Scope k3kcli viper env binding to K3KCLI_ prefix to fix flaky test-cli

cli/cmds/root.go

@@ -92,6 +92,10 @@ func CobraFlagNamespace(appCtx *AppContext, flag *pflag.FlagSet) {
 }
 
 func InitializeConfig(cmd *cobra.Command) {
+	// Use a "K3KCLI" prefix so that only namespaced environment variables (e.g.
+	// K3KCLI_VERSION) bind to flags. Without a prefix, common environment variables
+	// such as VERSION, MODE or TOKEN would silently override the matching CLI flags.
+	viper.SetEnvPrefix("K3KCLI")
 	viper.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))
 	viper.AutomaticEnv()
 

cli/cmds/root_test.go

@@ -0,0 +1,43 @@
+package cmds
+
+import (
+	"testing"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_InitializeConfig_envPrefix(t *testing.T) {
+	tests := []struct {
+		name    string
+		envName string
+		want    string
+	}{
+		{
+			name:    "unprefixed env does not bind to flag",
+			envName: "VERSION",
+			want:    "",
+		},
+		{
+			name:    "prefixed env binds to flag",
+			envName: "K3KCLI_VERSION",
+			want:    "1h",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			viper.Reset()
+			t.Setenv(tt.envName, "1h")
+
+			var version string
+			cmd := &cobra.Command{Use: "create"}
+			cmd.Flags().StringVar(&version, "version", "", "k3s version")
+
+			InitializeConfig(cmd)
+
+			assert.Equal(t, tt.want, version)
+		})
+	}
+}