check_dim_value's char branch only checked len == 1, so '\n', '\t', '\x00'
and non-BMP characters passed and the headless writer stored ord(value)
unguarded: '\n' split the dimension text over two lines, NUL read back as a
comma, and U+1F600 reached $DIMDSEP / group 278 as 128512, outside the 16-bit
range and refused by AutoCAD as "not a single character". ezdxf's audit
caught none of it. The same hole 827719f closed for names and fonts, left
open for the one variable stored as a character code.
The gate now refuses code < 32, DEL, and code > DIMDSEP_MAX_CODE (0x7FFF,
the signed short DWG stores) with a ValueError naming DIMDSEP, so nothing
reaches a backend. Pinned by a parametrized refusal test (newline, tab, NUL,
DEL, U+1F600, U+8000, U+FFFF), a positive test that the middle dot, the
Arabic decimal separator and U+7FFF still pass, and the ezdxf refusal test
now proves dimstyle_create / dimstyle_modify write nothing for these.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
