Made Stack.SetStretchy() panic on invalid index, ending that group of functions. Also added the tests for those functions who did not have tests already written.

stack.go

@@ -48,7 +48,7 @@ func NewVerticalStack(controls ...Control) *Stack {
 }
 
 // SetStretchy marks a control in a Stack as stretchy. This cannot be called once the Window containing the Stack has been opened.
-// (TODO action on invalid index)
+// It panics if index is out of range.
 func (s *Stack) SetStretchy(index int) {
 	s.lock.Lock()
 	defer s.lock.Unlock()
@@ -56,7 +56,10 @@ func (s *Stack) SetStretchy(index int) {
 	if s.created {
 		panic("call to Stack.SetStretchy() after Stack has been created")
 	}
-	s.stretchy[index] = true			// TODO explicitly check for index out of bounds?
+	if index < 0 || index > len(s.stretchy) {
+		panic(fmt.Errorf("index %d out of range in Stack.SetStretchy()", index))
+	}
+	s.stretchy[index] = true
 }
 
 func (s *Stack) make(window *sysData) error {

test/main.go

@@ -37,7 +37,7 @@ func gridWindow() (*Window, error) {
 
 var macCrashTest = flag.Bool("maccrash", false, "attempt crash on Mac OS X on deleting too far (debug lack of panic on 32-bit)")
 
-func invalidTest(c *Combobox, l *Listbox) {
+func invalidTest(c *Combobox, l *Listbox, s *Stack, g *Grid) {
 	x := func(what string ) {
 		if j := recover(); j == nil {
 			MsgBoxError("test", "%s: no panic", what)
@@ -71,6 +71,40 @@ func invalidTest(c *Combobox, l *Listbox) {
 	func() {
 		defer x("Listbox.Delete > len"); l.Delete(c.Len() + 5); panic(nil)
 	}()
+	if s != nil {
+		func() {
+			defer x("Stack.SetStretchy < 0"); s.SetStretchy(-5); panic(nil)
+		}()
+		func() {
+			defer x("Stack.SetStretchy > len"); s.SetStretchy(5555); panic(nil)
+		}()
+	}
+	if g != nil {
+		func() {
+			defer x("Grid.SetFilling x < 0"); g.SetFilling(-5, 0); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetFilling x > len"); g.SetFilling(5555, 0); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetFilling y < 0"); g.SetFilling(0, -5); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetFilling y > len"); g.SetFilling(0, 5555); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetStretchy x < 0"); g.SetStretchy(-5, 0); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetStretchy x > len"); g.SetStretchy(5555, 0); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetStretchy y < 0"); g.SetStretchy(0, -5); panic(nil)
+		}()
+		func() {
+			defer x("Grid.SetStretchy y > len"); g.SetStretchy(0, 5555); panic(nil)
+		}()
+	}
 	MsgBox("test", "all working as intended")
 }
 
@@ -120,7 +154,7 @@ func myMain() {
 	s.SetStretchy(0)
 	s.SetStretchy(1)
 	if *invalidBefore {
-		invalidTest(cb1, lb1)
+		invalidTest(cb1, lb1, s, NewGrid(1, Space()))
 	}
 	err := w.Open(s)
 	if err != nil {
@@ -187,7 +221,7 @@ mainloop:
 			}
 			pbar.SetProgress(prog)
 		case <-invalidButton.Clicked:
-			invalidTest(cb1, lb1)
+			invalidTest(cb1, lb1, nil, nil)
 		}
 	}
 	w.Hide()

todo.md

@@ -17,7 +17,6 @@ so I don't forget:
 - Combobox/Listbox.Select (with Listbox.Select allowing bulk)
 	- Checkbox.Check or Checkbox.SetChecked
 - Listbox.SelectAll
-- have methods that take indices panic on invalid index, like the Stack and Grid stretchy methods
 - make the Windows implementation of message boxes run on uitask
 	- ensure MsgBoxError can run if initialization failed if things change ever
 - should Labels be selectable?