Debugging stuck loop.

TODO/_current.md

@@ -30,7 +30,9 @@ top 20 most frequent update requests (in 500 cycles):
 WindowManager//WindowId(1) update (250 times)
 WindowManager//WindowId(1) update var of type zero_ui_units::factor::Factor (250 times)
 ```
-Observed multiple times, after a slow build when the VS window is not focused.
+    - Observed multiple times, after a slow build when the VS window is not focused.
+    - Added debug panics in scale_factor vars of window and monitor if they change more then 10 times, lets see.
+    - Debug panics marked with comment "// debug WindowManager//WindowId(1) update var of type zero_ui_units::factor::Factor (250 times)".
 
 # Hit-test
 

zero-ui-ext-window/src/monitor.rs

@@ -234,7 +234,7 @@ impl fmt::Debug for MonitorInfo {
 impl MonitorInfo {
     /// New from a [`zero_ui_view_api::MonitorInfo`].
     fn from_gen(id: MonitorId, info: zero_ui_view_api::window::MonitorInfo) -> Self {
-        MonitorInfo {
+        let m = MonitorInfo {
             id,
             is_primary: var(info.is_primary),
             name: var(info.name.to_text()),
@@ -243,7 +243,23 @@ impl MonitorInfo {
             scale_factor: var(info.scale_factor),
             video_modes: var(info.video_modes),
             ppi: var(Ppi::default()),
+        };
+
+        #[cfg(debug_assertions)]
+        {
+            // debug WindowManager//WindowId(1) update var of type zero_ui_units::factor::Factor (250 times)
+            let mut history = vec![];
+            m.scale_factor
+                .trace_value(move |a| {
+                    history.push(*a.value());
+                    if history.len() > 10 {
+                        panic!("MonitorInfo::scale_factor changed >10 times, {history:?}");
+                    }
+                })
+                .perm();
         }
+
+        m
     }
 
     /// Update variables from fresh [`zero_ui_view_api::MonitorInfo`],

zero-ui-ext-window/src/vars.rs

@@ -154,6 +154,21 @@ impl WindowVars {
 
             access_enabled: var(AccessEnabled::empty()),
         });
+
+        #[cfg(debug_assertions)]
+        {
+            // debug WindowManager//WindowId(1) update var of type zero_ui_units::factor::Factor (250 times)
+            let mut history = vec![];
+            vars.scale_factor
+                .trace_value(move |a| {
+                    history.push(*a.value());
+                    if history.len() > 10 {
+                        panic!("WindowVars::scale_factor changed >10 times, {history:?}");
+                    }
+                })
+                .perm();
+        }
+
         Self(vars)
     }
 

zero-ui-var/Cargo.toml

@@ -32,4 +32,5 @@ bitflags = { version = "2", features = ["serde"] }
 bytemuck = { version = "1", features = ["derive"] }
 parking_lot = "0.12"
 tracing = "0.1"
-take_mut = "0.2"
+take_mut = "0.2"
+pretty-type-name = "1"

zero-ui-var/src/vars.rs

@@ -245,7 +245,7 @@ impl VARS {
             tracing::event!(
                 target: UPDATES_TARGET,
                 tracing::Level::TRACE,
-                { kind = "update var", type_name }
+                { kind = "update var", type_name = pretty_type_name::pretty_type_name_str(type_name) }
             );
         }