The endpoint that receives the user's Google OAuth credentials file had
no tests. Two bugs surfaced.
The OAuth-shape check ran inside `except Exception: pass`. A JSON
document that parses but is not an object — a bare 42, true, null, a
list — makes `'installed' not in creds_data` raise TypeError, which the
bare except swallowed, and the file was then written out as
credentials.json regardless. The check now decides the outcome instead
of being advisory, so anything not credentials-shaped is refused up
front rather than failing later inside the calendar plugin.
Every overwrite copies the old file to credentials.json.backup.<ts> and
nothing removed them, so a user who re-uploaded ten times had ten
complete sets of OAuth client credentials sitting in the plugin
directory, indefinitely. Keep the newest five. Pruning is housekeeping,
so a backup that cannot be removed logs and leaves the upload alone.
27 tests: size and extension limits, malformed JSON, the shape check,
0600 permissions on the written file, backup-on-overwrite, and pruning
including the repeated-upload case that stays bounded.
Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NohXi78cwsAKtN1sCfxjUh
