Show excerpt dividers in without_headers multibuffers (#36647)

Release Notes:

- Fixed diff cards in agent threads not showing dividers between
disjoint edited regions.

crates/editor/src/display_map/block_map.rs

@@ -290,7 +290,10 @@ pub enum Block {
     ExcerptBoundary {
         excerpt: ExcerptInfo,
         height: u32,
-        starts_new_buffer: bool,
+    },
+    BufferHeader {
+        excerpt: ExcerptInfo,
+        height: u32,
     },
 }
 
@@ -303,27 +306,37 @@ impl Block {
                 ..
             } => BlockId::ExcerptBoundary(next_excerpt.id),
             Block::FoldedBuffer { first_excerpt, .. } => BlockId::FoldedBuffer(first_excerpt.id),
+            Block::BufferHeader {
+                excerpt: next_excerpt,
+                ..
+            } => BlockId::ExcerptBoundary(next_excerpt.id),
         }
     }
 
     pub fn has_height(&self) -> bool {
         match self {
             Block::Custom(block) => block.height.is_some(),
-            Block::ExcerptBoundary { .. } | Block::FoldedBuffer { .. } => true,
+            Block::ExcerptBoundary { .. }
+            | Block::FoldedBuffer { .. }
+            | Block::BufferHeader { .. } => true,
         }
     }
 
     pub fn height(&self) -> u32 {
         match self {
             Block::Custom(block) => block.height.unwrap_or(0),
-            Block::ExcerptBoundary { height, .. } | Block::FoldedBuffer { height, .. } => *height,
+            Block::ExcerptBoundary { height, .. }
+            | Block::FoldedBuffer { height, .. }
+            | Block::BufferHeader { height, .. } => *height,
         }
     }
 
     pub fn style(&self) -> BlockStyle {
         match self {
             Block::Custom(block) => block.style,
-            Block::ExcerptBoundary { .. } | Block::FoldedBuffer { .. } => BlockStyle::Sticky,
+            Block::ExcerptBoundary { .. }
+            | Block::FoldedBuffer { .. }
+            | Block::BufferHeader { .. } => BlockStyle::Sticky,
         }
     }
 
@@ -332,6 +345,7 @@ impl Block {
             Block::Custom(block) => matches!(block.placement, BlockPlacement::Above(_)),
             Block::FoldedBuffer { .. } => false,
             Block::ExcerptBoundary { .. } => true,
+            Block::BufferHeader { .. } => true,
         }
     }
 
@@ -340,6 +354,7 @@ impl Block {
             Block::Custom(block) => matches!(block.placement, BlockPlacement::Near(_)),
             Block::FoldedBuffer { .. } => false,
             Block::ExcerptBoundary { .. } => false,
+            Block::BufferHeader { .. } => false,
         }
     }
 
@@ -351,6 +366,7 @@ impl Block {
             ),
             Block::FoldedBuffer { .. } => false,
             Block::ExcerptBoundary { .. } => false,
+            Block::BufferHeader { .. } => false,
         }
     }
 
@@ -359,6 +375,7 @@ impl Block {
             Block::Custom(block) => matches!(block.placement, BlockPlacement::Replace(_)),
             Block::FoldedBuffer { .. } => true,
             Block::ExcerptBoundary { .. } => false,
+            Block::BufferHeader { .. } => false,
         }
     }
 
@@ -367,6 +384,7 @@ impl Block {
             Block::Custom(_) => false,
             Block::FoldedBuffer { .. } => true,
             Block::ExcerptBoundary { .. } => true,
+            Block::BufferHeader { .. } => true,
         }
     }
 
