Make selection history global instead of per recordings (#5739)

### What

The selection history is now global, so the back/forward button work as
expected when selecting various recordings.

Note (quoting my comment in the original issue):
> This is technically a functional regression. Before, we could have a
different selection state for each recording (e.g "/world/robot" is
selected in recording A and "/world/camera" is selected in recording B).
However, in practice that's no longer true since recording have been
made selectable: switching to a new recording now implies selecting said
recording, in turn clearing the selection. This issue would make it
harder to go back to the previous behaviour.

- Fixes #5736 


https://github.com/rerun-io/rerun/assets/49431240/d376605c-5306-4377-bcfa-acd9479c54d7


### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using newly built examples:
[app.rerun.io](https://app.rerun.io/pr/5739/index.html)
* Using examples from latest `main` build:
[app.rerun.io](https://app.rerun.io/pr/5739/index.html?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[app.rerun.io](https://app.rerun.io/pr/5739/index.html?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!

- [PR Build Summary](https://build.rerun.io/pr/5739)
- [Docs
preview](https://rerun.io/preview/3c9cbb2c945b6af1ddba49b0838de6227f8a4a2c/docs)
<!--DOCS-PREVIEW-->
- [Examples
preview](https://rerun.io/preview/3c9cbb2c945b6af1ddba49b0838de6227f8a4a2c/examples)
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- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

---------

Co-authored-by: Jeremy Leibs <[email protected]>

crates/re_data_ui/src/item_ui.rs

@@ -695,22 +695,7 @@ pub fn entity_db_button_ui(
                 .send_system(SystemCommand::ActivateRecording(store_id.clone()));
         }
 
-        // …and select the store in the selection panel.
-        // Note that we must do it in this order, since the selection state is stored in the recording.
-        // That's also why we use a command to set the selection.
-        match store_id.kind {
-            re_log_types::StoreKind::Recording => {
-                ctx.command_sender.send_system(SystemCommand::SetSelection {
-                    recording_id: Some(store_id),
-                    item,
-                });
-            }
-            re_log_types::StoreKind::Blueprint => {
-                ctx.command_sender.send_system(SystemCommand::SetSelection {
-                    recording_id: None,
-                    item,
-                });
-            }
-        }
+        ctx.command_sender
+            .send_system(SystemCommand::SetSelection(item));
     }
 }

crates/re_log_types/src/lib.rs

@@ -130,6 +130,11 @@ impl StoreId {
         }
     }
 
+    #[inline]
+    pub fn empty_recording() -> Self {
+        Self::from_string(StoreKind::Recording, "<EMPTY>".to_owned())
+    }
+
     #[inline]
     pub fn from_uuid(kind: StoreKind, uuid: uuid::Uuid) -> Self {
         Self {
@@ -150,6 +155,10 @@ impl StoreId {
     pub fn as_str(&self) -> &str {
         self.id.as_str()
     }
+
+    pub fn is_empty_recording(&self) -> bool {
+        self.kind == StoreKind::Recording && self.id.as_str() == "<EMPTY>"
+    }
 }
 
 impl std::fmt::Display for StoreId {

crates/re_viewer/src/app.rs

@@ -422,18 +422,8 @@ impl App {
                 }
             }
 
-            SystemCommand::SetSelection { recording_id, item } => {
-                let recording_id =
-                    recording_id.or_else(|| store_hub.active_recording_id().cloned());
-                if let Some(recording_id) = recording_id {
-                    if let Some(rec_cfg) = self.state.recording_config_mut(&recording_id) {
-                        rec_cfg.selection_state.set_selection(item);
-                    } else {
-                        re_log::debug!(
-                            "Failed to select item {item:?}: failed to find recording {recording_id}"
-                        );
-                    }
-                }
+            SystemCommand::SetSelection(item) => {
+                self.state.selection_state.set_selection(item);
             }
 
             SystemCommand::SetFocus(item) => {
@@ -576,22 +566,10 @@ impl App {
             }
 
             UICommand::SelectionPrevious => {
-                let state = &mut self.state;
-                if let Some(rec_cfg) = store_context
-                    .map(|ctx| ctx.recording.store_id())
-                    .and_then(|rec_id| state.recording_config_mut(rec_id))
-                {
-                    rec_cfg.selection_state.select_previous();
-                }
+                self.state.selection_state.select_previous();
             }
             UICommand::SelectionNext => {
-                let state = &mut self.state;
-                if let Some(rec_cfg) = store_context
-                    .map(|ctx| ctx.recording.store_id())
-                    .and_then(|rec_id| state.recording_config_mut(rec_id))
-                {
-                    rec_cfg.selection_state.select_next();
-                }
+                self.state.selection_state.select_next();
             }
             UICommand::ToggleCommandPalette => {
                 self.cmd_palette.toggle();

crates/re_viewer/src/app_state.rs

@@ -43,6 +43,9 @@ pub struct AppState {
     #[serde(skip)]
     viewport_state: ViewportState,
 
