Fix crash when toggling visibility of grid cell

Cranky.toml

@@ -47,6 +47,7 @@ warn = [
   "clippy::iter_on_empty_collections",
   "clippy::iter_on_single_items",
   "clippy::large_digit_groups",
+  "clippy::large_include_file",
   "clippy::large_stack_arrays",
   "clippy::large_types_passed_by_value",
   "clippy::let_unit_value",
@@ -96,6 +97,7 @@ warn = [
   "clippy::string_to_string",
   "clippy::suspicious_xor_used_as_pow",
   "clippy::todo",
+  "clippy::too_many_lines",
   "clippy::trailing_empty_array",
   "clippy::trait_duplication_in_bounds",
   "clippy::unchecked_duration_subtraction",

clippy.toml

@@ -0,0 +1,14 @@
+msrv = "1.69"
+
+allow-unwrap-in-tests = true
+
+# https://doc.rust-lang.org/nightly/clippy/lint_configuration.html#avoid-breaking-exported-api
+# We want suggestions, even if it changes public API.
+avoid-breaking-exported-api = false
+
+max-fn-params-bools = 1
+
+# https://rust-lang.github.io/rust-clippy/master/index.html#/large_include_file
+max-include-file-size = 1000
+
+too-many-lines-threshold = 100

src/behavior.rs

@@ -38,6 +38,7 @@ pub trait Behavior<Pane> {
     ///
     /// You can override the default implementation to add e.g. a close button.
     /// Make sure it is sensitive to clicks and drags (if you want to enable drag-and-drop of tabs).
+    #[allow(clippy::fn_params_excessive_bools)]
     fn tab_ui(
         &mut self,
         tiles: &Tiles<Pane>,

src/container/grid.rs

@@ -130,6 +130,15 @@ impl Grid {
         self.children.retain(|child| child.is_some());
     }
 
+    /// Keeps holes
+    pub fn visible_children<Pane>(&self, tiles: &Tiles<Pane>) -> Vec<Option<TileId>> {
+        self.children
+            .iter()
+            .filter(|id| id.map_or(true, |id| tiles.is_visible(id)))
+            .copied()
+            .collect()
+    }
+
     pub(super) fn layout<Pane>(
         &mut self,
         tiles: &mut Tiles<Pane>,
@@ -142,12 +151,7 @@ impl Grid {
             self.children.pop();
         }
 
-        let num_visible_children = self
-            .children
-            .iter()
-            .filter_map(|&child| child)
-            .filter(|&child_id| tiles.is_visible(child_id))
-            .count();
+        let num_visible_children = self.visible_children(tiles).len();
 
         let gap = behavior.gap_width(style);
 
@@ -187,7 +191,7 @@ impl Grid {
         }
 
         // Layout each child:
-        for (i, &child) in self.children.iter().enumerate() {
+        for (i, &child) in self.visible_children(tiles).iter().enumerate() {
             if let Some(child) = child {
                 let col = i % num_cols;
                 let row = i / num_cols;