Three review findings on the standards data layer, each a value the layer
let through that a backend would then write as a silent wrong number or a
drawing that can no longer be saved:
* validate_textstyle never checked math.isfinite, unlike its siblings; nan
and inf passed every comparison and reached the STYLE record verbatim.
It now has the same _number helper dimstyles and mleaderstyles use.
* The three private _ILLEGAL_NAME_CHARS copies omitted \n \r \t that
security._FORBIDDEN_SYMBOL_CHARS holds, so 'a\nb' was accepted as a text
style, DIMTXSTY or leader text style and ezdxf refused the save. The rule
now lives once in engineering/standards/names.py (fastmcp-free), the
three modules import it, and a test pins its character set equal to
security's and its output equal to illegal_symbol_name_chars.
* DIMBLK/DIMBLK1/DIMBLK2 were ("str",): any string went through, and the
test pinned '_OBLIQUE', which ezdxf's writer refuses at doc.write while
the COM engine wants exactly that spelling. They are now ("arrow",):
canonical_arrowhead accepts a built-in with or without its underscore in
any case (and '', '.', CLOSEDFILLED for the closed filled default), emits
AutoCAD's documented block-name spelling (also what ezdxf reports after a
load), and holds user block names to the symbol-name rule; ARROWHEAD_BLOCKS
is pinned equal to ezdxf's ARROWS vocabulary, and ezdxf_arrowhead is the
one translation the headless writer needs, proved by exporting all twenty
headlessly and reading each back as its canonical name.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
