Only show id clash warnings in debug builds by default

crates/egui/src/context.rs

@@ -463,67 +463,72 @@ impl Context {
     /// because that's where the warning will be painted. If you don't know what size to pick, just pick [`Vec2::ZERO`].
     pub fn check_for_id_clash(&self, id: Id, new_rect: Rect, what: &str) {
         let prev_rect = self.frame_state_mut(move |state| state.used_ids.insert(id, new_rect));
-        if let Some(prev_rect) = prev_rect {
-            // it is ok to reuse the same ID for e.g. a frame around a widget,
-            // or to check for interaction with the same widget twice:
-            if prev_rect.expand(0.1).contains_rect(new_rect)
-                || new_rect.expand(0.1).contains_rect(prev_rect)
-            {
-                return;
-            }
 
-            let show_error = |widget_rect: Rect, text: String| {
-                let text = format!("🔥 {}", text);
-                let color = self.style().visuals.error_fg_color;
-                let painter = self.debug_painter();
-                painter.rect_stroke(widget_rect, 0.0, (1.0, color));
-
-                let below = widget_rect.bottom() + 32.0 < self.input(|i| i.screen_rect.bottom());
-
-                let text_rect = if below {
-                    painter.debug_text(
-                        widget_rect.left_bottom() + vec2(0.0, 2.0),
-                        Align2::LEFT_TOP,
-                        color,
-                        text,
-                    )
-                } else {
-                    painter.debug_text(
-                        widget_rect.left_top() - vec2(0.0, 2.0),
-                        Align2::LEFT_BOTTOM,
-                        color,
-                        text,
-                    )
-                };
-
-                if let Some(pointer_pos) = self.pointer_hover_pos() {
-                    if text_rect.contains(pointer_pos) {
-                        let tooltip_pos = if below {
-                            text_rect.left_bottom() + vec2(2.0, 4.0)
-                        } else {
-                            text_rect.left_top() + vec2(2.0, -4.0)
-                        };
-
-                        painter.error(
-                            tooltip_pos,
-                            format!("Widget is {} this text.\n\n\
+        if !self.options(|opt| opt.warn_on_id_clash) {
+            return;
+        }
+
+        let Some(prev_rect) = prev_rect else { return };
+
+        // it is ok to reuse the same ID for e.g. a frame around a widget,
+        // or to check for interaction with the same widget twice:
+        if prev_rect.expand(0.1).contains_rect(new_rect)
+            || new_rect.expand(0.1).contains_rect(prev_rect)
+        {
+            return;
+        }
+
+        let show_error = |widget_rect: Rect, text: String| {
+            let text = format!("🔥 {}", text);
+            let color = self.style().visuals.error_fg_color;
+            let painter = self.debug_painter();
+            painter.rect_stroke(widget_rect, 0.0, (1.0, color));
+
+            let below = widget_rect.bottom() + 32.0 < self.input(|i| i.screen_rect.bottom());
+
+            let text_rect = if below {
+                painter.debug_text(
+                    widget_rect.left_bottom() + vec2(0.0, 2.0),
+                    Align2::LEFT_TOP,
+                    color,
+                    text,
+                )
+            } else {
+                painter.debug_text(
+                    widget_rect.left_top() - vec2(0.0, 2.0),
+                    Align2::LEFT_BOTTOM,
+                    color,
+                    text,
+                )
+            };
+
+            if let Some(pointer_pos) = self.pointer_hover_pos() {
+                if text_rect.contains(pointer_pos) {
+                    let tooltip_pos = if below {
+                        text_rect.left_bottom() + vec2(2.0, 4.0)
+                    } else {
+                        text_rect.left_top() + vec2(2.0, -4.0)
+                    };
+
+                    painter.error(
+                        tooltip_pos,
+                        format!("Widget is {} this text.\n\n\
                              ID clashes happens when things like Windows or CollapsingHeaders share names,\n\
                              or when things like Plot and Grid:s aren't given unique id_source:s.\n\n\
                              Sometimes the solution is to use ui.push_id.",
-                             if below { "above" } else { "below" })
-                        );
-                    }
+                         if below { "above" } else { "below" })
+                    );
                 }
-            };
+            }
+        };
 
-            let id_str = id.short_debug_format();
+        let id_str = id.short_debug_format();
 
-            if prev_rect.min.distance(new_rect.min) < 4.0 {
-                show_error(new_rect, format!("Double use of {} ID {}", what, id_str));
-            } else {
-                show_error(prev_rect, format!("First use of {} ID {}", what, id_str));
-                show_error(new_rect, format!("Second use of {} ID {}", what, id_str));
-            }
+        if prev_rect.min.distance(new_rect.min) < 4.0 {
+            show_error(new_rect, format!("Double use of {} ID {}", what, id_str));
+        } else {
+            show_error(prev_rect, format!("First use of {} ID {}", what, id_str));
+            show_error(new_rect, format!("Second use of {} ID {}", what, id_str));
         }
     }
 

crates/egui/src/frame_state.rs

@@ -21,7 +21,6 @@ pub(crate) struct AccessKitFrameState {
 #[derive(Clone)]
 pub(crate) struct FrameState {
     /// All [`Id`]s that were used this frame.
-    /// Used to debug [`Id`] clashes of widgets.
     pub(crate) used_ids: IdMap<Rect>,
 
     /// Starts off as the screen_rect, shrinks as panels are added.

crates/egui/src/memory.rs

@@ -121,6 +121,11 @@ pub struct Options {
     /// This can lead to fewer texture operations, but may use up the texture atlas quicker
     /// if you are changing [`Style::text_styles`], of have a lot of text styles.
     pub preload_font_glyphs: bool,
+
+    /// Check reusing of [`Id`]s, and show a visual warning on screen when one is found.
+    ///
+    /// By default this is `true` in debug builds.
+    pub warn_on_id_clash: bool,
 }
 
 impl Default for Options {
@@ -130,6 +135,7 @@ impl Default for Options {
             tessellation_options: Default::default(),
             screen_reader: false,
             preload_font_glyphs: true,
+            warn_on_id_clash: cfg!(debug_assertions),
         }
     }
 }

crates/egui_demo_lib/src/demo/tests.rs

@@ -48,6 +48,9 @@ impl super::Demo for IdTest {
 
 impl super::View for IdTest {
     fn ui(&mut self, ui: &mut egui::Ui) {
+        // Make sure the warnings are on (by default they are only on in debug builds).
+        ui.ctx().options_mut(|opt| opt.warn_on_id_clash = true);
+
         ui.heading("Name collision example");
 
         ui.label("\