syscall: sort Windows env block in StartProcess

Fixes #29530

Change-Id: Ia28c78274b9288bfa5de9ccb142a452d291a5b66
Reviewed-on: https://go-review.googlesource.com/c/go/+/694435
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Joseph Tsai <joetsai@digital-static.net>
Auto-Submit: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/src/syscall/exec_windows_test.go b/src/syscall/exec_windows_test.go
index 90a13af8d1..60a995e4e7 100644
--- a/src/syscall/exec_windows_test.go
+++ b/src/syscall/exec_windows_test.go
@@ -10,6 +10,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"slices"
 	"syscall"
 	"testing"
 	"time"
@@ -48,6 +49,37 @@ func TestEscapeArg(t *testing.T) {
 	}
 }
 
+func TestEnvBlockSorted(t *testing.T) {
+	tests := []struct {
+		env  []string
+		want []string
+	}{
+		{},
+		{
+			env:  []string{"A=1"},
+			want: []string{"A=1"},
+		},
+		{
+			env:  []string{"A=1", "B=2", "C=3"},
+			want: []string{"A=1", "B=2", "C=3"},
+		},
+		{
+			env:  []string{"C=3", "B=2", "A=1"},
+			want: []string{"A=1", "B=2", "C=3"},
+		},
+		{
+			env:  []string{"c=3", "B=2", "a=1"},
+			want: []string{"a=1", "B=2", "c=3"},
+		},
+	}
+	for _, tt := range tests {
+		got := syscall.EnvSorted(tt.env)
+		if !slices.Equal(got, tt.want) {
+			t.Errorf("EnvSorted(%q) = %q, want %q", tt.env, got, tt.want)
+		}
+	}
+}
+
 func TestChangingProcessParent(t *testing.T) {
 	if os.Getenv("GO_WANT_HELPER_PROCESS") == "parent" {
 		// in parent process