because:
- shutdown_subdaemons can trigger db write, comments in that function say so at least
- resurrecting the main event loop with subdaemons still running is counter productive
in shutting down activity (such as htlc's, hook_calls etc.)
- custom behavior injected by plugins via hooks should be consistent, see test
in previous commmit
IDEA:
in shutdown_plugins, when starting new io_loop:
- A plugin that is still running can return a jsonrpc_request response, this triggers
response_cb, which cannot be handled because subdaemons are gone -> so any response_cb should be blocked/aborted
- jsonrpc is still there, so users (such as plugins) can make new jsonrpc_request's which
cannot be handled because subdaemons are gone -> so new rpc_request should also be blocked
- But we do want to send/receive notifications and log messages (handled in jsonrpc as jsonrpc_notification)
as these do not trigger subdaemon calls or db_write's
Log messages and notifications do not have "id" field, where jsonrpc_request *do* have an "id" field
PLAN (hypothesis):
- hack into plugin_read_json_one OR plugin_response_handle to filter-out json with
an "id" field, this should
block/abandon any jsonrpc_request responses (and new jsonrpc_requests for plugins?)
Q. Can internal (so not via plugin) jsonrpc_requests called in the main io_loop return/revive in
the shutdown io_loop?
A. No. All code under lightningd/ returning command_still_pending depends on either a subdaemon, timer or
plugin. In shutdown loop the subdaemons are dead, timer struct cleared and plugins will be taken
care of (in next commits).
fixup: we can only io_break the main io_loop once
5f69674faa