f7528b2 moved the five unit reads of apply_standard ahead of the style
stage so a refused read is a refusal with nothing written -- and then
decided the writes on those reads. Making a dimension style current
restores every DIM* variable from the style (ezdxf: _sync_header_to_dimstyle
on dimstyle_set_current; AutoCAD: ActiveDimStyle), so on a drawing whose
ISO-25/ANSI already carried another scale the gate read (1.0) equalled
the target, the DIMSCALE write was skipped and the drawing ended at the
style's scale while the report said `changed: {}` -- against the spec's
"LTSCALE 1, DIMSCALE 1" and the tool docstring. The pre-f7528b2 loop ran
after the switch and got this right; this is a regression of f7528b2.
The gate read stays (readable before anything is written); each variable
is read again after the style stage and the write is decided on that
value, so `changed` says what the write moved.
Measured on the running AutoCAD 2026 (25.1s, 2026-09-22, scratch
Documents.Add(), Close(False), real ComBackend after connect()):
ISO-25 modified to DIMSCALE 2.0 (dimstyle_modify -> {'DIMSCALE': [1.0, 2.0]}),
Annotative current, doc.GetVariable('DIMSCALE') -> 1.0
before: apply_standard(iso, layers=False)
-> {'changed': {}, 'applied': True}; ActiveDimStyle ISO-25;
doc.GetVariable('DIMSCALE') -> 2.0
after: -> {'changed': {'DIMSCALE': [2.0, 1.0]}, 'applied': True};
ActiveDimStyle ISO-25; doc.GetVariable('DIMSCALE') -> 1.0
ezdxf, same setup (dimstyle_create ISO-25 {DIMSCALE: 2.0}, Standard
current): before `{'INSUNITS': [6, 4]}` and DIMSCALE 2.0 afterwards;
after `{'INSUNITS': [6, 4], 'DIMSCALE': [2.0, 1.0]}` and DIMSCALE 1.0.
Tests: one regression per engine (both fail on the f7528b2 apply.py);
test_com_apply_standard_creates_both_styles_and_sets_units now pins the
gate reads first *and* the re-read-then-write sequence after CopyFrom,
instead of enshrining the stale-read order.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
