[Flouss]

Closes #135

Problem

A draft that arrives by sync (Outlook or Gmail) is listed in its conversation, but clicking it gives a 404: ComposeController::assertEditableDraft (the guard that only lets an unsent draft open) refuses anything with a sentAt, and every sync builder sets sentAt on a draft:

• Graph: sentAt = sentDateTime ?? receivedDateTime, and Outlook gives a draft a receivedDateTime but no sentDateTime.
• Gmail: sentAt = receivedAt from internalDate.
• IMAP: sentAt = receivedAt from the Date header.

Change

• The builders leave sentAt null for a draft, the same state a draft written in plMail has (receivedAt is unchanged). Documented on Message::$sentAt. The IMAP builder decides from the stored flag via isDraft(); webklex strips the backslash, so a real server's \Draft is stored as Draft and is not a draft to the app yet. That part does nothing until the flags are canonicalised at ingest, and is deliberately kept consistent with isDraft() instead.
• ReadReceiptPolicy::decide recognised our own mail by sentAt; it checks the draft flag as well now.

sentAt was also quietly protecting the other direction, which this PR has to handle: sync stores a draft once and never rebuilds a stored row, so a draft sent from another client stayed \Draft with no sentAt and would now open in the editor, be sendable a second time, and discarding it would delete the sent copy at the provider. Message::settleAsSent() is the one place that says what "was sent" means for a stored draft (flag off, keep an existing sentAt else now, thread ranked by it, never backwards). It is called when

• Graph files a stored message in Sent Items (same id, immutable ids),
• the Graph batch handler re-points a stored message whose fetched resource says isDraft: false (new id, no immutable ids; an absent key is not an answer),
• Gmail enrichment re-reads a stored draft whose labels have SENT and no DRAFT.

Trash and Drafts do not settle.

RemoteFlagState::storedFlags() rebuilt Gmail's and Graph's flag mirror from read and starred alone, which dropped \Draft the first time a stored draft was re-read, although the refresh's own comment says it survives. It now carries the flag over. This touches the shared flag refresh, so it deserves a look.

Notes

• Visible side effect (in the changelog): a conversation holding a synced draft is no longer moved up the list by the draft's date, the same as for a draft written in plMail.
• Drafts already stored are not migrated; their sent_at has to be cleared once (a single UPDATE on the affected rows).
• The send-elsewhere behaviour rests on two assumptions about the providers that the tests encode but that I have not observed against live Outlook or Gmail: Graph either keeps the id or re-fetches the sent copy with isDraft: false, and Gmail keeps the message id with DRAFT replaced by SENT.

Tests

Builder tests for all three providers, the sent-elsewhere paths (Graph same id, Graph new id, Gmail) each with a companion that must stay a draft, the settle method, the flag mirror, the editor opening a synced draft and still refusing a received mail, and the read-receipt guard. Each behaviour was broken on purpose and the test written for it failed. Full suite green except IntegrationUrlValidatorTest (container cannot resolve localhost.); phpstan clean on the changed files.

🤖 Generated with Claude Code

[karatektus]

Thanks, @Flouss! Your fork has been archived, so this branch can no longer be pushed to. Your work goes on in #164, which keeps your commits, merges main, and adds a migration for drafts stored before the upgrade (only ones the provider still files as drafts). You'll be credited as co-author when it's merged. Closing this one in its favour.