native: skip the decode hook when a reply holds no tagged value

src/arcadedb/_native/codec.py

@@ -12,6 +12,7 @@
     _np = None
 
 TAG = "\u0001"
+_TAG_ESCAPED = "\\u0001"  # TAG as it appears in reply text: NativeCodec.quote writes it as a \u escape
 _EPOCH_NAIVE = datetime(1970, 1, 1)
 
 # A list of this many Python floats or more may cross in the float32 side buffer (see _exact_float_list). A shorter one is cheaper
@@ -322,6 +323,11 @@ def _hook(obj):
 
 def loads(text: str, floats=None):
     """Decode a reply, restoring tagged values. ``floats``: the float32 tail of a binary reply (``["B", offset, count]`` values)."""
+    # A tagged value always puts the escaped tag in the text (NativeCodec.quote escapes every character below 0x20). Without it the reply
+    # holds none and the per-object hook, a Python call for every decoded object, is skipped (#151). A string or a key that merely
+    # contains U+0001 takes the hook path as before.
+    if _TAG_ESCAPED not in text:
+        return json.loads(text)
     if floats is None:
         return json.loads(text, object_hook=_hook)
 

tests/test_native_codec_loads.py

@@ -0,0 +1,73 @@
+"""codec.loads skips the per-object hook when a reply holds no tagged value (#151).
+
+The native library writes every character below 0x20 as a \\u escape (NativeCodec.quote), so a tagged value always puts the escaped tag
+in the reply text. These tests state that the fast path gives the same objects as the hook path, that it is taken only for tag-free text,
+and that a string or a key merely containing U+0001 still decodes as before.
+"""
+
+import json
+from datetime import date
+
+import pytest
+
+from arcadedb._native import codec
+
+
+def _reply(rows):
+    meta = [[f"#3:{i}", "T", "d"] for i in range(len(rows))]
+    return json.dumps(
+        {"ok": True, "rs": 1, "rows": rows, "meta": meta, "drained": True},
+        separators=(",", ":"),
+    )
+
+
+class TestLoadsWithoutTag:
+    @pytest.mark.parametrize(
+        "rows",
+        [
+            [],
+            [{"a": 1}],
+            [
+                {
+                    "name": "x",
+                    "n": 2,
+                    "f": 0.5,
+                    "flag": True,
+                    "none": None,
+                    "list": [1, 2],
+                    "map": {"k": "v"},
+                }
+            ],
+            [{"name": f"n{i}", "n": i} for i in range(1000)],
+        ],
+    )
+    def test_a_tag_free_reply_decodes_as_with_the_hook(self, rows):
+        text = _reply(rows)
+        assert codec._TAG_ESCAPED not in text
+        assert codec.loads(text) == json.loads(text, object_hook=codec._hook)
+
+    def test_the_hook_is_not_called_for_a_tag_free_reply(self, monkeypatch):
+        calls = []
+        monkeypatch.setattr(codec, "_hook", lambda obj: calls.append(obj) or obj)
+        codec.loads(_reply([{"a": 1}, {"b": 2}]))
+        assert calls == []
+
+    def test_the_float_tail_argument_does_not_change_a_tag_free_reply(self):
+        text = _reply([{"a": 1.5}])
+        assert codec.loads(text, floats=[0.25, 0.5]) == json.loads(text)
+
+
+class TestLoadsWithTag:
+    def test_a_tagged_value_is_still_restored(self):
+        text = _reply([{"d": {codec.TAG: ["D", "2026-10-31"]}}])
+        assert codec._TAG_ESCAPED in text
+        assert codec.loads(text)["rows"][0]["d"] == date(2026, 10, 31)
+
+    def test_a_string_holding_the_control_character_comes_back_unchanged(self):
+        text = _reply([{"s": "a\u0001b"}])
+        assert codec._TAG_ESCAPED in text
+        assert codec.loads(text)["rows"][0]["s"] == "a\u0001b"
+
+    def test_a_column_named_like_the_tag_is_kept(self):
+        text = _reply([{codec.TAG: "plain", "x": 1}])
+        assert codec.loads(text)["rows"][0] == {codec.TAG: "plain", "x": 1}