From 07669f9eb40bffca762e159359e46cb6a13598f1 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Mon, 3 Feb 2025 21:13:57 -0500
Subject: [PATCH] remove hashset from mode parsing

---
 irc/handlers.go         |  6 +++---
 irc/modes.go            |  2 +-
 irc/modes/modes.go      | 14 ++++----------
 irc/modes/modes_test.go | 10 ++++++----
 4 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/irc/handlers.go b/irc/handlers.go
index 88890510..296a518b 100644
--- a/irc/handlers.go
+++ b/irc/handlers.go
@@ -1852,11 +1852,11 @@ func cmodeHandler(server *Server, client *Client, msg ircmsg.Message, rb *Respon
 	if 1 < len(msg.Params) {
 		// parse out real mode changes
 		params := msg.Params[1:]
-		var unknown map[rune]bool
+		var unknown []rune
 		changes, unknown = modes.ParseChannelModeChanges(params...)
 
 		// alert for unknown mode changes
-		for char := range unknown {
+		for _, char := range unknown {
 			rb.Add(nil, server.name, ERR_UNKNOWNMODE, client.nick, string(char), client.t("is an unknown mode character to me"))
 		}
 		if len(unknown) == 1 && len(changes) == 0 {
@@ -1943,7 +1943,7 @@ func umodeHandler(server *Server, client *Client, msg ircmsg.Message, rb *Respon
 		changes, unknown := modes.ParseUserModeChanges(params...)
 
 		// alert for unknown mode changes
-		for char := range unknown {
+		for _, char := range unknown {
 			rb.Add(nil, server.name, ERR_UNKNOWNMODE, cDetails.nick, string(char), client.t("is an unknown mode character to me"))
 		}
 		if len(unknown) == 1 && len(changes) == 0 {
diff --git a/irc/modes.go b/irc/modes.go
index e6079e24..cd7581ba 100644
--- a/irc/modes.go
+++ b/irc/modes.go
@@ -116,7 +116,7 @@ func ApplyUserModeChanges(client *Client, changes modes.ModeChanges, force bool,
 }
 
 // parseDefaultModes uses the provided mode change parser to parse the rawModes.
-func parseDefaultModes(rawModes string, parser func(params ...string) (modes.ModeChanges, map[rune]bool)) modes.Modes {
+func parseDefaultModes(rawModes string, parser func(params ...string) (modes.ModeChanges, []rune)) modes.Modes {
 	modeChangeStrings := strings.Fields(rawModes)
 	modeChanges, _ := parser(modeChangeStrings...)
 	defaultModes := make(modes.Modes, 0)
diff --git a/irc/modes/modes.go b/irc/modes/modes.go
index c9483bb4..fc902ceb 100644
--- a/irc/modes/modes.go
+++ b/irc/modes/modes.go
@@ -190,10 +190,7 @@ func GetLowestChannelModePrefix(prefixes string) (lowest Mode) {
 //
 
 // ParseUserModeChanges returns the valid changes, and the list of unknown chars.
-func ParseUserModeChanges(params ...string) (ModeChanges, map[rune]bool) {
-	changes := make(ModeChanges, 0)
-	unknown := make(map[rune]bool)
-
+func ParseUserModeChanges(params ...string) (changes ModeChanges, unknown []rune) {
 	op := List
 
 	if 0 < len(params) {
@@ -223,7 +220,7 @@ func ParseUserModeChanges(params ...string) (ModeChanges, map[rune]bool) {
 			if slices.Contains(SupportedUserModes, Mode(mode)) {
 				changes = append(changes, change)
 			} else {
-				unknown[mode] = true
+				unknown = append(unknown, mode)
 			}
 		}
 	}
@@ -232,10 +229,7 @@ func ParseUserModeChanges(params ...string) (ModeChanges, map[rune]bool) {
 }
 
 // ParseChannelModeChanges returns the valid changes, and the list of unknown chars.
-func ParseChannelModeChanges(params ...string) (ModeChanges, map[rune]bool) {
-	changes := make(ModeChanges, 0)
-	unknown := make(map[rune]bool)
-
+func ParseChannelModeChanges(params ...string) (changes ModeChanges, unknown []rune) {
 	op := List
 
 	if 0 < len(params) {
@@ -300,7 +294,7 @@ func ParseChannelModeChanges(params ...string) (ModeChanges, map[rune]bool) {
 			if slices.Contains(SupportedChannelModes, Mode(mode)) || slices.Contains(ChannelUserModes, Mode(mode)) {
 				changes = append(changes, change)
 			} else {
-				unknown[mode] = true
+				unknown = append(unknown, mode)
 			}
 		}
 	}
diff --git a/irc/modes/modes_test.go b/irc/modes/modes_test.go
index 67d28c2f..03f42c33 100644
--- a/irc/modes/modes_test.go
+++ b/irc/modes/modes_test.go
@@ -5,6 +5,7 @@ package modes
 
 import (
 	"reflect"
+	"slices"
 	"strings"
 	"testing"
 )
@@ -16,7 +17,7 @@ func assertEqual(supplied, expected interface{}, t *testing.T) {
 }
 
 func TestParseUserModeChanges(t *testing.T) {
-	emptyUnknown := make(map[rune]bool)
+	var emptyUnknown []rune
 	changes, unknown := ParseUserModeChanges("+i")
 	assertEqual(unknown, emptyUnknown, t)
 	assertEqual(changes, ModeChanges{ModeChange{Op: Add, Mode: Invisible}}, t)
@@ -48,10 +49,11 @@ func TestParseUserModeChanges(t *testing.T) {
 }
 
 func TestIssue874(t *testing.T) {
-	emptyUnknown := make(map[rune]bool)
+	var emptyModeChanges ModeChanges
+	var emptyUnknown []rune
 	modes, unknown := ParseChannelModeChanges("+k")
 	assertEqual(unknown, emptyUnknown, t)
-	assertEqual(modes, ModeChanges{}, t)
+	assertEqual(modes, emptyModeChanges, t)
 
 	modes, unknown = ParseChannelModeChanges("+k", "beer")
 	assertEqual(unknown, emptyUnknown, t)
@@ -151,7 +153,7 @@ func TestParseChannelModeChanges(t *testing.T) {
 	}
 
 	modes, unknown = ParseChannelModeChanges("+tx")
-	if len(unknown) != 1 || !unknown['x'] {
+	if len(unknown) != 1 || !slices.Contains(unknown, 'x') {
 		t.Errorf("expected that x is an unknown mode, instead: %v", unknown)
 	}
 	expected = ModeChange{