From e31981c81293b3a2c8f1f3492ebf1ebd31155bc9 Mon Sep 17 00:00:00 2001
From: Michele Bigi <mikbigi@gmail.com>
Date: Mon, 21 Sep 2026 00:33:17 +0200
Subject: [PATCH] Persist recovered ferrite Z by comparing against the raw
 JSON.

ComponentModel validation already fills impedance from quoted ohm@freq, so snapshotting the in-memory specs skipped the write.
---
 periscope/src/backend/periscopex/graph.py |  5 +++--
 tests/test_inductor_specs.py              | 24 +++++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/periscope/src/backend/periscopex/graph.py b/periscope/src/backend/periscopex/graph.py
index 56aeb79..c8688ec 100644
--- a/periscope/src/backend/periscopex/graph.py
+++ b/periscope/src/backend/periscopex/graph.py
@@ -182,8 +182,9 @@ def _load_component_models(
             from backend.periscopex.ferrite_z import find_mpn_pdf, recover_bead_specs
 
             pdf = find_mpn_pdf(model.mpn, *pdf_dirs)
-            before_z = getattr(specs, "impedance_ohm", None)
-            before_h = getattr(specs, "value_henries", None)
+            raw_specs = raw.get("specs") if isinstance(raw.get("specs"), dict) else {}
+            before_z = raw_specs.get("impedance_ohm")
+            before_h = raw_specs.get("value_henries")
             filled = recover_bead_specs(specs, extra_text=json.dumps(raw), pdf_path=pdf)
             if filled.impedance_ohm != before_z or filled.value_henries != before_h:
                 try:
diff --git a/tests/test_inductor_specs.py b/tests/test_inductor_specs.py
index 3916265..175e683 100644
--- a/tests/test_inductor_specs.py
+++ b/tests/test_inductor_specs.py
@@ -220,6 +220,30 @@ def test_bead_mpn_datasheet_pdf_fills_z(tmp_path: Path):
     assert "100" in (persisted["specs"].get("value_formatted") or "")
 
 
+def test_bead_live_json_persist_unstuffs_henries(tmp_path: Path):
+    models = tmp_path / "models"
+    models.mkdir()
+    payload = {
+        "mpn": "BLM21PG121SN1D",
+        "specs": {
+            "specs_type": "inductor",
+            "component_subtype": "passive.ferrite_bead",
+            "value_henries": 120.0,
+            "value_formatted": "120 ohm @ 100 MHz",
+            "package": "0805",
+            "current_rating_a": "3A",
+            "dcr_ohms": 0.03,
+        },
+    }
+    (models / "BLM21PG121SN1D.json").write_text(json.dumps(payload) + "\n")
+    loaded = _load_component_models(models)
+    assert loaded["BLM21PG121SN1D"].impedance_ohm == 120.0
+    assert loaded["BLM21PG121SN1D"].value_henries is None
+    persisted = json.loads((models / "BLM21PG121SN1D.json").read_text())
+    assert persisted["specs"]["impedance_ohm"] == 120.0
+    assert persisted["specs"]["value_henries"] is None
+
+
 def test_bead_mpn_datasheet_pdf_without_z_does_not_invent(tmp_path: Path):
     models = tmp_path / "models"
     models.mkdir()