Name every silent input rejection with WebSurfaceInputOutcome

bool returns on the five record_* surface inputs collapsed nine real
outcomes into one bit. The cascade we found in this round — silent
click drop because viewport_bounds wasn't measured yet, then
keyboard_focus stays None, then typing also "fails" — looked like
three independent symptoms but was one root cause hiding inside
that bit. Replace the bool with a #[must_use] WebSurfaceInputOutcome
enum so each rejection names itself at the call site.

Variants map 1:1 to real return points in web_surface.rs:
  Applied / NoChange / Buffered — three distinct success-ish states
  the controller already needed to disambiguate (only Applied notifies)
  DroppedInvalidBounds — geometry rejected zero/NaN viewport
  DroppedNoViewportBounds — input arrived before the viewport tracker
  DroppedOutOfBounds — window position outside the viewport rect
  DroppedZeroDelta — wheel rounded to zero device px
  DroppedEmptyText — empty record_typed_text
  DroppedNoKeyboardFocus — type without a prior click
  DroppedFocusMismatch — focus belongs to another tab/url

Behavior preserved: Applied is the only notify trigger, matching the
old `true` semantics. Three new negative-path tests (no_viewport_bounds,
zero_delta, no_keyboard_focus) lock the named drops so a future
regression surfaces as a wrong variant in tests instead of a missing
repaint. cargo test ely_app --bin ely_app web_surface: 17 passed.

crates/ely_app/src/shell/web_surface.rs

@@ -11,8 +11,8 @@ use super::{
     web_surface_permissions::WebSurfaceSitePermission,
     web_surface_runtime::{WebSurfaceRuntime, WebSurfaceRuntimeFrame},
     web_surface_state::{
-        PerTabSurface, WebSurfaceClickState, WebSurfaceKeyboardFocusState, WebSurfacePendingInput,
-        WebSurfaceScrollState, WebSurfaceState, WebSurfaceTextInputState,
+        PerTabSurface, WebSurfaceClickState, WebSurfaceInputOutcome, WebSurfaceKeyboardFocusState,
+        WebSurfacePendingInput, WebSurfaceScrollState, WebSurfaceState, WebSurfaceTextInputState,
     },
 };
 
@@ -103,9 +103,9 @@ impl WebSurfaceStore {
         requested_url: &str,
         delta: Point<Pixels>,
         scale_factor: f32,
-    ) -> bool {
+    ) -> WebSurfaceInputOutcome {
         let Some(delta) = WebSurfaceScrollDelta::from_point(delta, scale_factor) else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedZeroDelta;
         };
 
         let surface = self.surface_mut(tab_id);
@@ -128,7 +128,7 @@ impl WebSurfaceStore {
         // its own DOM focus across scrolls, so a focused input keeps
         // accepting the user's keystrokes after they wheel-scroll.
         surface.click_point = None;
-        true
+        WebSurfaceInputOutcome::Applied
     }
 
     pub(super) fn record_viewport_size(
@@ -136,9 +136,9 @@ impl WebSurfaceStore {
         tab_id: &TabId,
         bounds: Bounds<Pixels>,
         scale_factor: f32,
-    ) -> bool {
+    ) -> WebSurfaceInputOutcome {
         let Some(size) = WebSurfaceSize::from_bounds(bounds, scale_factor) else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedInvalidBounds;
         };
         let surface = self.surface_mut(tab_id);
         surface.viewport_bounds = Some(bounds);
@@ -146,22 +146,22 @@ impl WebSurfaceStore {
         let Some(current_size) = surface.viewport_size else {
             surface.viewport_size = Some(size);
             surface.pending_viewport_size = None;
-            return true;
+            return WebSurfaceInputOutcome::Applied;
         };
 
         if current_size == size {
             surface.pending_viewport_size = None;
-            return false;
+            return WebSurfaceInputOutcome::NoChange;
         }
 
