diff --git a/stepmania/src/RageUtil_FileDB.cpp b/stepmania/src/RageUtil_FileDB.cpp
index 6b0757df73..667f4ccd6d 100644
--- a/stepmania/src/RageUtil_FileDB.cpp
+++ b/stepmania/src/RageUtil_FileDB.cpp
@@ -130,6 +130,7 @@ int FilenameDB::GetFileHash( const CString &sPath )
 	return fs->GetFileHash(Name);
 }
 
+/* path should be fully collapsed, so we can operate in-place: no . or .. */
 bool FilenameDB::ResolvePath(CString &path)
 {
 	if( path == "." || path == "" )
@@ -153,6 +154,8 @@ bool FilenameDB::ResolvePath(CString &path)
 			fs = GetFileSet( ret );
 
 		CString p = path.substr( begin, size );
+		RAGE_ASSERT_M( p.size() != 1 || p[0] != '.', path ); // no .
+		RAGE_ASSERT_M( p.size() != 2 || p[0] != '.' || p[1] != '.', path ); // no ..
 		set<File>::iterator it = fs->files.find( File(p) );
 
 		/* If there were no matches, the path isn't found. */