From d26559316fa6fae880351637365f07947a2b79f6 Mon Sep 17 00:00:00 2001
From: Chirag Maheshwari <34106488+chir4gm@users.noreply.github.com>
Date: Sun, 7 Aug 2022 09:33:37 +0530
Subject: [PATCH] Replace strings.Index with strings.Cut (#4932)

---
 cmd/main.go                                    | 7 ++-----
 modules/caddyhttp/reverseproxy/reverseproxy.go | 4 ++--
 modules/caddyhttp/rewrite/rewrite.go           | 4 ++--
 3 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/cmd/main.go b/cmd/main.go
index c475eaad..09246f4b 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -408,11 +408,8 @@ func parseEnvFile(envInput io.Reader) (map[string]string, error) {
 		}
 
 		// remove any trailing comment after value
-		if commentStart := strings.Index(val, "#"); commentStart > 0 {
-			before := val[commentStart-1]
-			if before == '\t' || before == ' ' {
-				val = strings.TrimRight(val[:commentStart], " \t")
-			}
+		if commentStart, _, found := strings.Cut(val, "#"); found {
+			val = strings.TrimRight(commentStart, " \t")
 		}
 
 		// quoted value: support newlines
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index c800b390..8887511e 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -658,8 +658,8 @@ func (h Handler) addForwardedHeaders(req *http.Request) error {
 
 	// Client IP may contain a zone if IPv6, so we need
 	// to pull that out before parsing the IP
-	if idx := strings.IndexByte(clientIP, '%'); idx >= 0 {
-		clientIP = clientIP[:idx]
+	if before, _, found := strings.Cut(clientIP, "%"); found {
+		clientIP = before
 	}
 	ip := net.ParseIP(clientIP)
 	if ip == nil {
diff --git a/modules/caddyhttp/rewrite/rewrite.go b/modules/caddyhttp/rewrite/rewrite.go
index ac8c4fc6..7da23277 100644
--- a/modules/caddyhttp/rewrite/rewrite.go
+++ b/modules/caddyhttp/rewrite/rewrite.go
@@ -194,10 +194,10 @@ func (rewr Rewrite) Rewrite(r *http.Request, repl *caddy.Replacer) bool {
 
 		// before continuing, we need to check if a query string
 		// snuck into the path component during replacements
-		if quPos := strings.Index(newPath, "?"); quPos > -1 {
+		if before, after, found := strings.Cut(newPath, "?"); found {
 			// recompute; new path contains a query string
 			var injectedQuery string
-			newPath, injectedQuery = newPath[:quPos], newPath[quPos+1:]
+			newPath, injectedQuery = before, after
 			// don't overwrite explicitly-configured query string
 			if query == "" {
 				query = injectedQuery