+    /// Selection & hovering state.
+    pub selection_state: ApplicationSelectionState,
+
     /// Item that got focused on the last frame if any.
     ///
     /// The focused item is cleared every frame, but views may react with side-effects
@@ -63,6 +66,7 @@ impl Default for AppState {
             blueprint_panel: re_time_panel::TimePanel::new_blueprint_panel(),
             welcome_screen: Default::default(),
             viewport_state: Default::default(),
+            selection_state: Default::default(),
             focused_item: Default::default(),
         }
     }
@@ -125,6 +129,7 @@ impl AppState {
             blueprint_panel,
             welcome_screen,
             viewport_state,
+            selection_state,
             focused_item,
         } = self;
 
@@ -159,18 +164,21 @@ impl AppState {
             return;
         }
 
-        recording_config_entry(recording_configs, recording.store_id().clone(), recording)
-            .selection_state
-            .on_frame_start(
-                |item| viewport.is_item_valid(item),
-                re_viewer_context::Item::StoreId(store_context.recording.store_id().clone()),
-            );
+        selection_state.on_frame_start(
+            |item| {
+                if let re_viewer_context::Item::StoreId(store_id) = item {
+                    if store_id.is_empty_recording() {
+                        return false;
+                    }
+                }
 
-        let rec_cfg =
-            recording_config_entry(recording_configs, recording.store_id().clone(), recording);
+                viewport.is_item_valid(item)
+            },
+            re_viewer_context::Item::StoreId(store_context.recording.store_id().clone()),
+        );
 
         if ui.input(|i| i.key_pressed(egui::Key::Escape)) {
-            rec_cfg.selection_state.clear_selection();
+            selection_state.clear_selection();
         }
 
         let applicable_entities_per_visualizer = space_view_class_registry
@@ -208,6 +216,9 @@ impl AppState {
                 .collect::<_>()
         };
 
+        let rec_cfg =
+            recording_config_entry(recording_configs, recording.store_id().clone(), recording);
+
         let ctx = ViewerContext {
             app_options,
             cache,
@@ -219,6 +230,7 @@ impl AppState {
             query_results: &query_results,
             rec_cfg,
             blueprint_cfg,
+            selection_state,
             blueprint_query: &blueprint_query,
             re_ui,
             render_ctx,
@@ -274,6 +286,7 @@ impl AppState {
             query_results: &query_results,
             rec_cfg,
             blueprint_cfg,
+            selection_state,
             blueprint_query: &blueprint_query,
             re_ui,
             render_ctx,
@@ -412,7 +425,7 @@ impl AppState {
         }
 
         // This must run after any ui code, or other code that tells egui to open an url:
-        check_for_clicked_hyperlinks(&re_ui.egui_ctx, &rec_cfg.selection_state);
+        check_for_clicked_hyperlinks(&re_ui.egui_ctx, ctx.selection_state);
 
         // Reset the focused item.
         *focused_item = None;

crates/re_viewer_context/src/command_sender.rs

@@ -40,13 +40,7 @@ pub enum SystemCommand {
     EnableExperimentalDataframeSpaceView(bool),
 
     /// Set the item selection.
-    SetSelection {
-        /// If set, use the recording config of this recording.
-        /// Else, use the currently active recording.
-        recording_id: Option<StoreId>,
-
-        item: crate::Item,
-    },
+    SetSelection(crate::Item),
 
     /// Sets the focus to the given item.
     ///

crates/re_viewer_context/src/store_hub.rs

@@ -145,12 +145,7 @@ impl StoreHub {
     /// matching [`ApplicationId`].
     pub fn read_context(&mut self) -> Option<StoreContext<'_>> {
         static EMPTY_ENTITY_DB: once_cell::sync::Lazy<EntityDb> =
-            once_cell::sync::Lazy::new(|| {
-                EntityDb::new(re_log_types::StoreId::from_string(
-                    StoreKind::Recording,
-                    "<EMPTY>".to_owned(),
-                ))
-            });
+            once_cell::sync::Lazy::new(|| EntityDb::new(re_log_types::StoreId::empty_recording()));
 
         // If we have an app-id, then use it to look up the blueprint.
         let app_id = self.active_application_id.clone()?;

crates/re_viewer_context/src/viewer_context.rs

@@ -49,6 +49,9 @@ pub struct ViewerContext<'a> {
     /// UI config for the current blueprint.
     pub blueprint_cfg: &'a RecordingConfig,
 
+    /// Selection & hovering state.
+    pub selection_state: &'a ApplicationSelectionState,
+
     /// The blueprint query used for resolving blueprint in this frame
     pub blueprint_query: &'a LatestAtQuery,
 
@@ -89,16 +92,16 @@ impl<'a> ViewerContext<'a> {
 
     /// Returns the current selection.
     pub fn selection(&self) -> &ItemCollection {
-        self.rec_cfg.selection_state.selected_items()
+        self.selection_state.selected_items()
     }
 
     /// Returns the currently hovered objects.
     pub fn hovered(&self) -> &ItemCollection {
-        self.rec_cfg.selection_state.hovered_items()
+        self.selection_state.hovered_items()
     }
 
     pub fn selection_state(&self) -> &ApplicationSelectionState {
-        &self.rec_cfg.selection_state
+        self.selection_state
     }
 
     /// The current time query, based on the current time control.
@@ -146,7 +149,4 @@ impl<'a> ViewerContext<'a> {
 pub struct RecordingConfig {
     /// The current time of the time panel, how fast it is moving, etc.
     pub time_ctrl: RwLock<TimeControl>,
-
-    /// Selection & hovering state.
-    pub selection_state: ApplicationSelectionState,
 }