imap: fix error with empty flag updates

Fix the following error occurring when fetching new headers after IDLE:

 panic: runtime error: invalid memory address or nil pointer dereference

 bufio.(*Reader).fill(0xc00029af00)
         bufio/bufio.go:106 +0xd8
 bufio.(*Reader).Peek(0xc0006e1f00, 0x1)
         bufio/bufio.go:144 +0x5d
 github.com/emersion/go-message/textproto.ReadHeader(0x0?)
         github.com/emersion/go-message@v0.15.0/textproto/header.go:525 +0x5f
 git.sr.ht/~rjarry/aerc/worker/imap.(*IMAPWorker).handleFetchMessageHeaders.func1(0xc00026e980)
         git.sr.ht/~rjarry/aerc/worker/imap/fetch.go:49 +0x1ab
 git.sr.ht/~rjarry/aerc/worker/imap.(*IMAPWorker).handleFetchMessages.func1()
         git.sr.ht/~rjarry/aerc/worker/imap/fetch.go:222 +0xa2
 created by git.sr.ht/~rjarry/aerc/worker/imap.(*IMAPWorker).handleFetchMessages
         git.sr.ht/~rjarry/aerc/worker/imap/fetch.go:217 +0x10a

Some IMAP messages only contain flag updates, ignore them.

Reuse the same logic than handleFetchMessageBodyPart() and
handleFechFullMessages().

Fixes: https://todo.sr.ht/~rjarry/aerc/111
Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: normen <normenweb@mac.com>

0 files changed, 0 insertions, 0 deletions