Hi all, I would like to inform the devs that I discovered an iCloud server issue that affects many email clients (including all currently using MailCore2) and causes them to crash or not synchronize properly when used with iCloud IMAP accounts.
For an example of this issue in a client utilizing MailCore2, see The Eternal Sync Bug
Issue description
In short, some messages in iCloud's IMAP reply to an UID FETCH request contain ENVELOPE's that have a Message-ID containing unescaped double quotes. This causes the parser to fault and the fetch command to fail.
This in turn results in some clients crashing or getting stuck in the synchronization process because they keep retrying the UID FETCH and it keeps faling.
Solution
The issue is on Apple's side and should ideally be fixed by them. I've opened an issue with Apple to this end but their track record responding to these is not great.
In the mean while, I implemented a workaround in libetpan, which is used by MailCore2 to communicate with IMAP servers. This workaround should provide a temporary reolsution of the issue until Apple fixes it on their side.
The workaround still needs to be accepted by the people responsible for maintaining libetpan though, and will require that MailCore2 integrates this new version of libetpan and in turn requires email client authors to update their MailCore2 to that version. I hope I can get this going asap.
Summary
Hi all, I would like to inform the devs that I discovered an iCloud server issue that affects many email clients (including all currently using
MailCore2) and causes them to crash or not synchronize properly when used with iCloud IMAP accounts.For an example of this issue in a client utilizing
MailCore2, see The Eternal Sync BugIssue description
In short, some messages in iCloud's IMAP reply to an
UID FETCHrequest containENVELOPE's that have aMessage-IDcontaining unescaped double quotes. This causes the parser to fault and the fetch command to fail.This in turn results in some clients crashing or getting stuck in the synchronization process because they keep retrying the
UID FETCHand it keeps faling.Solution
The issue is on Apple's side and should ideally be fixed by them. I've opened an issue with Apple to this end but their track record responding to these is not great.
In the mean while, I implemented a workaround in
libetpan, which is used byMailCore2to communicate with IMAP servers. This workaround should provide a temporary reolsution of the issue until Apple fixes it on their side.See: https://github.com/dinhvh/libetpan/issues/426
The workaround still needs to be accepted by the people responsible for maintaining
libetpanthough, and will require thatMailCore2integrates this new version oflibetpanand in turn requires email client authors to update their MailCore2 to that version. I hope I can get this going asap.