Two review findings, both root causes.
1. `_sync_header_to_dimstyle` copied the DIMSTYLE entry's ezdxf-internal
arrowhead spelling (OBLIQUE) into the DXF-facing $DIMBLK/$DIMBLK1/$DIMBLK2
header, so the saved file named a block it did not hold (the blocks are
_OBLIQUE / _DOT) and `system_get_variable("DIMBLK")` answered "OBLIQUE"
headlessly against "_OBLIQUE" on COM and in the same engine's own
`dimstyle_list` row. The header write now goes through
`reported_arrowhead` — the same read-side rule `_dimstyle_value` applies.
Pinned by header, `system_get_variable`, save/reopen (`ezdxf.readfile`
header equals the block the file holds) and the Restore-to-Standard
empty-string case in `test_builtin_arrowheads_render_save_and_report_one_spelling`.
2. The `mleaderstyle` capability refusal rested on a false engine boundary.
acax25enu.tlb (AutoCAD 2026) exposes IAcadMLeaderStyle with Name,
ArrowSize, LandingGap, TextHeight, TextStyle, ... — exactly what
`Dictionaries.Item("ACAD_MLEADERSTYLE").Item(i)` returns — and
IAcadDictionary.AddObject(keyword, "AcDbMLeaderStyle") creates one.
COM `mleaderstyle_list` now reads the four values off those objects
(`values_available: True`); COM `mleaderstyle_create` validates every value
(`validate_mleaderstyle`, shared with ezdxf), checks the clash and the text
style before AddObject, then writes the four properties. The contract
method is `@abstractmethod` again, the key is gone from both capability
maps, the fake ActiveX surface models the real call shape, and the spec
(§4.2, §8.1, §9) states the ActiveX route.
Live AutoCAD was not running on this machine (GetActiveObject: operation
unavailable; no acad.exe), so the COM route is type-library-verified and
fake-tested, not executed live — scripts/smoke_settings_com.py (Task 24)
owns that.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
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 $DIMDSEP / group 278 as 128512, outside the 16-bit
range and refused by AutoCAD as "not a single character". ezdxf's audit
caught none of it. The same hole 827719f closed for names and fonts, left
open for the one variable stored as a character code.
The gate now refuses code < 32, DEL, and code > DIMDSEP_MAX_CODE (0x7FFF,
the signed short DWG stores) with a ValueError naming DIMDSEP, so nothing
reaches a backend. Pinned by a parametrized refusal test (newline, tab, NUL,
DEL, U+1F600, U+8000, U+FFFF), a positive test that the middle dot, the
Arabic decimal separator and U+7FFF still pass, and the ezdxf refusal test
now proves dimstyle_create / dimstyle_modify write nothing for these.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
Three headless defects in the styles block, each measured before the fix:
* `_normalise_dimstyle_rounding` cleaned `Standard` only, while ezdxf's
exporter writes DIMRND 0.0 for every DIMSTYLE. A user style (ISO-25 / ANSI)
came back from save/open, transaction_rollback and drawing_undo rounding
every dimension to a whole unit ("33" for 33.333, "R6" for R6.35) with
dimstyle_list still reporting DIMDEC 2. It now walks the whole table.
* `drawing_purge` followed only entity `.dxf.style`, so it deleted the text
style a DIMSTYLE (DIMTXSTY), an MLEADERSTYLE (text_style_handle) or the
header ($TEXTSTYLE / $DIMTXSTY) referenced; the next dimension silently
rendered in Standard and drawing_save_as raised DXFTableEntryError after
leaving a truncated file. `_style_table_references` now counts those, plus
the arrowhead blocks a DIMSTYLE / MLEADERSTYLE / MULTILEADER references,
compared case-insensitively.
* `_sync_header_to_dimstyle` wrote only the attributes the target style
stores, leaving the previous style's $DIM* in the header — folded onto the
next dimension by `_with_header_dimvars` (ISO-25 DIMZIN 0 / DIMSCALE 2.0
then Restore Standard rendered 5.0 mm "33.30") and written to the file as
current-style overrides; $DIMRND 0.5 outlived the style's own discard. It
now writes the schema default for every whitelist variable the style omits
(`Standard` for DIMTXSTY), which reproduces a fresh header exactly.
tests/test_styles.py: the reopen test now renders a dimension after the
reopen, plus one test per defect; all four fail on the previous backend.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
