An ISA-5.1 signal line has no pipe line number, yet every pneumatic /
electric line got the bare sequence as its number and a label, and ate a
process sequence number. Signal classes now leave line_number None (a
verbatim one is still honoured), seq None, no label. A radial port aimed
at the far end even with waypoints, so the first segment cut through the
bubble; aim_points (lines.py) aims at the first/last waypoint for both
draw_line and the dry run.
Merge note: benchmarks/adapters/autocad_mcp_pro.py (final group's file)
had its two _task_pid_roundtrip assertion lines moved to the new truth —
the signal row is unnumbered, the connector row is 3.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
Three ways `engineering/pid/lines.py` could emit a silent wrong result or
an opaque crash instead of an honest refusal:
- `format_line_number` only recognised a token that was exactly `{field}`;
`P-{seq:04d}`, `{size}"-{service}` or `{bogus}x` were copied verbatim,
braces and all, into the line number. Tokens are now parsed with
`string.Formatter`: one named known field per token, a format spec is
honoured (`{seq:04d}` -> `0007`), literal decoration around the field
survives with it and drops out with it, and conversions, positional
fields, multi-field tokens, unbalanced braces and specs the value cannot
take are all refused by token name.
- `route` never checked finiteness: a NaN `end` collapsed the U candidate
to a valid two-point "straight" path ending at the stub point. Every
coordinate of start/end/waypoints and the stub are now checked and the
refusal names the offending `end.x` / `waypoints[1].y` / stub.
- A non-axis port direction (45.0, 90.5, nan) raised `KeyError` from the
AXIS lookup. `axis_direction()` now normalises with a 1e-6 deg tolerance
for engine drift and otherwise raises ValueError naming `start_dir` /
`end_dir` and how to resolve it (rotate to a multiple of 90 or pass
waypoints).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
