Fix backslash escaping in placeholder value escaping

restream/app/process.go

@@ -88,12 +88,13 @@ func replace(what, placeholder, value string) string {
 
 	what = re.ReplaceAllStringFunc(what, func(match string) string {
 		matches := re.FindStringSubmatch(match)
-		var v string
+		v := value
 
 		if matches[2] != "" {
-			v = strings.ReplaceAll(value, matches[2], `\`+matches[2])
-		} else {
-			v = value
+			if matches[2] != `\` {
+				v = strings.ReplaceAll(v, `\`, `\\`)
+			}
+			v = strings.ReplaceAll(v, matches[2], `\`+matches[2])
 		}
 
 		return strings.Replace(match, match, v, 1)

restream/app/process_test.go

@@ -7,21 +7,22 @@ import (
 )
 
 func TestReplace(t *testing.T) {
-	foobar := `;:.,-_$£!^`
+	foobar := `;:.,-_$\£!^`
 
 	samples := [][2]string{
 		{"{foobar}", foobar},
-		{"{foobar^:}", `;\:.,-_$£!^`},
-		{"{foobar^:}barfoo{foobar^:}", `;\:.,-_$£!^barfoo;\:.,-_$£!^`},
+		{"{foobar^:}", `;\:.,-_$\\£!^`},
+		{"{foobar^:}barfoo{foobar^:}", `;\:.,-_$\\£!^barfoo;\:.,-_$\\£!^`},
 		{"{foobar^:.}", "{foobar^:.}"},
 		{"{foobar^}", "{foobar^}"},
 		{"{barfoo^:}", "{barfoo^:}"},
-		{"{foobar^^}", `;:.,-_$£!\^`},
+		{"{foobar^^}", `;:.,-_$\\£!\^`},
+		{`{foobar^\}`, `;:.,-_$\\£!^`},
 	}
 
 	for _, e := range samples {
 		replaced := replace(e[0], "foobar", foobar)
-		require.Equal(t, e[1], replaced)
+		require.Equal(t, e[1], replaced, e[0])
 	}
 }