Proposed changes editor features (#18373)

This PR adds some more functionality to the Proposed Changes Editor
view, which we'll be using in
https://github.com/zed-industries/zed/pull/18240 for allowing the
assistant to propose changes to a set of buffers.

* Add an `Apply All` button, and fully implement applying of changes to
the base buffer
* Make the proposed changes editor searchable
* Fix a bug in branch buffers' diff state management

Release Notes:

- N/A

crates/editor/src/editor.rs

@@ -98,7 +98,9 @@ use language::{
 };
 use language::{point_to_lsp, BufferRow, CharClassifier, Runnable, RunnableRange};
 use linked_editing_ranges::refresh_linked_ranges;
-use proposed_changes_editor::{ProposedChangesBuffer, ProposedChangesEditor};
+pub use proposed_changes_editor::{
+    ProposedChangesBuffer, ProposedChangesEditor, ProposedChangesEditorToolbar,
+};
 use similar::{ChangeTag, TextDiff};
 use task::{ResolvedTask, TaskTemplate, TaskVariables};
 

crates/editor/src/proposed_changes_editor.rs

@@ -6,10 +6,13 @@ use language::{Buffer, BufferEvent, Capability};
 use multi_buffer::{ExcerptRange, MultiBuffer};
 use project::Project;
 use smol::stream::StreamExt;
-use std::{ops::Range, time::Duration};
+use std::{any::TypeId, ops::Range, time::Duration};
 use text::ToOffset;
 use ui::prelude::*;
-use workspace::Item;
+use workspace::{
+    searchable::SearchableItemHandle, Item, ItemHandle as _, ToolbarItemEvent, ToolbarItemLocation,
+    ToolbarItemView,
+};
 
 pub struct ProposedChangesEditor {
     editor: View<Editor>,
@@ -23,6 +26,10 @@ pub struct ProposedChangesBuffer<T> {
     pub ranges: Vec<Range<T>>,
 }
 
+pub struct ProposedChangesEditorToolbar {
+    current_editor: Option<View<ProposedChangesEditor>>,
+}
+
 impl ProposedChangesEditor {
     pub fn new<T: ToOffset>(
         buffers: Vec<ProposedChangesBuffer<T>>,
@@ -96,6 +103,17 @@ impl ProposedChangesEditor {
             self.recalculate_diffs_tx.unbounded_send(buffer).ok();
         }
     }
+
+    fn apply_all_changes(&self, cx: &mut ViewContext<Self>) {
+        let buffers = self.editor.read(cx).buffer.read(cx).all_buffers();
+        for branch_buffer in buffers {
+            if let Some(base_buffer) = branch_buffer.read(cx).diff_base_buffer() {
+                base_buffer.update(cx, |base_buffer, cx| {
+                    base_buffer.merge(&branch_buffer, None, cx)
+                });
+            }
+        }
+    }
 }
 
