net: do not modify shared test variable in TestDNSReadConfig

Fixes #56542

Change-Id: I294856f8fb4d49393310ec92ab40fb7d841b6570
GitHub-Last-Rev: a4563400af816caa6119775b7b01b51134c62149
GitHub-Pull-Request: golang/go#56545
Reviewed-on: https://go-review.googlesource.com/c/go/+/447198
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/net/dnsconfig_unix_test.go b/src/net/dnsconfig_unix_test.go
index 9be751f2e3e7c12c8ea91b977ed026355910f5f5..0aae2ba85b8c32377c55c01d5f18715846711597 100644 (file)
--- a/src/net/dnsconfig_unix_test.go
+++ b/src/net/dnsconfig_unix_test.go
@@ -176,16 +176,17 @@ func TestDNSReadConfig(t *testing.T) {
        getHostname = func() (string, error) { return "host.domain.local", nil }
 
        for _, tt := range dnsReadConfigTests {
-               if len(tt.want.search) == 0 {
-                       tt.want.search = append(tt.want.search, dnsDefaultSearch()...)
+               want := *tt.want
+               if len(want.search) == 0 {
+                       want.search = dnsDefaultSearch()
                }
                conf := dnsReadConfig(tt.name)
                if conf.err != nil {
                        t.Fatal(conf.err)
                }
                conf.mtime = time.Time{}
-               if !reflect.DeepEqual(conf, tt.want) {
-                       t.Errorf("%s:\ngot: %+v\nwant: %+v", tt.name, conf, tt.want)
+               if !reflect.DeepEqual(conf, &want) {
+                       t.Errorf("%s:\ngot: %+v\nwant: %+v", tt.name, conf, want)
                }
        }
 }
@@ -272,8 +273,13 @@ func TestDNSNameLength(t *testing.T) {
                        t.Fatal(conf.err)
                }
 
+               suffixList := tt.want.search
+               if len(suffixList) == 0 {
+                       suffixList = dnsDefaultSearch()
+               }
+
                var shortestSuffix int
-               for _, suffix := range tt.want.search {
+               for _, suffix := range suffixList {
                        if shortestSuffix == 0 || len(suffix) < shortestSuffix {
                                shortestSuffix = len(suffix)
                        }