From 857cd690b022d912344392b673574d7a6fe2b716 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Tue, 30 Jun 2026 19:36:59 +0000
Subject: [PATCH 1/2] apply deferred fakelag immediately after execution

If the client sends a long multiline, then pauses on its own
before sending more data, we want to apply deferred fakelag
during the pause, rather than upon receiving the next input line.
---
 irc/client.go | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/irc/client.go b/irc/client.go
index c2b5fa30..a66798d0 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -263,10 +263,7 @@ func (s *Session) EndMultilineBatch(label string) (batch MultilineBatch, err err
 	// heuristics to estimate how much data they used while fakelag was suspended
 	fakelagBill := (batch.lenBytes / MaxLineLen) + 1
 	fakelagBillLines := (batch.message.LenLines() * 60) / MaxLineLen
-	if fakelagBill < fakelagBillLines {
-		fakelagBill = fakelagBillLines
-	}
-	s.deferredFakelagCount = fakelagBill
+	s.deferredFakelagCount = max(fakelagBill, fakelagBillLines)
 
 	if batch.label == "" || batch.label != label || !batch.message.ValidMultiline() {
 		err = errInvalidMultilineBatch
@@ -744,12 +741,7 @@ func (client *Client) run(session *Session) {
 		// XXX defer processing of command error parsing until after fakelag
 
 		if client.registered {
-			// apply deferred fakelag
-			for i := 0; i < session.deferredFakelagCount; i++ {
-				session.fakelag.Touch("")
-			}
-			session.deferredFakelagCount = 0
-			// touch for the current command
+			// apply fakelag
 			var command string
 			if err == nil {
 				command = msg.Command
@@ -797,6 +789,12 @@ func (client *Client) run(session *Session) {
 			go session.client.run(session)
 			break
 		}
+		// apply deferred fakelag immediately, so as to coincide with any delay imposed
+		// on the client side (avoiding double penalization)
+		for range session.deferredFakelagCount {
+			session.fakelag.Touch("")
+		}
+		session.deferredFakelagCount = 0
 	}
 }
 

From 8ec95e912a4e69bcf51cfcb46726163ea651e38d Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Tue, 30 Jun 2026 21:22:38 +0000
Subject: [PATCH 2/2] fix: don't close multiline batch twice

---
 irc/handlers.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/irc/handlers.go b/irc/handlers.go
index 74777dc7..e64d788c 100644
--- a/irc/handlers.go
+++ b/irc/handlers.go
@@ -592,6 +592,9 @@ func batchHandlerMultiline(server *Server, client *Client, msg ircmsg.Message, r
 				rb.Label = ""
 			}
 		}
+		if fail {
+			rb.session.EndMultilineBatch("")
+		}
 	} else if tag[0] == '-' {
 		batch, err := rb.session.EndMultilineBatch(tag[1:])
 		fail = (err != nil)
@@ -609,7 +612,6 @@ func batchHandlerMultiline(server *Server, client *Client, msg ircmsg.Message, r
 	}
 
 	if fail {
-		rb.session.EndMultilineBatch("")
 		if sendErrors {
 			rb.Add(nil, server.name, "FAIL", "BATCH", "MULTILINE_INVALID", client.t("Invalid multiline batch"))
 		}