From 7412e287742eb16501a188031f389cea329644a7 Mon Sep 17 00:00:00 2001
From: Stanislav Chzhen <s.chzhen@adguard.com>
Date: Fri, 17 Oct 2025 09:09:05 +0300
Subject: [PATCH] home: imp code

---
 internal/home/config.go | 39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/internal/home/config.go b/internal/home/config.go
index 5c0d4eab..d65dff77 100644
--- a/internal/home/config.go
+++ b/internal/home/config.go
@@ -626,7 +626,7 @@ func validateBindHosts(
 
 	for i, addr := range conf.DNS.BindHosts {
 		if !addr.IsValid() {
-			logIPv6Hint(ctx, l, fileData)
+			logIPHint(ctx, l, fileData)
 
 			return fmt.Errorf("dns.bind_hosts at index %d is not a valid ip address", i)
 		}
@@ -688,15 +688,10 @@ func parseConfig(ctx context.Context, l *slog.Logger) (err error) {
 	return validateTLSCipherIDs(config.TLS.OverrideTLSCiphers)
 }
 
-// hintIPv6 is printed when the "::" IPv6 address in the config is not quoted.
-const hintIPv6 = `NOTE:  Quote IPv6 addresses in 'dns.bind_hosts'.  For example:
-dns:
-  bind_hosts:
-    - '::'`
-
-// logIPv6Hint logs an informational message if the "::" IPv6 address in the
-// config is not quoted.
-func logIPv6Hint(ctx context.Context, l *slog.Logger, data []byte) {
+// logIPHint logs an informational message when the config contains an unquoted
+// IP address with a trailing colon.  It's a best-effort check for a YAML
+// parsing behavior where a list item is decoded as {key: null}.
+func logIPHint(ctx context.Context, l *slog.Logger, data []byte) {
 	var conf struct {
 		DNS struct {
 			BindHosts []any `yaml:"bind_hosts"`
@@ -706,7 +701,11 @@ func logIPv6Hint(ctx context.Context, l *slog.Logger, data []byte) {
 	err := yaml.Unmarshal(data, &conf)
 	if err != nil {
 		// This should not happen since this is already the validation process.
-		l.DebugContext(ctx, "failed to unmarshal the config to print ipv6 hint")
+		l.DebugContext(
+			ctx,
+			"failed to unmarshal config while logging ip hint",
+			slogutil.KeyError, err,
+		)
 
 		return
 	}
@@ -717,15 +716,27 @@ func logIPv6Hint(ctx context.Context, l *slog.Logger, data []byte) {
 			continue
 		}
 
-		v, ok := m[":"]
-		if !ok || v != nil {
+		if !hasNilValue(m) {
 			continue
 		}
 
-		slogutil.PrintLines(ctx, l, slog.LevelInfo, "", hintIPv6)
+		l.WarnContext(ctx, "quote addresses that end with a colon in 'dns.bind_hosts'")
+
+		return
 	}
 }
 
+// hasNilValue returns true if m contains a nil value.
+func hasNilValue(m map[string]any) (ok bool) {
+	for _, v := range m {
+		if v == nil {
+			return true
+		}
+	}
+
+	return false
+}
+
 // validateConfig returns error if the configuration is invalid.  l must not be
 // nil.
 func validateConfig(ctx context.Context, l *slog.Logger, fileData []byte) (err error) {