Make signature artifact timestamps deterministic

tests/test_generate_popular_node_signatures.py

@@ -2,7 +2,9 @@ import json
 import tempfile
 import textwrap
 import unittest
+from datetime import datetime, timezone
 from pathlib import Path
+from unittest import mock
 
 from tools.generate_popular_node_signatures import (
     extract_repo_signatures,
@@ -12,10 +14,6 @@ from tools.generate_popular_node_signatures import (
 
 
 class StaticExtractionTests(unittest.TestCase):
-    def _normalise_generated_at(self, text):
-        parsed = json.loads(text)
-        return text.replace(parsed["generated_at"], "<generated-at>")
-
     def _extract_source(self, source, pack_id="sample-pack"):
         with tempfile.TemporaryDirectory() as tmp:
             Path(tmp, "__init__.py").write_text(textwrap.dedent(source), encoding="utf-8")
@@ -4766,9 +4764,23 @@ NODE_CLASS_MAPPINGS = {
         self.assertEqual("no_static_nodes", result["pack"]["status"])
 
     def test_write_artifact_is_deterministic(self):
+        class FakeDateTime:
+            values = iter(
+                (
+                    datetime(2026, 1, 1, tzinfo=timezone.utc),
+                    datetime(2026, 1, 2, tzinfo=timezone.utc),
+                )
+            )
+
+            @classmethod
+            def now(cls, tz=None):
+                value = next(cls.values)
+                return value if tz is None else value.astimezone(tz)
+
         with tempfile.TemporaryDirectory() as tmp:
             out_one = Path(tmp, "one.json")
             out_two = Path(tmp, "two.json")
+            with mock.patch("tools.generate_popular_node_signatures.datetime", FakeDateTime):
                 write_artifact(
                     out_one,
                     sources={
@@ -4867,7 +4879,21 @@ NODE_CLASS_MAPPINGS = {
 
         self.assertEqual(["a-pack", "b-pack"], list(parsed["packs"]))
         self.assertEqual(["ANode", "BNode"], list(parsed["nodes"]))
-        self.assertEqual(self._normalise_generated_at(text_one), self._normalise_generated_at(text_two))
+        self.assertEqual(text_one, text_two)
+
+    def test_write_artifact_uses_explicit_generated_at(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            out = Path(tmp, "popular_node_signatures.json")
+            write_artifact(
+                out,
+                sources={"manager_url": "https://example.invalid/manager.json", "limit": 1},
+                packs={},
+                nodes={},
+                generated_at="2026-07-02T00:00:00Z",
+            )
+            parsed = json.loads(out.read_text(encoding="utf-8"))
+
+        self.assertEqual("2026-07-02T00:00:00Z", parsed["generated_at"])
 
 
 if __name__ == "__main__":

tools/generate_popular_node_signatures.py

@@ -10,6 +10,7 @@ from pathlib import Path
 SCHEMA_VERSION = 1
 MANAGER_LIST_URL = "https://raw.githubusercontent.com/ltdrdata/ComfyUI-Manager/main/custom-node-list.json"
 REGISTRY_NODES_URL = "https://api.comfy.org/nodes"
+DEFAULT_GENERATED_AT = "1970-01-01T00:00:00Z"
 
 
 class UnsupportedStaticExpression(Exception):
@@ -2410,10 +2411,20 @@ def _sorted_json_value(value):
     return value
 
 
-def write_artifact(path, sources, packs, nodes):
+def _format_generated_at(generated_at):
+    if isinstance(generated_at, datetime):
+        if generated_at.tzinfo is None:
+            generated_at = generated_at.replace(tzinfo=timezone.utc)
+        else:
+            generated_at = generated_at.astimezone(timezone.utc)
+        return generated_at.replace(microsecond=0).isoformat().replace("+00:00", "Z")
+    return str(generated_at)
+
+
+def write_artifact(path, sources, packs, nodes, *, generated_at=DEFAULT_GENERATED_AT):
     payload = {
         "schema_version": SCHEMA_VERSION,
-        "generated_at": datetime.now(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z"),
+        "generated_at": _format_generated_at(generated_at),
         "sources": _sorted_json_value(sources),
         "packs": _sorted_json_value(packs),
         "nodes": _sorted_json_value(nodes),