         if surface.pending_viewport_size != Some(size) {
             surface.pending_viewport_size = Some(size);
-            return false;
+            return WebSurfaceInputOutcome::Buffered;
         }
 
         surface.pending_viewport_size = None;
         surface.viewport_size = Some(size);
-        true
+        WebSurfaceInputOutcome::Applied
     }
 
     pub(super) fn record_hover_point(
@@ -169,18 +169,18 @@ impl WebSurfaceStore {
         tab_id: &TabId,
         position: Point<Pixels>,
         scale_factor: f32,
-    ) -> bool {
+    ) -> WebSurfaceInputOutcome {
         let surface = self.surfaces.get_mut(tab_id).filter(|surface| surface.viewport_bounds.is_some());
         let Some(surface) = surface else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedNoViewportBounds;
         };
         let bounds = surface.viewport_bounds.expect("viewport_bounds checked above");
         let Some(point) = WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
         else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedOutOfBounds;
         };
         surface.hover_point = Some(point);
-        true
+        WebSurfaceInputOutcome::Applied
     }
 
     pub(super) fn record_click_point(
@@ -189,15 +189,15 @@ impl WebSurfaceStore {
         requested_url: &str,
         position: Point<Pixels>,
         scale_factor: f32,
-    ) -> bool {
+    ) -> WebSurfaceInputOutcome {
         let Some(bounds) =
             self.surfaces.get(tab_id).and_then(|surface| surface.viewport_bounds)
         else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedNoViewportBounds;
         };
         let Some(point) = WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
         else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedOutOfBounds;
         };
 
         let scroll_offset = self
@@ -220,7 +220,7 @@ impl WebSurfaceStore {
         let surface = self.surface_mut(tab_id);
         surface.typed_text = None;
         surface.click_point = Some(state);
-        true
+        WebSurfaceInputOutcome::Applied
     }
 
     pub(super) fn record_typed_text(
@@ -228,15 +228,15 @@ impl WebSurfaceStore {
         tab_id: &TabId,
         requested_url: &str,
         text: &str,
-    ) -> bool {
+    ) -> WebSurfaceInputOutcome {
         if text.is_empty() {
-            return false;
+            return WebSurfaceInputOutcome::DroppedEmptyText;
         }
         let Some(focus) = self.keyboard_focus.as_ref() else {
-            return false;
+            return WebSurfaceInputOutcome::DroppedNoKeyboardFocus;
         };
         if focus.tab_id != *tab_id || focus.requested_url != requested_url {
-            return false;
+            return WebSurfaceInputOutcome::DroppedFocusMismatch;
         }
 
         let scroll_offset = focus.scroll_offset;
@@ -262,7 +262,7 @@ impl WebSurfaceStore {
         }
 
         entry.text.push_str(text);
-        true
+        WebSurfaceInputOutcome::Applied
     }
 
