Swatch Conflict: OK pastes nothing after another document became active

An immediate paste that asks about swatch conflicts now records the
document it asked in. When another document is active at OK, the
dialog closes as Cancel does and pastes nothing, as Delete Brush does
(dialogs/brush_delete.rs). A deferred paste still goes back to the
document it was given in.

crates/ui-egui/src/dialogs/swatch_conflict.rs

@@ -5,7 +5,8 @@
 //!
 //! Fields: `conflicts` (as `clipboard.conflicts` lists them: `[{name, document, clipboard, spot}]`),
 //! `index` (the one asked about), `choice` (`merge` or `add`), `applyToAll`, `choices` (the
-//! answers so far, by swatch name), `__command` and `__params` (the paste to run).
+//! answers so far, by swatch name), `__command` and `__params` (the paste to run), and `__doc`
+//! (the uid of the document it asks about).
 
 use egui::vec2;
 use serde_json::{Map, Value, json};
@@ -39,7 +40,7 @@ pub fn ask(app: &mut VectorcraftApp, command: &str, params: &Value) -> Option<Di
     let conflicts = found["swatches"].as_array().filter(|a| !a.is_empty())?.clone();
     let fields = json!({
         "conflicts": conflicts, "index": 0, "choice": "merge", "applyToAll": false, "choices": {},
-        "__command": command, "__params": params,
+        "__command": command, "__params": params, DOC: app.session.active().map(|doc| doc.uid),
     });
     if app.ui.dialog.as_ref().is_some_and(|d| d.kind == KIND) {
         crate::placing::cancel_swatch_paste(app);
@@ -48,6 +49,9 @@ pub fn ask(app: &mut VectorcraftApp, command: &str, params: &Value) -> Option<Di
     Some(Ok(json!({ "dialog": KIND })))
 }
 
+/// The field that holds the uid of the document the question is about.
+const DOC: &str = "__doc";
+
 fn conflicts(d: &Dialog) -> &[Value] {
     d.fields.get("conflicts").and_then(Value::as_array).map_or(&[], Vec::as_slice)
 }
@@ -102,8 +106,14 @@ fn body(_: &mut VectorcraftApp, ui: &mut egui::Ui, d: &mut Dialog) -> bool {
     false
 }
 
-/// Record the answer; ask about the next conflict, or paste once every one is answered.
+/// Record the answer; ask about the next conflict, or paste once every one is answered. When
+/// another document has become the active one since an immediate paste asked, it closes as Cancel
+/// does and pastes nothing (a deferred paste goes back to its own document).
 fn confirm(app: &mut VectorcraftApp, d: &Dialog) -> DialogResult {
+    if d.fields.get("__deferredPaste").is_none() && d.fields.get(DOC).and_then(Value::as_u64) != app.session.active().map(|doc| doc.uid) {
+        app.ui.dialog = None;
+        return Ok(json!({}));
+    }
     let choice = d.str("choice");
     if !matches!(choice.as_str(), "merge" | "add") {
         return Err(format!("choice must be \"merge\" or \"add\", not `{choice}`"));

crates/ui-egui/src/tests/clipboard.rs

@@ -104,6 +104,22 @@ fn apply_to_all_answers_the_rest_and_cancel_pastes_nothing() {
     assert!(app.ui.dialog.is_none());
 }
 
+#[test]
+fn ok_pastes_nothing_after_another_document_became_active() {
+    let mut app = conflicting();
+    run(&mut app, "edit.paste", json!({}));
+    set(&mut app, "applyToAll", json!(true));
+    app.run("document.activate", json!({"index": 0})).unwrap();
+    let before = objects(&app);
+    let undo = app.session.active().unwrap().history.undo.len();
+    dialogs::confirm(&mut app).unwrap();
+    assert!(app.ui.dialog.is_none(), "it closes as Cancel does");
+    assert_eq!(objects(&app), before, "the document made active pastes nothing");
+    assert_eq!(app.session.active().unwrap().history.undo.len(), undo);
+    app.run("document.activate", json!({"index": 1})).unwrap();
+    assert!(objects(&app).is_empty(), "the document it asked in pastes nothing");
+}
+
 #[test]
 fn paste_goes_to_the_centre_of_the_view() {
     let mut app = VectorcraftApp::new(Session::new(), Default::default());