reverse: fix "exclude all but" case

With test.

Fixes https://github.com/rfjakob/gocryptfs/issues/588

1 files changed, 4 insertions, 0 deletions

diff --git a/internal/fusefrontend_reverse/root_node.go b/internal/fusefrontend_reverse/root_node.go
index d57e1e6..5ce7f81 100644
--- a/internal/fusefrontend_reverse/root_node.go
+++ b/internal/fusefrontend_reverse/root_node.go
@@ -109,6 +109,10 @@ func (rn *RootNode) findLongnameParent(fd int, diriv []byte, longname string) (p
 // isExcludedPlain finds out if the plaintext path "pPath" is
 // excluded (used when -exclude is passed by the user).
 func (rn *RootNode) isExcludedPlain(pPath string) bool {
+	// root dir can't be excluded
+	if pPath == "" {
+		return false
+	}
 	return rn.excluder != nil && rn.excluder.MatchesPath(pPath)
 }