Gmail IMAP search by UID range seems to skip the first message

Question

I have a mailbox on gmail that has the following UIDs if I do a search 'ALL'.

[ 2, 5, 6, 51 ]

Oddly, if I do a search for '3:*', I only get [6, 51] back.

==> A6 UID SEARCH 3:*
<== '* SEARCH 6 51\r\nA6 OK SEARCH completed (Success)\r\n'
[parsing incoming] saw untagged SEARCH
<== 'A6 OK SEARCH completed (Success)\r\n'

From my understanding of IMAP, it is supposed to return [5, 6, 51] right? Is this a bug with Gmail or just my incorrect understandging?

Answer 1

You want UID SEARCH UID 3:*. You're searching by message sequence numbers. 1 -> 2, 2 -> 5, 3 -> 6, 4 -> 51. So you're searching for messages 3 and 4, which have UIDs 6, and 51.