caddyfile: fix env var expansion after Go template (#2304)

caddyfile/parse.go

@@ -424,7 +424,12 @@ func replaceEnvVars(s string) string {
 func replaceEnvReferences(s, refStart, refEnd string) string {
 	index := strings.Index(s, refStart)
 	for index != -1 {
-		endIndex := strings.Index(s, refEnd)
+		endIndex := strings.Index(s[index:], refEnd)
+		if endIndex == -1 {
+			break
+		}
+
+		endIndex += index
 		if endIndex > index+len(refStart) {
 			ref := s[index : endIndex+len(refEnd)]
 			s = strings.Replace(s, ref, os.Getenv(ref[len(refStart):len(ref)-len(refEnd)]), -1)

caddyfile/parse_test.go

@@ -526,6 +526,13 @@ func TestEnvironmentReplacement(t *testing.T) {
 	if actual, expected := blocks[0].Tokens["dir1"][1].Text, "Test foobar test"; expected != actual {
 		t.Errorf("Expected argument to be '%s' but was '%s'", expected, actual)
 	}
+
+	// after end token
+	p = testParser(":1234\nanswer \"{{ .Name }} {$FOOBAR}\"")
+	blocks, _ = p.parseAll()
+	if actual, expected := blocks[0].Tokens["answer"][1].Text, "{{ .Name }} foobar"; expected != actual {
+		t.Errorf("Expected argument to be '%s' but was '%s'", expected, actual)
+	}
 }
 
 func testParser(input string) parser {