import (
+	"github.com/pkg/errors"
+	"github.com/rclone/rclone/cmd/mountlib"
+	"github.com/rclone/rclone/vfs"
+)
+
+func init() {
+	name := "mount"
+	cmd := mountlib.NewMountCommand(name, false, mount)
+	cmd.Aliases = append(cmd.Aliases, "cmount")
+	mountlib.AddRc("cmount", mount)
+}
+
+// mount the file system
+//
+// The mount point will be ready when this returns.
+//
+// returns an error, and an error channel for the serve process to
+// report an error when fusermount is called.
+func mount(_ *vfs.VFS, _ string, _ *mountlib.Options) (<-chan error, func() error, error) {
+	return nil, nil, errors.New("mount is not supported on MacOS when installed via Homebrew. " +
+		"Please install the binaries available at https://rclone." +
+		"org/downloads/ instead if you want to use the mount command")
+}

cmd/cmount/mount_unsupported.go

@@ -1,6 +1,6 @@
 // Build for cmount for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-// +build !linux,!darwin,!freebsd,!windows !cgo !cmount
+// +build !linux,!darwin,!freebsd,!windows !brew !cgo !cmount
 
 package cmount

cmd/mount/mount_unsupported.go

@@ -1,7 +1,7 @@
 // Build for mount for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-// Invert the build constraint: linux,go1.13 darwin,go1.13 freebsd,go1.13
+// Invert the build constraint: linux,go1.13 freebsd,go1.13
 //
 // !((linux&&go1.13) || (freebsd&&go1.13))
 // == !(linux&&go1.13) && !(freebsd&&go1.13))