sigil-irc-websocket: document the genuine-close invariant in irc-ws-receive

Message

irc-ws-receive latches the session 'disconnected only on a genuine 'closed; that relies on (sigil websocket) ws-receive returning #f (not 'closed) while a browser socket is still in its async CONNECTING window. Comment-only; no behavior change.

Changed

 packages/sigil-irc-websocket/src/sigil/irc/websocket.sgl | 8 ++++++++
 1 file changed, 8 insertions(+)

Diff

packages/sigil-irc-websocket/src/sigil/irc/websocket.sglmodified

@@ -577,6 +577,14 @@

577

(enqueue-message! session (ws-message-data message))

578

(pop-message! session))

579

#f))

+580

;; Latch the session dead ONLY on a genuine close. This

+581

;; relies on ws-receive returning #f (not 'closed) while a

+582

;; browser socket is still in its async CONNECTING window

+583

;; — otherwise the first poll during that window would

+584

;; kill a connection that is merely opening slowly (the

+585

;; browser slow-open bug fixed in (sigil websocket)

+586

;; ws-receive). Do not relax that invariant without

+587

;; distinguishing connecting from closed here too.

588

((eq? message 'closed)

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(set-irc-ws-session-state! session 'disconnected)

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'closed)