From ac2f39e987c8865e5faff2115880fa95622939af Mon Sep 17 00:00:00 2001
From: Kyle Brandt <kyle@kbrandt.com>
Date: Wed, 16 Mar 2016 12:28:56 -0400
Subject: [PATCH] cmd/bosun: Fix merge to error on duplicate groups

also, no stack trace on errors.
---
 cmd/bosun/expr/expr.go       |  5 ++--
 cmd/bosun/expr/funcs.go      |  6 ++--
 cmd/bosun/expr/funcs_test.go | 54 ++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 5 deletions(-)

diff --git a/cmd/bosun/expr/expr.go b/cmd/bosun/expr/expr.go
index b645a16b7a..f67b6f7f37 100644
--- a/cmd/bosun/expr/expr.go
+++ b/cmd/bosun/expr/expr.go
@@ -128,13 +128,14 @@ func (e *Expr) ExecuteState(s *State, T miniprofiler.Timer) (r *Results, queries
 func errRecover(errp *error) {
 	e := recover()
 	if e != nil {
-		slog.Infof("%s: %s", e, debug.Stack())
 		switch err := e.(type) {
 		case runtime.Error:
+			slog.Infof("%s: %s", e, debug.Stack())
 			panic(e)
 		case error:
 			*errp = err
 		default:
+			slog.Infof("%s: %s", e, debug.Stack())
 			panic(e)
 		}
 	}
@@ -293,7 +294,7 @@ func (a *Results) Equal(b *Results) (bool, error) {
 			}
 		case Series:
 			if !t.Equal(sortedB[i].Value.(Series)) {
-				return false, fmt.Errorf("mismatched series in result a: %v, b: %v", t, sortedB[i].Value.(Series))
+				return false, fmt.Errorf("mismatched series in result (Group: %s) a: %v, b: %v", result.Group, t, sortedB[i].Value.(Series))
 			}
 		default:
 			panic(fmt.Sprintf("can't compare results with type %T", t))
diff --git a/cmd/bosun/expr/funcs.go b/cmd/bosun/expr/funcs.go
index 49253212fd..e10a31aa93 100644
--- a/cmd/bosun/expr/funcs.go
+++ b/cmd/bosun/expr/funcs.go
@@ -471,15 +471,15 @@ func Filter(e *State, T miniprofiler.Timer, series *Results, number *Results) (*
 }
 
 func Merge(e *State, T miniprofiler.Timer, series ...*Results) (*Results, error) {
+	res := &Results{}
 	if len(series) == 0 {
-		return &Results{}, fmt.Errorf("merge requires at least one result")
+		return res, fmt.Errorf("merge requires at least one result")
 	}
 	if len(series) == 1 {
 		return series[0], nil
 	}
-	res := series[0]
 	seen := make(map[string]bool)
-	for _, r := range series[1:] {
+	for _, r := range series {
 		for _, entry := range r.Results {
 			if _, ok := seen[entry.Group.String()]; ok {
 				return res, fmt.Errorf("duplicate group in merge: %s", entry.Group.String())
diff --git a/cmd/bosun/expr/funcs_test.go b/cmd/bosun/expr/funcs_test.go
index 91cb26b440..49cfe24e82 100644
--- a/cmd/bosun/expr/funcs_test.go
+++ b/cmd/bosun/expr/funcs_test.go
@@ -1,9 +1,12 @@
 package expr
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
+	"bosun.org/opentsdb"
+
 	"github.com/influxdata/influxdb/client"
 )
 
@@ -60,3 +63,54 @@ func TestToDuration(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestMerge(t *testing.T) {
+	seriesA := `series("foo=bar", 0, 1)`
+	seriesB := `series("foo=baz", 0, 1)`
+	err := testExpression(exprInOut{
+		fmt.Sprintf("merge(%v, %v)", seriesA, seriesB),
+		Results{
+			Results: ResultSlice{
+				&Result{
+					Value: Series{
+						time.Unix(0, 0): 1,
+					},
+					Group: opentsdb.TagSet{"foo": "bar"},
+				},
+                &Result{
+					Value: Series{
+						time.Unix(0, 0): 1,
+					},
+					Group: opentsdb.TagSet{"foo": "baz"},
+				},
+			},
+		},
+	})
+    if err != nil {
+        t.Error(err)
+    }
+    
+    //Should Error due to identical groups in merge
+    err = testExpression(exprInOut{
+		fmt.Sprintf("merge(%v, %v)", seriesA, seriesA),
+		Results{
+			Results: ResultSlice{
+				&Result{
+					Value: Series{
+						time.Unix(0, 0): 1,
+					},
+					Group: opentsdb.TagSet{"foo": "bar"},
+				},
+                &Result{
+					Value: Series{
+						time.Unix(0, 0): 1,
+					},
+					Group: opentsdb.TagSet{"foo": "bar"},
+				},
+			},
+		},
+	})
+    if err == nil {
+        t.Errorf("error expected due to identical groups in merge but did not get one")
+    }
+}