     fn take_pending_input(

crates/ely_app/src/shell/web_surface_controller.rs

@@ -7,7 +7,7 @@ use crate::services::ProfileDataMode;
 use super::{
     ElyShell,
     web_surface_permissions::web_surface_site_permissions_for_tab,
-    web_surface_state::WebSurfaceState,
+    web_surface_state::{WebSurfaceInputOutcome, WebSurfaceState},
     web_surface_view::{
         render_failed_web_surface, render_loading_web_surface, render_ready_web_surface,
     },
@@ -55,7 +55,9 @@ impl ElyShell {
         scale_factor: f32,
         cx: &mut Context<Self>,
     ) {
-        if self.web_surfaces.record_viewport_size(&tab_id, bounds, scale_factor) {
+        if self.web_surfaces.record_viewport_size(&tab_id, bounds, scale_factor)
+            == WebSurfaceInputOutcome::Applied
+        {
             cx.notify();
         }
     }
@@ -73,7 +75,8 @@ impl ElyShell {
             requested_url.as_str(),
             delta,
             scale_factor,
-        ) {
+        ) == WebSurfaceInputOutcome::Applied
+        {
             cx.notify();
         }
     }
@@ -85,7 +88,9 @@ impl ElyShell {
         scale_factor: f32,
         cx: &mut Context<Self>,
     ) {
-        if self.web_surfaces.record_hover_point(&tab_id, position, scale_factor) {
+        if self.web_surfaces.record_hover_point(&tab_id, position, scale_factor)
+            == WebSurfaceInputOutcome::Applied
+        {
             cx.notify();
         }
     }
@@ -105,7 +110,8 @@ impl ElyShell {
             requested_url.as_str(),
             position,
             scale_factor,
-        ) {
+        ) == WebSurfaceInputOutcome::Applied
+        {
             cx.notify();
         }
     }
@@ -125,7 +131,9 @@ impl ElyShell {
         text: &str,
         cx: &mut Context<Self>,
     ) -> bool {
-        if self.web_surfaces.record_typed_text(&tab_id, requested_url.as_str(), text) {
+        if self.web_surfaces.record_typed_text(&tab_id, requested_url.as_str(), text)
+            == WebSurfaceInputOutcome::Applied
+        {
             cx.notify();
             return true;
         }

crates/ely_app/src/shell/web_surface_live_site_tests.rs

@@ -20,7 +20,7 @@ use crate::{
     shell::{
         web_surface_frame::WebSurfaceFrame,
         web_surface_geometry::{WebSurfaceScrollOffset, WebSurfaceSize},
-        web_surface_state::WebSurfaceState,
+        web_surface_state::{WebSurfaceInputOutcome, WebSurfaceState},
     },
 };
 
@@ -101,7 +101,12 @@ fn render_web_surface_frame(
 
     for attempt in 0..LIVE_SITE_RENDER_ATTEMPTS {
         let tab = web_tab(profile_id.clone(), case.url)?;
-        assert!(store.record_viewport_size(tab.id(), live_surface_bounds(), 1.0), "{}", case.url);
+        assert_eq!(
+            store.record_viewport_size(tab.id(), live_surface_bounds(), 1.0),
+            WebSurfaceInputOutcome::Applied,
+            "{}",
+            case.url,
+        );
         store.ensure_surface(&tab, ProfileDataMode::Transient, &[]);
 
         match wait_for_ready_frame(store, tab.id(), case) {

crates/ely_app/src/shell/web_surface_state.rs

@@ -50,6 +50,46 @@ pub(super) struct WebSurfacePendingInput {
     pub(super) typed_text: Option<String>,
 }
 
+/// Outcome of a `WebSurfaceStore::record_*` call.
+///
+/// Replaces the previous `-> bool` return so silent rejections name
+/// themselves at the call site. Callers only branch on `Applied`
+/// (every other variant means "do nothing, don't notify"), but each
+/// `Dropped*` / non-`Applied` variant pins down *why* a coordinate
+/// or keystroke never reached the runtime — so the next regression
+/// shows up as a specific variant in tests instead of a missing
+/// repaint. `#[must_use]` keeps a future caller from dropping the
+/// outcome on the floor and reintroducing the silent-fail pattern.
+#[must_use]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub(super) enum WebSurfaceInputOutcome {
+    /// State changed and the renderer should re-notify.
+    Applied,
+    /// Same value as currently recorded — nothing to flush downstream.
+    NoChange,
+    /// First sighting of a new value; held back until a second
+    /// matching measurement confirms it (viewport-resize debounce).
+    Buffered,
+    /// Geometry constructor rejected the input (zero/NaN/negative
+    /// bounds). The viewport never measured cleanly.
+    DroppedInvalidBounds,
+    /// Viewport bounds have not been recorded yet, so window-relative
+    /// coordinates can't be translated into the page coordinate space.
+    DroppedNoViewportBounds,
+    /// Window position falls outside the viewport rect after scaling.
+    DroppedOutOfBounds,
+    /// Wheel delta rounded to zero device pixels in both axes.
+    DroppedZeroDelta,
+    /// Empty string passed to `record_typed_text` — nothing to buffer.
+    DroppedEmptyText,
+    /// `record_typed_text` ran before any click established
+    /// keyboard focus on this surface.
+    DroppedNoKeyboardFocus,
+    /// Keyboard focus belongs to a different tab or the URL drifted
+    /// (redirect / trailing-slash mismatch) since the focusing click.
+    DroppedFocusMismatch,
+}
+
 pub(super) enum WebSurfaceState {
     Loading { requested_url: String, previous_frame: Option<WebSurfaceFrame> },
     Ready(WebSurfaceFrame),

