commit 3640c57a48eaf002ca5d5465ef7dac29310631a4
author Maxime Soulé <zeptomax@gmail.com> Tue Oct 11 14:25:48 2022 +0000
committer Gopher Robot <gobot@golang.org> Wed Oct 12 13:45:08 2022 +0000
tree 3601cbab0be9cbc37f7fce4e6ab155346a67b413
parent 59b0eab1532e130b420c72530677481d49c34f13

jsonrpc2: initialize Connection.async before calling binder.Bind

If Connection.async is not initialized before calling binder.Bind()
and a goroutine is spawned in binder.Bind() to monitor the end of the
connection using conn.Wait(), this conn.Wait() can wait forever:

    func (s *MyServer) Bind(
        ctx context.Context,
        conn *jsonrpc2.Connection,
    ) (jsonrpc2.ConnectionOptions, error) {
        // XXX register conn in *MyServer

        // monitor the end of the connection
        go func() {
            conn.Wait()
            conn.Close()
            // YYY do some cleanup in *MyServer
        }()
        return jsonrpc2.ConnectionOptions{}, nil
    }

The "// YYY do some cleanup in *MyServer" should be reached for each
end of connection.

If Connection.async is initialized too late, after conn.Wait() is
called in the Bind() spawned goroutine, conn.Wait() never returns as
it reads on a nil conn.async.ready channel.

Fixes #56131.

Change-Id: I3c6e69d7dcc860479c4518ebd18e2431606322bc
GitHub-Last-Rev: a7fce452df55a8dd113790d00097c37db454eb3b
GitHub-Pull-Request: golang/exp#45
Reviewed-on: https://go-review.googlesource.com/c/exp/+/436888
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Joedian Reid <joedian@golang.org>