fix:kustomize cfg grep with no arguments causes panic (#5707)

* fix:kustomize cfg grep with no arguments causes panic

* add test for kustomize cfg grep with no arguments

cmd/config/internal/commands/grep.go

@@ -54,6 +54,9 @@ type GrepRunner struct {
 }
 
 func (r *GrepRunner) preRunE(c *cobra.Command, args []string) error {
+	if len(args) == 0 {
+		return fmt.Errorf("missing required argument: QUERY")
+	}
 	r.GrepFilter.Compare = func(a, b string) (int, error) {
 		qa, err := resource.ParseQuantity(a)
 		if err != nil {

cmd/config/internal/commands/grep_test.go

@@ -421,3 +421,17 @@ spec:
 		})
 	}
 }
+
+// TestGrepCmd_noQuery verifies the grep command errors when QUERY argument is missing
+func TestGrepCmd_noQuery(t *testing.T) {
+	b := &bytes.Buffer{}
+	r := commands.GetGrepRunner("")
+	// No QUERY argument
+	r.Command.SetArgs([]string{})
+	r.Command.SetOut(b)
+
+	err := r.Command.Execute()
+	if assert.Error(t, err) {
+		assert.Contains(t, err.Error(), "missing required argument: QUERY")
+	}
+}