On the live engine, take_snapshot read a .dwg path by calling
Documents.Open(path, read-only), exporting and then Close(False) on what
Open returned. If the operator already had that drawing open, that was
their document, and closing it unsaved could throw away unsaved work.
drawing_understand, drawing_scale_check, drawing_diff and the takeoffs all
read a path through this function.
The review of drawing_diff raised the risk and did not probe it live, to
avoid a modal dialog on the shared AutoCAD. The fix makes the question
moot: the path is looked up among the open documents first, case-blind as
Windows paths are, and an open drawing is exported as it stands (unsaved
edits included) and left open. Only a document opened here is closed here.
The new test, against the fake that behaves as measured, fails on the old
code with an open and a close in the log.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
