Fix glob cache conflict when excludes=nil and excludes=[]string{}

Performing the same glob twice, once with excludes=nil and once
with excludes=[]string{} would hit the same entry in the glob
cache (since the glob filename would be the same), but fail
the verifyGlob check because DeepEqual considers []string(nil)
and []string{} to be different.  Use a manual array check
instead.

Test: glob_test.go
Change-Id: If0d4fe80163a871077b7276e1b4a3e888a4a4898

1 files changed, 7 insertions, 2 deletions

diff --git a/glob.go b/glob.go
index f3eb1b1..4553f69 100644
--- a/glob.go
+++ b/glob.go
@@ -17,7 +17,6 @@ package blueprint
 import (
 	"crypto/md5"
 	"fmt"
-	"reflect"
 	"sort"
 	"strings"
 )
@@ -34,9 +33,15 @@ func verifyGlob(fileName, pattern string, excludes []string, g GlobPath) {
 	if pattern != g.Pattern {
 		panic(fmt.Errorf("Mismatched patterns %q and %q for glob file %q", pattern, g.Pattern, fileName))
 	}
-	if !reflect.DeepEqual(g.Excludes, excludes) {
+	if len(excludes) != len(g.Excludes) {
 		panic(fmt.Errorf("Mismatched excludes %v and %v for glob file %q", excludes, g.Excludes, fileName))
 	}
+
+	for i := range excludes {
+		if g.Excludes[i] != excludes[i] {
+			panic(fmt.Errorf("Mismatched excludes %v and %v for glob file %q", excludes, g.Excludes, fileName))
+		}
+	}
 }
 
 func (c *Context) glob(pattern string, excludes []string) ([]string, error) {