 impl Render for ProposedChangesEditor {
@@ -122,4 +140,66 @@ impl Item for ProposedChangesEditor {
     fn tab_content_text(&self, _cx: &WindowContext) -> Option<SharedString> {
         Some("Proposed changes".into())
     }
+
+    fn as_searchable(&self, _: &View<Self>) -> Option<Box<dyn SearchableItemHandle>> {
+        Some(Box::new(self.editor.clone()))
+    }
+
+    fn act_as_type<'a>(
+        &'a self,
+        type_id: TypeId,
+        self_handle: &'a View<Self>,
+        _: &'a AppContext,
+    ) -> Option<gpui::AnyView> {
+        if type_id == TypeId::of::<Self>() {
+            Some(self_handle.to_any())
+        } else if type_id == TypeId::of::<Editor>() {
+            Some(self.editor.to_any())
+        } else {
+            None
+        }
+    }
+}
+
+impl ProposedChangesEditorToolbar {
+    pub fn new() -> Self {
+        Self {
+            current_editor: None,
+        }
+    }
+
+    fn get_toolbar_item_location(&self) -> ToolbarItemLocation {
+        if self.current_editor.is_some() {
+            ToolbarItemLocation::PrimaryRight
+        } else {
+            ToolbarItemLocation::Hidden
+        }
+    }
+}
+
+impl Render for ProposedChangesEditorToolbar {
+    fn render(&mut self, _cx: &mut ViewContext<Self>) -> impl IntoElement {
+        let editor = self.current_editor.clone();
+        Button::new("apply-changes", "Apply All").on_click(move |_, cx| {
+            if let Some(editor) = &editor {
+                editor.update(cx, |editor, cx| {
+                    editor.apply_all_changes(cx);
+                });
+            }
+        })
+    }
+}
+
+impl EventEmitter<ToolbarItemEvent> for ProposedChangesEditorToolbar {}
+
+impl ToolbarItemView for ProposedChangesEditorToolbar {
+    fn set_active_pane_item(
+        &mut self,
+        active_pane_item: Option<&dyn workspace::ItemHandle>,
+        _cx: &mut ViewContext<Self>,
+    ) -> workspace::ToolbarItemLocation {
+        self.current_editor =
+            active_pane_item.and_then(|item| item.downcast::<ProposedChangesEditor>());
+        self.get_toolbar_item_location()
+    }
 }

crates/language/src/buffer.rs

@@ -87,7 +87,11 @@ pub type BufferRow = u32;
 #[derive(Clone)]
 enum BufferDiffBase {
     Git(Rope),
-    PastBufferVersion(Model<Buffer>, BufferSnapshot),
+    PastBufferVersion {
+        buffer: Model<Buffer>,
+        rope: Rope,
+        operations_to_ignore: Vec<clock::Lamport>,
+    },
 }
 
 /// An in-memory representation of a source code file, including its text,
@@ -795,19 +799,15 @@ impl Buffer {
         let this = cx.handle();
         cx.new_model(|cx| {
             let mut branch = Self {
-                diff_base: Some(BufferDiffBase::PastBufferVersion(
-                    this.clone(),
-                    self.snapshot(),
-                )),
+                diff_base: Some(BufferDiffBase::PastBufferVersion {
+                    buffer: this.clone(),
+                    rope: self.as_rope().clone(),
+                    operations_to_ignore: Vec::new(),
+                }),
                 language: self.language.clone(),
                 has_conflict: self.has_conflict,
                 has_unsaved_edits: Cell::new(self.has_unsaved_edits.get_mut().clone()),
-                _subscriptions: vec![cx.subscribe(&this, |branch: &mut Self, _, event, cx| {
-                    if let BufferEvent::Operation { operation, .. } = event {
-                        branch.apply_ops([operation.clone()], cx);
-                        branch.diff_base_version += 1;
-                    }
-                })],
+                _subscriptions: vec![cx.subscribe(&this, Self::on_base_buffer_event)],
                 ..Self::build(
                     self.text.branch(),
                     None,
@@ -823,18 +823,74 @@ impl Buffer {
         })
     }
 
