[pp:metadata] fix handling of empty directory paths (#7296)

gallery_dl/path.py

@@ -269,7 +269,7 @@ class PathFormat():
         try:
             for fmt in self.directory_formatters:
                 segment = fmt(kwdict).strip()
-                if strip and segment != "..":
+                if strip and segment not in {".", ".."}:
                     # remove trailing dots and spaces (#647)
                     segment = segment.rstrip(strip)
                 if segment:

gallery_dl/postprocessor/metadata.py

@@ -180,7 +180,10 @@ class MetadataPP(PostProcessor):
             pathfmt.directory_formatters = self._directory_formatters
             pathfmt.directory_conditions = ()
             segments = pathfmt.build_directory(pathfmt.kwdict)
-            directory = pathfmt.clean_path(os.sep.join(segments) + os.sep)
+            if segments:
+                directory = pathfmt.clean_path(os.sep.join(segments) + os.sep)
+            else:
+                directory = "." + os.sep
             return os.path.join(self._base(pathfmt), directory)
         finally:
             pathfmt.directory_conditions = conditions

test/test_postprocessor.py

@@ -511,6 +511,17 @@ class MetadataTest(BasePostprocessorTest):
         path = self.pathfmt.realdirectory + "../json/12500/file.ext.json"
         m.assert_called_once_with(path, "w", encoding="utf-8")
 
+    def test_metadata_directory_empty(self):
+        self._create(
+            {"directory": []},
+        )
+
+        with patch("builtins.open", mock_open()) as m:
+            self._trigger()
+
+        path = self.pathfmt.realdirectory + "./file.ext.json"
+        m.assert_called_once_with(path, "w", encoding="utf-8")
+
     def test_metadata_basedirectory(self):
         self._create({"base-directory": True})