aeab950 claimed one registry entry per file but only the two save paths
compared with normcase. _register_document keyed by the plain
os.path.abspath string, so on Windows drawing_open of an already-open
file spelled with another case registered a second entry (no `reloaded`,
open_documents: 2); from there every document_activate/close of either
entry was refused as ambiguous, and drawing_close(save=True) — which
bypasses the resolver — wrote the second entry's bytes to the shared
file while the surviving row reported saved: True. The resolver's
by_path route had the same plain-string comparison, so over the wire a
lowercase drive letter was refused 'no open document named ...' while
ComBackend._com_find_document lowercases and accepts it.
One helper, _file_identity(path) = normcase(abspath(path)), now decides
every registry comparison: _register_document consults _path_holder so
another spelling of an open file reloads it; the _doc_path setter re-keys
only when the file changes, so a case-variant save keeps the key a caller
holds; _resolve_document_key's by_path compares identities;
_close_document_sync refuses at the write when another entry holds the
file; _clear_quarantine's same-path warning uses the same rule. Keys stay
spelled as the caller spelled them — the identity is for comparing, not
for showing.
Five tests pin it (four skip on a case-sensitive filesystem, where two
spellings of one file cannot exist), including the wire route through
fastmcp.Client that the review measured.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
