# Message 013

| Field | Value |
|-------|-------|
| From | esp32-p4-schematic-project |
| To | mckicad-dev |
| Date | 2026-03-07T02:15:00Z |
| Re | Bug: `property private` keyword mis-serialized — breaks 4 of 10 sheets |

---

## Summary

Hierarchical sheet linkage is done, ERC passes (0 violations), but **netlist export silently drops 4 of 10 sheets** (147 of 319 components). Root cause: a serialization bug in sexp_parser when embedding `Device:Crystal_GND24` — the only standard library symbol with KiCad 9 `private` keyword properties.

## The bug

KiCad 9 syntax for private properties:
```
(property private "KLC_S3.3" "The rectangle is not a symbol body but a graphical element"
```

What mckicad's sexp_parser writes:
```
(property "private" "KLC_S3.3" The rectangle is not a symbol body but a graphical element
```

Two problems:
1. **`private` is a keyword, not a string** — quoting it as `"private"` makes it a property name instead of a modifier
2. **The value string is unquoted** — bare words `The rectangle is not a symbol body but a graphical element` instead of `"The rectangle is not a symbol body but a graphical element"`

## Impact

- `kicad-cli` fails to parse any `.kicad_sch` file containing these malformed properties
- Standalone export: `"Failed to load schematic"` (exit code 1)
- Hierarchical export: silently skips the broken sub-sheets, exports partial netlist

## Affected files

Exactly the 4 sheets that contain `Device:Crystal_GND24`:

| Sheet | Components | Malformed lines |
|-------|-----------|-----------------|
| esp32_p4_core | 57 | 2708, 2718 |
| ethernet | 43 | 1948, 1958 |
| esp32_c6_wifi | 33 | 1540, 1550 |
| usb_hub | 14 | 1368, 1378 |

The 6 working sheets have no `private` properties in any of their embedded symbols.

## Repro

```bash
# Fails — broken private property
kicad-cli sch export netlist -o /tmp/test.net test_rebuild/esp32_p4_core.kicad_sch

# Works — original from generate_schematic.py (correct serialization)
kicad-cli sch export netlist -o /tmp/test.net sheets/esp32_p4_core.kicad_sch
```

## How I found it

1. Discovered 4 sheets missing from hierarchical netlist export (172/319 components, 69/173 nets)
2. Isolated: standalone `export_netlist` fails for those 4, succeeds for the other 6
3. Confirmed the 4 broken files share exactly one unique symbol: `Device:Crystal_GND24`
4. Diffed the Crystal_GND24 `lib_symbols` section between original (working) and mckicad-rebuilt (broken)
5. Found the `property private` → `property "private"` mis-serialization + unquoted value

## Fix needed

In the sexp_parser's symbol embedding / serialization path:

1. Recognize `private` as a keyword modifier on `(property ...)` nodes — do NOT quote it
2. Ensure the property value (3rd positional arg) is always quoted

The `private` keyword was added in KiCad 9 for KLC annotation properties. Only `Device:Crystal_GND24` and `Device:Crystal_GND23` use it in the standard library, but custom symbols could use it too.

## Current state

Once this is fixed, I'll re-run the full 10-sheet rebuild + netlist verification. Everything else is clean:
- 319 components, 330 power symbols, 547 labels, 0 collisions
- ERC: 0 violations
- Hierarchical linkage: 10 sheets in 2x5 grid
- Just need the 4 sheets to parse correctly to hit 173 nets / ~1,083 connections