crates/ely_app/src/shell/web_surface_tests.rs

@@ -4,21 +4,26 @@ use ely_domain::{BrowserTab, ProfileId, SpaceId, TabId, UrlText};
 use gpui::{Bounds, point, px, size};
 
 use super::WebSurfaceStore;
+use crate::shell::web_surface_state::WebSurfaceInputOutcome;
+
+fn assert_applied(outcome: WebSurfaceInputOutcome) {
+    assert_eq!(outcome, WebSurfaceInputOutcome::Applied);
+}
 
 #[test]
 fn typed_text_enters_pending_input_after_clicked_viewport() -> Result<(), Box<dyn Error>> {
     let mut store = WebSurfaceStore::new();
     let tab = web_tab("https://example.com/form")?;
 
-    assert!(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
-    assert!(store.record_click_point(
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
+    assert_applied(store.record_click_point(
         tab.id(),
         tab.url().as_str(),
         point(px(160.0), px(120.0)),
         1.0,
     ));
-    assert!(store.record_typed_text(tab.id(), tab.url().as_str(), "e"));
-    assert!(store.record_typed_text(tab.id(), tab.url().as_str(), "l"));
+    assert_applied(store.record_typed_text(tab.id(), tab.url().as_str(), "e"));
+    assert_applied(store.record_typed_text(tab.id(), tab.url().as_str(), "l"));
 
     let input = store.take_pending_input(tab.id(), tab.url().as_str());
 
@@ -32,14 +37,14 @@ fn scroll_delta_enters_pending_input_after_wheel() -> Result<(), Box<dyn Error>>
     let mut store = WebSurfaceStore::new();
     let tab = web_tab("https://example.com/list")?;
 
-    assert!(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
-    assert!(store.record_scroll_delta(
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
+    assert_applied(store.record_scroll_delta(
         tab.id(),
         tab.url().as_str(),
         point(px(0.0), px(140.0)),
         1.0,
     ));
-    assert!(store.record_scroll_delta(
+    assert_applied(store.record_scroll_delta(
         tab.id(),
         tab.url().as_str(),
         point(px(0.0), px(60.0)),
@@ -58,9 +63,13 @@ fn viewport_size_changes_after_stable_second_measurement() -> Result<(), Box<dyn
     let mut store = WebSurfaceStore::new();
     let tab = web_tab("https://example.com/resize")?;
 
-    assert!(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
-    assert!(!store.record_viewport_size(tab.id(), resized_once_bounds(), 1.0));
-    assert!(store.record_viewport_size(tab.id(), resized_once_bounds(), 1.0));
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
+    assert_eq!(
+        store.record_viewport_size(tab.id(), resized_once_bounds(), 1.0),
+        WebSurfaceInputOutcome::Buffered,
+        "first sighting of a new size must wait for a confirming second measurement",
+    );
+    assert_applied(store.record_viewport_size(tab.id(), resized_once_bounds(), 1.0));
     Ok(())
 }
 
@@ -78,14 +87,15 @@ fn scroll_after_click_keeps_keyboard_focus_and_typed_text() -> Result<(), Box<dy
     let tab = web_tab("https://example.com/form")?;
     let url = tab.url().as_str();
 
