From 21751a4505f6647943f8751d4bda499d3aaef731 Mon Sep 17 00:00:00 2001
From: Daiderd Jordan <daiderd@gmail.com>
Date: Thu, 12 Apr 2018 22:32:30 +0200
Subject: [PATCH] fix warnings with rust 1.25.0

---
 ofborg/build.rs | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/ofborg/build.rs b/ofborg/build.rs
index 4881c36..58ca368 100644
--- a/ofborg/build.rs
+++ b/ofborg/build.rs
@@ -518,24 +518,27 @@ impl MetricCollector {
         .map(|mtype| {
             let fields: Vec<String> = mtype.enum_field_names();
 
-            let variant_match: String;
-            if fields.len() > 0 {
-                variant_match = format!("{}({})", &mtype.variant(), fields.join(", "));
+            let variant_match = if fields.len() > 0 {
+                format!("{}({})", &mtype.variant(), fields.join(", "))
             } else {
-                variant_match = format!("{}", &mtype.variant());
+                format!("{}", &mtype.variant())
+            };
+
+            let mut index_names: Vec<String> = mtype.enum_index_names();
+            index_names.push("instance".to_owned());
+
+            let mut index_fields = index_names.join(", ");
+            if index_names.len() > 1 {
+                index_fields = format!("({})", index_fields);
             }
 
-            let mut index_fields: Vec<String> = mtype.enum_index_names();
-            index_fields.push("instance".to_owned());
-
-
             format!("
       Event::{} => {{
         let mut accum_table = self.{}
           .lock()
           .expect(\"Failed to unwrap metric mutex for {}\");
         let accum = accum_table
-          .entry(({}))
+          .entry({})
           .or_insert(0);
         *accum += {};
       }}
@@ -543,7 +546,7 @@ impl MetricCollector {
                     variant_match,
                     &mtype.metric_name(),
                     &mtype.metric_name(),
-                    index_fields.join(", "),
+                    index_fields,
                     &mtype.record_value(),
             )
         }).collect();