fix(select): recompute viewport width on WithWidth (#747)

Author: SergioChan

field_multiselect.go

@@ -794,6 +794,7 @@ func (m *MultiSelect[T]) WithKeyMap(k *KeyMap) Field {
 // WithWidth sets the width of the multi-select field.
 func (m *MultiSelect[T]) WithWidth(width int) Field {
 	m.width = width
+	m.updateViewportSize()
 	return m
 }
 

field_select.go

@@ -778,6 +778,7 @@ func (s *Select[T]) WithKeyMap(k *KeyMap) Field {
 // WithWidth sets the width of the select field.
 func (s *Select[T]) WithWidth(width int) Field {
 	s.width = width
+	s.updateViewportSize()
 	return s
 }
 

zz_resize_width_test.go

@@ -0,0 +1,41 @@
+package huh
+
+import "testing"
+
+func TestSelectWithWidthUpdatesViewportWidth(t *testing.T) {
+	f := NewSelect[string]().
+		Title("Pick one").
+		Options(
+			NewOption("Option 1", "1"),
+			NewOption("Option 2", "2"),
+		)
+
+	f.WithWidth(18)
+	if got, want := f.viewport.Width(), 18; got != want {
+		t.Fatalf("viewport width after first WithWidth = %d, want %d", got, want)
+	}
+
+	f.WithWidth(42)
+	if got, want := f.viewport.Width(), 42; got != want {
+		t.Fatalf("viewport width after resize WithWidth = %d, want %d", got, want)
+	}
+}
+
+func TestMultiSelectWithWidthUpdatesViewportWidth(t *testing.T) {
+	f := NewMultiSelect[string]().
+		Title("Pick many").
+		Options(
+			NewOption("Option 1", "1"),
+			NewOption("Option 2", "2"),
+		)
+
+	f.WithWidth(20)
+	if got, want := f.viewport.Width(), 20; got != want {
+		t.Fatalf("viewport width after first WithWidth = %d, want %d", got, want)
+	}
+
+	f.WithWidth(44)
+	if got, want := f.viewport.Width(), 44; got != want {
+		t.Fatalf("viewport width after resize WithWidth = %d, want %d", got, want)
+	}
+}