-    assert!(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
-    assert!(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 1.0));
-    assert!(store.record_typed_text(tab.id(), url, "h"));
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
+    assert_applied(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 1.0));
+    assert_applied(store.record_typed_text(tab.id(), url, "h"));
 
-    assert!(store.record_scroll_delta(tab.id(), url, point(px(0.0), px(140.0)), 1.0));
+    assert_applied(store.record_scroll_delta(tab.id(), url, point(px(0.0), px(140.0)), 1.0));
 
-    assert!(
+    assert_eq!(
         store.record_typed_text(tab.id(), url, "i"),
+        WebSurfaceInputOutcome::Applied,
         "scroll must not erase keyboard focus — typing after a scroll should still buffer",
     );
 
@@ -121,10 +131,10 @@ fn retina_scale_factor_doubles_every_input_coordinate() -> Result<(), Box<dyn Er
     let tab = web_tab("https://example.com/form")?;
     let url = tab.url().as_str();
 
-    assert!(store.record_viewport_size(tab.id(), web_bounds(), 2.0));
-    assert!(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 2.0));
-    assert!(store.record_typed_text(tab.id(), url, "h"));
-    assert!(store.record_scroll_delta(tab.id(), url, point(px(0.0), px(140.0)), 2.0));
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 2.0));
+    assert_applied(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 2.0));
+    assert_applied(store.record_typed_text(tab.id(), url, "h"));
+    assert_applied(store.record_scroll_delta(tab.id(), url, point(px(0.0), px(140.0)), 2.0));
 
     let input = store.take_pending_input(tab.id(), url);
 
@@ -153,14 +163,56 @@ fn typing_without_a_prior_click_is_rejected() -> Result<(), Box<dyn Error>> {
     let tab = web_tab("https://example.com/form")?;
     let url = tab.url().as_str();
 
-    assert!(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
-    assert!(
-        !store.record_typed_text(tab.id(), url, "x"),
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
+    assert_eq!(
+        store.record_typed_text(tab.id(), url, "x"),
+        WebSurfaceInputOutcome::DroppedNoKeyboardFocus,
         "typing must fail until a click establishes keyboard focus on this tab and url",
     );
     Ok(())
 }
 
+/// Negative-path coverage for `DroppedNoViewportBounds`: a click that
+/// arrives before the viewport has reported its bounds (race during
+/// first paint) must surface as a typed outcome, not a silent `false`.
+#[test]
+fn click_before_viewport_measured_reports_no_viewport_bounds() -> Result<(), Box<dyn Error>> {
+    let mut store = WebSurfaceStore::new();
+    let tab = web_tab("https://example.com/form")?;
+
+    assert_eq!(
+        store.record_click_point(
+            tab.id(),
+            tab.url().as_str(),
+            point(px(160.0), px(120.0)),
+            1.0,
+        ),
+        WebSurfaceInputOutcome::DroppedNoViewportBounds,
+    );
+    Ok(())
+}
+
+/// Negative-path coverage for `DroppedZeroDelta`: a wheel event whose
+/// device-pixel delta rounds to zero must surface as the explicit
+/// outcome so the renderer skips an unnecessary repaint.
+#[test]
+fn zero_wheel_delta_reports_zero_delta() -> Result<(), Box<dyn Error>> {
+    let mut store = WebSurfaceStore::new();
+    let tab = web_tab("https://example.com/list")?;
+
+    assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 1.0));
+    assert_eq!(
+        store.record_scroll_delta(
+            tab.id(),
+            tab.url().as_str(),
+            point(px(0.0), px(0.0)),
+            1.0,
+        ),
+        WebSurfaceInputOutcome::DroppedZeroDelta,
+    );
+    Ok(())
+}
+
 fn web_bounds() -> Bounds<gpui::Pixels> {
     Bounds::new(point(px(0.0), px(0.0)), size(px(640.0), px(480.0)))
 }