Add mail_send_draft: send the draft that was reviewed, not a copy of it

[rutgerhofste]

Closes the gap in Odoo task 928: Squirrel could write a draft and edit one, but not send it. The only way out was re-typing the draft's text into mail_send, which puts a second, subtly different message on the wire and leaves the reviewed one sitting in Drafts -- the duplicate the user finds afterwards.

The decision

mail_send_draft takes a uid and nothing else. A draft is already a complete RFC 5322 message, so rebuilding one from the arguments the tool layer models would quietly drop everything they do not: the multipart/related an embedded image lives in, the In-Reply-To that makes it a reply, a header another mail client wrote. What the user approved is what leaves.

How it is wired

• imap.fetch_outgoing hands the parsed message (plus its attachment filenames, off the same fetch) to smtp.send_existing.
• send_existing re-stamps exactly two headers: Date, because a draft's is when it was written and would sort the mail above what the recipient has already read; and a Message-ID when the draft has none (ours always do, another client's need not -- it is what the Sent copy is matched on).
• It then joins send's own _deliver_prepared, so the Bcc rule (on the Sent copy, off what leaves) and the SMTP SIZE check stay one path rather than two.
• provider.send_draft is the third thing only that class can do, after _reply_headers and _file_sent_copy: the message lives on the IMAP side and the wire is on the SMTP side.
• Removing the draft is last and, like the Sent copy, never fatal -- the mail is with the recipient by then, so a failure rides back as draft_removed=False rather than reporting a delivered message as undelivered and inviting a retry that sends it twice.
• The tool reads the capability as getattr(provider, "send_draft", None) and refuses with the alternative named, so a backend without it is told about rather than crashed into.

Tests

tests/test_send_draft.py (15 unit tests) pins the delivered bytes, the two re-stamped headers, the Bcc split, recipients coming from the draft's own headers, the never-fatal removal, and the tool's confirm gate + capability refusal. Two GreenMail e2e tests draft, send and then find the message in the inbox, in Sent, and gone from Drafts -- one of them with an attachment and a thread, proving nothing was rebuilt.

make test (252 passed) and make lint are green. make test-int was not run -- no Docker in this session, so the two new GreenMail tests are unverified against a real server.

Companion

pantalytics/squirrel-mcp-admin#78 adds the Graph half, so Outlook accounts get the same tool. It needs a SQUIRREL_MCP_REF bump to this commit once merged.

🤖 Generated with Claude Code

https://claude.ai/code/session_01K2DMxTXFL1aubHfjjEYCB6