ImapClient.deleteMessage and moveMessages flagged the target \Deleted then
called the untargeted Folder.expunge(), which permanently removes EVERY
\Deleted-flagged message in the folder — not just the intended UIDs. That is a
data-loss window whenever a second client, Gmail, or a partial earlier move has
left other messages flagged \Deleted. The repository's batch delete/expunge and
trash-fallback paths also looped single-UID deleteMessage, paying N logins + N
expunges for an N-message selection.
Add a batch deleteMessages(uids) that opens the folder once, flags the matched
messages \Deleted, and issues a single targeted UID EXPUNGE (RFC 4315) via
IMAPFolder.expunge(Message[]) through a shared expungeTargeted() helper. Route
moveMessages through the same helper, delegate single-UID deleteMessage to
deleteMessages, and route MailRepositoryImpl.expunge and the moveByRole trash
fallback through the batch method. moveToFolder already batches via moveMessages,
so it inherits the targeted expunge.
On a server without UIDPLUS, Angus raises "UID EXPUNGE not supported" rather than
silently falling back to the unrelated-mail-destroying untargeted expunge — a
loud failure is the safe outcome. Gmail, Outlook, and GreenMail all advertise
UIDPLUS.
Tests (GreenMail, no emulator): deleteMessages/moveMessages expunge only the
given UIDs and spare other \Deleted-flagged mail; a batch delete of three
messages opens exactly one connection and pays one LOGIN.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
JMR-devandClaude Opus 4.8
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