Trigger account-hook when changing between mailboxes of different accounts

[thyssentishman]

Following a discussion about folder-hook vs account-hook on IRC, I'd like to suggest having the account-hook be triggered when changing between mailboxes of different accounts.

From the account-hook entry in the manual:

This hook works like folder-hook but is invoked whenever NeoMutt needs to access a remote mailbox (including inside the folder browser), not just when you open the mailbox.

The "not just" in the above sentence kind of implies that the account-hook is basically a folder-hook plus the extra stuff. However from reading the code base, I believe the account-hook is not actually triggered when changing between mailboxes, but only by the following events (might be incomplete):

1. When opening/adding the first mailbox of an account (IMAP, POP, NNTP). Subsequent additions don't seem to trigger it (with IMAP at least, POP and NNTP were not tested)
2. When finding a connection out of the list of connections
   • NNTP: When opening a connection to a server
   • POP: When fetching mail
   • SMTP: When sending a message
   • IMAP?

In a multi-account setup where unmailboxes * is used when switching between accounts this is perfectly enough, since on every switch the mailboxes of the account being switched to are opened and therefore the account-hook is triggered. However in other multi-account setups where unmailboxes * is not used and all mailboxes from all accounts are kept open, the account-hook is not triggered when switching accounts (that is when switching from e.g. mailbox account1/INBOX to account2/INBOX). A workaround is to rely on the folder hook, but then the hook is unnecessarily triggered even when switching between mailboxes of the same account and we lose the other benefits of the account hook. Another option is to call the account hook when changing between any mailboxes, but then it would pretty much do everything the folder hook does and more, making the folder hook redundant. The only alternative that I think makes sense and allows for both the folder and account hook to coexist, is to also trigger the account hook when changing between mailboxes of different accounts.

I'd very much like to help implement this. I think it should be as trivial as comparing the current and new mailbox and checking if the accounts they belong to match or not. If not, then we call the account-hook here. I've started fiddling with the code already, but I'm unsure about how to go about differentiating between accounts purely based on the mailbox. For imap mailboxes, comparing host urls should be enough, but for other/local mailboxes?

[thyssentishman]

Would parsing $folder from both mailboxes' realpath be enough?

[thyssentishman]

What about something like this:

diff --git a/index/dlg_index.c b/index/dlg_index.c
index 4bb52760f..dcd1213dd 100644
--- a/index/dlg_index.c
+++ b/index/dlg_index.c
@@ -672,6 +672,10 @@ void change_folder_mailbox(struct Menu *menu, struct Mailbox *m, int *oldcount,
   char *dup_path = mutt_str_dup(mailbox_path(m));
   char *dup_name = mutt_str_dup(m->name);
 
+  const char *const c_folder = cs_subset_string(shared->sub, "folder");
+  if (!mutt_regex_match(mutt_regex_new(c_folder, 0, NULL), dup_path))
+    mutt_account_hook(dup_path);
+
   mutt_folder_hook(dup_path, dup_name);
   if (m)
   {

This compares the $folder from the current mailbox with $folder from the mailbox we are changing to. If they don't match, we perform the account-hook. It seems to work great with two IMAP and two local (Maildir) accounts I tested. Adding this would simplify a multi-account setup that does not use unmailboxes * when switching accounts to a config like the following:

# $XDG_CONFIG_HOME/neomutt/neomuttrc
# Last sourced account is startup account

source "$XDG_CONFIG_HOME/neomutt/accounts/account_1"
source "$XDG_CONFIG_HOME/neomutt/accounts/account_2"

# $XDG_CONFIG_HOME/neomutt/accounts/{account_1,account_2}

set folder = "<imap-server>"

account-hook $folder "set folder = $folder; \
		set imap_user = <imap-user>; \
		set imap_pass = <imap-passwd>; \
		set smtp_user = <smtp-user>; \
		set smtp_pass = <smtp-passwd>; \
		set smtp_url = <smtp-server>; \
		set from = <email>; \
		set spool_file = +INBOX; \
		set record = +Sent; \
		set trash = +Trash; \
		set postponed = +Drafts; \
		set signature = $XDG_CONFIG_HOME/neomutt/signature; \
		alternates <email-2>"

mailboxes +INBOX +Archive +Drafts +Sent +Trash +Junk

Multi-account setups using unmailboxes * should not be affected.