-    pub fn merge(&mut self, branch: &Model<Self>, cx: &mut ModelContext<Self>) {
-        let branch = branch.read(cx);
-        let edits = branch
-            .edits_since::<usize>(&self.version)
-            .map(|edit| {
-                (
-                    edit.old,
-                    branch.text_for_range(edit.new).collect::<String>(),
+    /// Applies all of the changes in `branch` buffer that intersect the given `range`
+    /// to this buffer.
+    pub fn merge(
+        &mut self,
+        branch: &Model<Self>,
+        range: Option<Range<Anchor>>,
+        cx: &mut ModelContext<Self>,
+    ) {
+        let edits = branch.read_with(cx, |branch, _| {
+            branch
+                .edits_since_in_range::<usize>(
+                    &self.version,
+                    range.unwrap_or(Anchor::MIN..Anchor::MAX),
                 )
-            })
-            .collect::<Vec<_>>();
-        self.edit(edits, None, cx);
+                .map(|edit| {
+                    (
+                        edit.old,
+                        branch.text_for_range(edit.new).collect::<String>(),
+                    )
+                })
+                .collect::<Vec<_>>()
+        });
+        let operation = self.edit(edits, None, cx);
+
+        // Prevent this operation from being reapplied to the branch.
+        branch.update(cx, |branch, cx| {
+            if let Some(BufferDiffBase::PastBufferVersion {
+                operations_to_ignore,
+                ..
+            }) = &mut branch.diff_base
+            {
+                operations_to_ignore.extend(operation);
+            }
+            cx.emit(BufferEvent::Edited)
+        });
+    }
+
+    fn on_base_buffer_event(
+        &mut self,
+        _: Model<Buffer>,
+        event: &BufferEvent,
+        cx: &mut ModelContext<Self>,
+    ) {
+        if let BufferEvent::Operation { operation, .. } = event {
+            if let Some(BufferDiffBase::PastBufferVersion {
+                operations_to_ignore,
+                ..
+            }) = &mut self.diff_base
+            {
+                let mut is_ignored = false;
+                if let Operation::Buffer(text::Operation::Edit(buffer_operation)) = &operation {
+                    operations_to_ignore.retain(|operation_to_ignore| {
+                        match buffer_operation.timestamp.cmp(&operation_to_ignore) {
+                            Ordering::Less => true,
+                            Ordering::Equal => {
+                                is_ignored = true;
+                                false
+                            }
+                            Ordering::Greater => false,
+                        }
+                    });
+                }
+                if !is_ignored {
+                    self.apply_ops([operation.clone()], cx);
+                    self.diff_base_version += 1;
+                }
+            }
+        }
     }
 
     #[cfg(test)]
@@ -1017,9 +1073,8 @@ impl Buffer {
     /// Returns the current diff base, see [Buffer::set_diff_base].
     pub fn diff_base(&self) -> Option<&Rope> {
         match self.diff_base.as_ref()? {
-            BufferDiffBase::Git(rope) => Some(rope),
-            BufferDiffBase::PastBufferVersion(_, buffer_snapshot) => {
-                Some(buffer_snapshot.as_rope())
+            BufferDiffBase::Git(rope) | BufferDiffBase::PastBufferVersion { rope, .. } => {
+                Some(rope)
             }
         }
     }
@@ -1050,29 +1105,36 @@ impl Buffer {
         self.diff_base_version
     }
 
+    pub fn diff_base_buffer(&self) -> Option<Model<Self>> {
+        match self.diff_base.as_ref()? {
+            BufferDiffBase::Git(_) => None,
+            BufferDiffBase::PastBufferVersion { buffer, .. } => Some(buffer.clone()),
+        }
+    }
+
     /// Recomputes the diff.
     pub fn recalculate_diff(&mut self, cx: &mut ModelContext<Self>) -> Option<Task<()>> {
-        let diff_base_rope = match self.diff_base.as_mut()? {
+        let diff_base_rope = match self.diff_base.as_ref()? {
             BufferDiffBase::Git(rope) => rope.clone(),
-            BufferDiffBase::PastBufferVersion(base_buffer, base_buffer_snapshot) => {
-                let new_base_snapshot = base_buffer.read(cx).snapshot();
-                *base_buffer_snapshot = new_base_snapshot;
-                base_buffer_snapshot.as_rope().clone()
-            }
+            BufferDiffBase::PastBufferVersion { buffer, .. } => buffer.read(cx).as_rope().clone(),
         };
-        let snapshot = self.snapshot();
 
+        let snapshot = self.snapshot();
         let mut diff = self.git_diff.clone();
         let diff = cx.background_executor().spawn(async move {
             diff.update(&diff_base_rope, &snapshot).await;
-            diff
+            (diff, diff_base_rope)
         });
 
