Join KiCad hierarchical PNM/MPN when the BOM CSV omits a designator.

Child-sheet symbol fields fill graph mpn; empty sheet fields stay empty. A sibling .kicad_sch next to a PADS netlist is used the same way.

tests/test_kicad_parser.py

@@ -417,3 +417,112 @@ def test_cyclic_sheet_include_is_rejected(tmp_path: Path):
     ))
     with pytest.raises(ValueError, match="[Cc]yclic"):
         parse_kicad(root)
+
+
+def _ic_symbol(ref: str, value: str, *, pnm: str = "", mpn: str = "", x: float = 0, y: float = 0) -> str:
+    uid = "aaaaaaaa-aaaa-aaaa-aaaa-" + ref.encode().hex()[:12].ljust(12, "0")
+    extra = ""
+    if pnm:
+        extra += (
+            f'    (property "PNM" "{pnm}" (at 0 0 0) '
+            f'(effects (font (size 1.27 1.27))))\n'
+        )
+    if mpn:
+        extra += (
+            f'    (property "MPN" "{mpn}" (at 0 0 0) '
+            f'(effects (font (size 1.27 1.27))))\n'
+        )
+    return f"""
+  (symbol
+    (lib_id "Device:R")
+    (at {x} {y} 0)
+    (unit 1)
+    (uuid "{uid}")
+    (property "Reference" "{ref}" (at 0 0 0) (effects (font (size 1.27 1.27))))
+    (property "Value" "{value}" (at 0 0 0) (effects (font (size 1.27 1.27))))
+{extra}    (pin "1" (uuid "p1{ref}"))
+    (pin "2" (uuid "p2{ref}"))
+  )
+"""
+
+
+def _hier_root_with_child(tmp_path: Path, child_body: str) -> Path:
+    child = tmp_path / "codec.kicad_sch"
+    child.write_text(_sch(
+        child_body,
+        """
+  (global_label "GND" (at 0 3.81 0) (uuid "cccccccccccccccccccccccccccccccccccc"))
+""",
+    ))
+    root = tmp_path / "root.kicad_sch"
+    root.write_text(_sch(
+        _resistor("R1", "10k"),
+        """
+  (global_label "GND" (at 0 3.81 0) (uuid "bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb"))
+  (sheet
+    (at 50 0)
+    (size 20 20)
+    (property "Sheetname" "Codec" (at 50 0 0) (effects (font (size 1.27 1.27))))
+    (property "Sheetfile" "codec.kicad_sch" (at 50 0 0) (effects (font (size 1.27 1.27))))
+  )
+""",
+    ))
+    return root
+
+
+def test_hierarchical_pnm_fills_graph_when_bom_omits_ref(tmp_path: Path):
+    from backend.periscopex.graph import build_graph
+
+    root = _hier_root_with_child(
+        tmp_path,
+        _ic_symbol("U13", "TPD2E007DCKR", pnm="TPD2E007DCKR"),
+    )
+    bom = tmp_path / "bom.csv"
+    bom.write_text(
+        "Reference,Value,Footprint,PNM\n"
+        "R1,10k,0603,\n"
+        '"U9,U14,U26",TPD2E007DCKR,SOT23,TPD2E007DCKR\n'
+    )
+    g = build_graph(
+        root, bom, tmp_path / "ex", tmp_path / "pat", tmp_path / "mod",
+        mpn_col="Manufacturer Part Number",
+    )
+    assert "U13" not in (bom.read_text())
+    assert g.components["U13"].mpn == "TPD2E007DCKR"
+    assert g.schematic_fields["U13"]["cad_sheet"] == "codec.kicad_sch"
+
+
+def test_hierarchical_empty_fields_do_not_invent_mpn(tmp_path: Path):
+    from backend.periscopex.graph import build_graph
+
+    root = _hier_root_with_child(tmp_path, _ic_symbol("U15", "", pnm="", mpn=""))
+    bom = tmp_path / "bom.csv"
+    bom.write_text("Reference,Value,PNM\nR1,10k,\n")
+    g = build_graph(
+        root, bom, tmp_path / "ex", tmp_path / "pat", tmp_path / "mod",
+        mpn_col="Manufacturer Part Number",
+    )
+    assert g.components["U15"].mpn in (None, "")
+    assert not (g.components["U15"].mpn or "").strip()
+
+
+def test_pads_netlist_joins_sibling_hierarchical_sch(tmp_path: Path):
+    from backend.periscopex.graph import build_graph
+
+    _hier_root_with_child(
+        tmp_path,
+        _ic_symbol("U13", "TPD2E007DCKR", pnm="TPD2E007DCKR"),
+    )
+    asc = tmp_path / "netlist.asc"
+    asc.write_text(
+        "*PADS-PCB*\n*PART*\nU13 SOT23\nR1 0603\n*NET*\n"
+        "*SIGNAL* GND\nU13.1 R1.1\n*END*\n"
+    )
+    bom = tmp_path / "bom.csv"
+    bom.write_text("Reference,Value,PNM\nR1,10k,\n")
+    g = build_graph(
+        asc, bom, tmp_path / "ex", tmp_path / "pat", tmp_path / "mod",
+        mpn_col="Manufacturer Part Number",
+    )
+    assert g.components["U13"].mpn == "TPD2E007DCKR"
+