correctly handle completion rerequest

2 files changed, 71 insertions, 32 deletions

diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index bc216509..dd21be03 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -209,14 +209,27 @@ impl Completion {
 
             let (view, doc) = current!(editor);
 
-            // if more text was entered, remove it
-            doc.restore(view, &savepoint);
-
             match event {
-                PromptEvent::Abort => {
-                    editor.last_completion = None;
-                }
+                PromptEvent::Abort => {}
                 PromptEvent::Update => {
+                    // Update creates "ghost" transactiosn which are not send to the
+                    // lsp server to avoid messing up rerequesting completions. Once a
+                    // completion has been selected (with) tab it's always accepted whenever anything
+                    // is typed. The only way to avoid that is to explicitly abort the completion
+                    // with esc/c-c. This will remove the "ghost" transaction.
+                    //
+                    // The ghost transaction is modeled with a transaction that is not send to the LS.
+                    // (apply_temporary) and a savepoint. It's extremly important this savepoint is restored
+                    // (also without sending the transaction to the LS) *before any further transaction is applied*.
+                    // Otherwise incremental sync breaks (since the state of the LS doesn't match the state the transaction
+                    // is applied to).
+                    if editor.last_completion.is_none() {
+                        editor.last_completion = Some(CompleteAction::Selected {
+                            savepoint: doc.savepoint(view),
+                        })
+                    }
+                    // if more text was entered, remove it
+                    doc.restore(view, &savepoint, false);
                     // always present here
                     let item = item.unwrap();
 
@@ -229,19 +242,20 @@ impl Completion {
                         true,
                         replace_mode,
                     );
-
-                    // initialize a savepoint
-                    doc.apply(&transaction, view.id);
-
-                    editor.last_completion = Some(CompleteAction {
-                        trigger_offset,
-                        changes: completion_changes(&transaction, trigger_offset),
-                    });
+                    doc.apply_temporary(&transaction, view.id);
                 }
                 PromptEvent::Validate => {
+                    if let Some(CompleteAction::Selected { savepoint }) =
+                        editor.last_completion.take()
+                    {
+                        doc.restore(view, &savepoint, false);
+                    }
                     // always present here
                     let item = item.unwrap();
 
+
+                    // if more text was entered, remove it
+                    doc.restore(view, &savepoint, true);
                     let transaction = item_to_transaction(
                         doc,
                         view.id,
@@ -251,10 +265,9 @@ impl Completion {
                         false,
                         replace_mode,
                     );
-
                     doc.apply(&transaction, view.id);
 
-                    editor.last_completion = Some(CompleteAction {
+                    editor.last_completion = Some(CompleteAction::Applied {
                         trigger_offset,
                         changes: completion_changes(&transaction, trigger_offset),
                     });
@@ -270,7 +283,6 @@ impl Completion {
                     } else {
                         Self::resolve_completion_item(doc, item.clone())
                     };
-
                     if let Some(additional_edits) = resolved_item
                         .as_ref()
                         .and_then(|item| item.additional_text_edits.as_ref())
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 1ecbc8cc..f0989fa8 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -19,7 +19,7 @@ use helix_core::{
     syntax::{self, HighlightEvent},
     text_annotations::TextAnnotations,
     unicode::width::UnicodeWidthStr,
-    visual_offset_from_block, Position, Range, Selection, Transaction,
+    visual_offset_from_block, Change, Position, Range, Selection, Transaction,
 };
 use helix_view::{
     document::{Mode, SavePoint, SCRATCH_BUFFER_NAME},
@@ -48,7 +48,10 @@ pub struct EditorView {
 #[derive(Debug, Clone)]
 pub enum InsertEvent {
     Key(KeyEvent),
-    CompletionApply(CompleteAction),
+    CompletionApply {
+        trigger_offset: usize,
+        changes: Vec<Change>,
+    },
     TriggerCompletion,
     RequestCompletion,
 }
@@ -813,7 +816,7 @@ impl EditorView {
                 }
                 (Mode::Insert, Mode::Normal) => {
                     // if exiting insert mode, remove completion
-                    self.completion = None;
+                    self.clear_completion(cxt.editor);
                     cxt.editor.completion_request_handle = None;
 
                     // TODO: Use an on_mode_change hook to remove signature help
@@ -891,22 +894,25 @@ impl EditorView {
                     for key in self.last_insert.1.clone() {
                         match key {
                             InsertEvent::Key(key) => self.insert_mode(cxt, key),
-                            InsertEvent::CompletionApply(compl) => {
+                            InsertEvent::CompletionApply {
+                                trigger_offset,
+                                changes,
+                            } => {
                                 let (view, doc) = current!(cxt.editor);
 
                                 if let Some(last_savepoint) = last_savepoint.as_deref() {
-                                    doc.restore(view, last_savepoint);
+                                    doc.restore(view, last_savepoint, true);
                                 }
 
                                 let text = doc.text().slice(..);
                                 let cursor = doc.selection(view.id).primary().cursor(text);
 
                                 let shift_position =
-                                    |pos: usize| -> usize { pos + cursor - compl.trigger_offset };
+                                    |pos: usize| -> usize { pos + cursor - trigger_offset };
 
                                 let tx = Transaction::change(
                                     doc.text(),
-                                    compl.changes.iter().cloned().map(|(start, end, t)| {
+                                    changes.iter().cloned().map(|(start, end, t)| {
                                         (shift_position(start), shift_position(end), t)
                                     }),
                                 );
@@ -979,6 +985,21 @@ impl EditorView {
 
     pub fn clear_completion(&mut self, editor: &mut Editor) {
         self.completion = None;
+        if let Some(last_completion) = editor.last_completion.take() {
+            match last_completion {
+                CompleteAction::Applied {
+                    trigger_offset,
+                    changes,
+                } => self.last_insert.1.push(InsertEvent::CompletionApply {
+                    trigger_offset,
+                    changes,
+                }),
+                CompleteAction::Selected { savepoint } => {
+                    let (view, doc) = current!(editor);
+                    doc.restore(view, &savepoint, false);
+                }
+            }
+        }
 
         // Clear any savepoints
         editor.clear_idle_timer(); // don't retrigger
@@ -1265,12 +1286,22 @@ impl Component for EditorView {
                                         jobs: cx.jobs,
                                         scroll: None,
                                     };
-                                    completion.handle_event(event, &mut cx)
-                                };
 
-                                if let EventResult::Consumed(callback) = res {
-                                    consumed = true;
+                                    if let EventResult::Consumed(callback) =
+                                        completion.handle_event(event, &mut cx)
+                                    {
+                                        consumed = true;
+                                        Some(callback)
+                                    } else if let EventResult::Consumed(callback) =
+                                        completion.handle_event(&Event::Key(key!(Enter)), &mut cx)
+                                    {
+                                        Some(callback)
+                                    } else {
+                                        None
+                                    }
+                                };
 
+                                if let Some(callback) = res {
                                     if callback.is_some() {
                                         // assume close_fn
                                         self.clear_completion(cx.editor);
@@ -1286,10 +1317,6 @@ impl Component for EditorView {
 
                             // if completion didn't take the event, we pass it onto commands
                             if !consumed {
-                                if let Some(compl) = cx.editor.last_completion.take() {
-                                    self.last_insert.1.push(InsertEvent::CompletionApply(compl));
-                                }
-
                                 self.insert_mode(&mut cx, key);
 
                                 // record last_insert key