         Some(cx.spawn(|this, mut cx| async move {
-            let buffer_diff = diff.await;
+            let (buffer_diff, diff_base_rope) = diff.await;
             this.update(&mut cx, |this, cx| {
                 this.git_diff = buffer_diff;
                 this.non_text_state_update_count += 1;
+                if let Some(BufferDiffBase::PastBufferVersion { rope, .. }) = &mut this.diff_base {
+                    *rope = diff_base_rope;
+                    cx.emit(BufferEvent::DiffBaseChanged);
+                }
                 cx.emit(BufferEvent::DiffUpdated);
             })
             .ok();

crates/language/src/buffer_tests.rs

@@ -2413,80 +2413,98 @@ fn test_branch_and_merge(cx: &mut TestAppContext) {
     });
 
     // Edits to the branch are not applied to the base.
-    branch_buffer.update(cx, |buffer, cx| {
-        buffer.edit(
-            [(Point::new(1, 0)..Point::new(1, 0), "ONE_POINT_FIVE\n")],
+    branch_buffer.update(cx, |branch_buffer, cx| {
+        branch_buffer.edit(
+            [
+                (Point::new(1, 0)..Point::new(1, 0), "1.5\n"),
+                (Point::new(2, 0)..Point::new(2, 5), "THREE"),
+            ],
             None,
             cx,
         )
     });
     branch_buffer.read_with(cx, |branch_buffer, cx| {
         assert_eq!(base_buffer.read(cx).text(), "one\ntwo\nthree\n");
-        assert_eq!(branch_buffer.text(), "one\nONE_POINT_FIVE\ntwo\nthree\n");
+        assert_eq!(branch_buffer.text(), "one\n1.5\ntwo\nTHREE\n");
     });
 
+    // The branch buffer maintains a diff with respect to its base buffer.
+    start_recalculating_diff(&branch_buffer, cx);
+    cx.run_until_parked();
+    assert_diff_hunks(
+        &branch_buffer,
+        cx,
+        &[(1..2, "", "1.5\n"), (3..4, "three\n", "THREE\n")],
+    );
+
     // Edits to the base are applied to the branch.
     base_buffer.update(cx, |buffer, cx| {
         buffer.edit([(Point::new(0, 0)..Point::new(0, 0), "ZERO\n")], None, cx)
     });
     branch_buffer.read_with(cx, |branch_buffer, cx| {
         assert_eq!(base_buffer.read(cx).text(), "ZERO\none\ntwo\nthree\n");
-        assert_eq!(
-            branch_buffer.text(),
-            "ZERO\none\nONE_POINT_FIVE\ntwo\nthree\n"
-        );
+        assert_eq!(branch_buffer.text(), "ZERO\none\n1.5\ntwo\nTHREE\n");
     });
 
-    assert_diff_hunks(&branch_buffer, cx, &[(2..3, "", "ONE_POINT_FIVE\n")]);
+    // Until the git diff recalculation is complete, the git diff references
+    // the previous content of the base buffer, so that it stays in sync.
+    start_recalculating_diff(&branch_buffer, cx);
+    assert_diff_hunks(
+        &branch_buffer,
+        cx,
+        &[(2..3, "", "1.5\n"), (4..5, "three\n", "THREE\n")],
+    );
+    cx.run_until_parked();
+    assert_diff_hunks(
+        &branch_buffer,
+        cx,
+        &[(2..3, "", "1.5\n"), (4..5, "three\n", "THREE\n")],
+    );
 
