get_hermes_dir(new_subpath, old_name) returned the legacy <old_name>/
location as soon as it existed on disk — even when empty. When an empty
legacy stub is created on a profile that already has populated data at
the new consolidated <new_subpath>/ (install scaffolds, profile init, a
stray mkdir, or ensure_hermes_home() recreating legacy dirs), the
resolver silently flipped to the empty legacy dir and the real data
became invisible. No log, no error — the feature behaved as if state was
wiped. Reproduced as a Discord pairing store losing every approved user
when an empty pairing/ shadowed the populated platforms/pairing/.
Resolve the legacy path only when it has content: a populated directory
(any entry) or a non-directory file counts; an empty directory falls
through to the new layout. Inspection failures (PermissionError on
lstat/iterdir, or any OSError short of FileNotFoundError) are treated as
"occupied" so a transient error never orphans legacy data — only a
genuine FileNotFoundError counts as absent. The lstat()-based gate also
fixes the prior exists()/is_dir() path swallowing PermissionError and
mis-reading an unreadable legacy dir as absent.
This hardens all 11+ call sites that share the resolver (pairing,
image/audio/video/document caches, matrix/whatsapp session stores,
vision/credential/tts/browser dirs).
Adds TestGetHermesDir regression coverage (empty/populated/subdir/file/
unreadable/unstatable cases) and updates test_credential_files to
populate its legacy dirs so they still count as content.
Closes#27602Closes#27715
briandevans
2d8c44ac87