     // Edits to any replica of the base are applied to the branch.
     base_buffer_replica.update(cx, |buffer, cx| {
-        buffer.edit(
-            [(Point::new(2, 0)..Point::new(2, 0), "TWO_POINT_FIVE\n")],
-            None,
-            cx,
-        )
+        buffer.edit([(Point::new(2, 0)..Point::new(2, 0), "2.5\n")], None, cx)
     });
     branch_buffer.read_with(cx, |branch_buffer, cx| {
-        assert_eq!(
-            base_buffer.read(cx).text(),
-            "ZERO\none\ntwo\nTWO_POINT_FIVE\nthree\n"
-        );
-        assert_eq!(
-            branch_buffer.text(),
-            "ZERO\none\nONE_POINT_FIVE\ntwo\nTWO_POINT_FIVE\nthree\n"
-        );
+        assert_eq!(base_buffer.read(cx).text(), "ZERO\none\ntwo\n2.5\nthree\n");
+        assert_eq!(branch_buffer.text(), "ZERO\none\n1.5\ntwo\n2.5\nTHREE\n");
     });
 
     // Merging the branch applies all of its changes to the base.
     base_buffer.update(cx, |base_buffer, cx| {
-        base_buffer.merge(&branch_buffer, cx);
+        base_buffer.merge(&branch_buffer, None, cx);
+    });
+
+    branch_buffer.update(cx, |branch_buffer, cx| {
         assert_eq!(
-            base_buffer.text(),
-            "ZERO\none\nONE_POINT_FIVE\ntwo\nTWO_POINT_FIVE\nthree\n"
+            base_buffer.read(cx).text(),
+            "ZERO\none\n1.5\ntwo\n2.5\nTHREE\n"
         );
+        assert_eq!(branch_buffer.text(), "ZERO\none\n1.5\ntwo\n2.5\nTHREE\n");
     });
 }
 
+fn start_recalculating_diff(buffer: &Model<Buffer>, cx: &mut TestAppContext) {
+    buffer
+        .update(cx, |buffer, cx| buffer.recalculate_diff(cx).unwrap())
+        .detach();
+}
+
+#[track_caller]
 fn assert_diff_hunks(
     buffer: &Model<Buffer>,
     cx: &mut TestAppContext,
     expected_hunks: &[(Range<u32>, &str, &str)],
 ) {
-    buffer
-        .update(cx, |buffer, cx| buffer.recalculate_diff(cx).unwrap())
-        .detach();
-    cx.executor().run_until_parked();
-
-    buffer.read_with(cx, |buffer, _| {
-        let snapshot = buffer.snapshot();
-        assert_hunks(
-            snapshot.git_diff_hunks_intersecting_range(Anchor::MIN..Anchor::MAX),
-            &snapshot,
-            &buffer.diff_base().unwrap().to_string(),
-            expected_hunks,
-        );
+    let (snapshot, diff_base) = buffer.read_with(cx, |buffer, _| {
+        (buffer.snapshot(), buffer.diff_base().unwrap().to_string())
     });
+    assert_hunks(
+        snapshot.git_diff_hunks_intersecting_range(Anchor::MIN..Anchor::MAX),
+        &snapshot,
+        &diff_base,
+        expected_hunks,
+    );
 }
 
 #[gpui::test(iterations = 100)]

crates/zed/src/zed.rs

@@ -14,6 +14,7 @@ use breadcrumbs::Breadcrumbs;
 use client::ZED_URL_SCHEME;
 use collections::VecDeque;
 use command_palette_hooks::CommandPaletteFilter;
+use editor::ProposedChangesEditorToolbar;
 use editor::{scroll::Autoscroll, Editor, MultiBuffer};
 use feature_flags::FeatureFlagAppExt;
 use gpui::{
@@ -582,6 +583,8 @@ fn initialize_pane(workspace: &mut Workspace, pane: &View<Pane>, cx: &mut ViewCo
             let buffer_search_bar = cx.new_view(search::BufferSearchBar::new);
             toolbar.add_item(buffer_search_bar.clone(), cx);
 
+            let proposed_change_bar = cx.new_view(|_| ProposedChangesEditorToolbar::new());
+            toolbar.add_item(proposed_change_bar, cx);
             let quick_action_bar =
                 cx.new_view(|cx| QuickActionBar::new(buffer_search_bar, workspace, cx));
             toolbar.add_item(quick_action_bar, cx);