@@ -374,9 +392,8 @@ impl Block {
         match self {
             Block::Custom(_) => false,
             Block::FoldedBuffer { .. } => true,
-            Block::ExcerptBoundary {
+            Block::ExcerptBoundary { .. } => false,
-                starts_new_buffer, ..
+            Block::BufferHeader { .. } => true,
-            } => *starts_new_buffer,
         }
     }
 }
@@ -393,14 +410,14 @@ impl Debug for Block {
                 .field("first_excerpt", &first_excerpt)
                 .field("height", height)
                 .finish(),
-            Self::ExcerptBoundary {
+            Self::ExcerptBoundary { excerpt, height } => f
-                starts_new_buffer,
-                excerpt,
-                height,
-            } => f
                 .debug_struct("ExcerptBoundary")
                 .field("excerpt", excerpt)
-                .field("starts_new_buffer", starts_new_buffer)
+                .field("height", height)
+                .finish(),
+            Self::BufferHeader { excerpt, height } => f
+                .debug_struct("BufferHeader")
+                .field("excerpt", excerpt)
                 .field("height", height)
                 .finish(),
         }
@@ -662,13 +679,11 @@ impl BlockMap {
                     }),
             );
 
-            if buffer.show_headers() {
             blocks_in_edit.extend(self.header_and_footer_blocks(
                 buffer,
                 (start_bound, end_bound),
                 wrap_snapshot,
             ));
-            }
 
             BlockMap::sort_blocks(&mut blocks_in_edit);
 
@@ -771,7 +786,7 @@ impl BlockMap {
                     if self.buffers_with_disabled_headers.contains(&new_buffer_id) {
                         continue;
                     }
-                    if self.folded_buffers.contains(&new_buffer_id) {
+                    if self.folded_buffers.contains(&new_buffer_id) && buffer.show_headers() {
                         let mut last_excerpt_end_row = first_excerpt.end_row;
 
                         while let Some(next_boundary) = boundaries.peek() {
@@ -804,20 +819,24 @@ impl BlockMap {
                     }
                 }
 
-                if new_buffer_id.is_some() {
+                let starts_new_buffer = new_buffer_id.is_some();
+                let block = if starts_new_buffer && buffer.show_headers() {
                     height += self.buffer_header_height;
-                } else {
+                    Block::BufferHeader {
-                    height += self.excerpt_header_height;
+                        excerpt: excerpt_boundary.next,
+                        height,
                     }
-
+                } else if excerpt_boundary.prev.is_some() {
-                return Some((
+                    height += self.excerpt_header_height;
-                    BlockPlacement::Above(WrapRow(wrap_row)),
                     Block::ExcerptBoundary {
                         excerpt: excerpt_boundary.next,
                         height,
-                        starts_new_buffer: new_buffer_id.is_some(),
+                    }
-                    },
+                } else {
-                ));
+                    continue;
+                };
+
+                return Some((BlockPlacement::Above(WrapRow(wrap_row)), block));
             }
         })
     }
@@ -842,13 +861,25 @@ impl BlockMap {
                     (
                         Block::ExcerptBoundary {
                             excerpt: excerpt_a, ..
+                        }
+                        | Block::BufferHeader {
+                            excerpt: excerpt_a, ..
                         },
                         Block::ExcerptBoundary {
                             excerpt: excerpt_b, ..
+                        }
+                        | Block::BufferHeader {
+                            excerpt: excerpt_b, ..
                         },
                     ) => Some(excerpt_a.id).cmp(&Some(excerpt_b.id)),
-                    (Block::ExcerptBoundary { .. }, Block::Custom(_)) => Ordering::Less,
+                    (
-                    (Block::Custom(_), Block::ExcerptBoundary { .. }) => Ordering::Greater,
+                        Block::ExcerptBoundary { .. } | Block::BufferHeader { .. },
+                        Block::Custom(_),
+                    ) => Ordering::Less,
+                    (
+                        Block::Custom(_),
+                        Block::ExcerptBoundary { .. } | Block::BufferHeader { .. },
+                    ) => Ordering::Greater,
                     (Block::Custom(block_a), Block::Custom(block_b)) => block_a
                         .priority
                         .cmp(&block_b.priority)
@@ -1377,7 +1408,9 @@ impl BlockSnapshot {
 
         while let Some(transform) = cursor.item() {
             match &transform.block {
-                Some(Block::ExcerptBoundary { excerpt, .. }) => {
+                Some(
+                    Block::ExcerptBoundary { excerpt, .. } | Block::BufferHeader { excerpt, .. },
+                ) => {
                     return Some(StickyHeaderExcerpt { excerpt });
                 }
                 Some(block) if block.is_buffer_header() => return None,

crates/editor/src/element.rs

@@ -2749,7 +2749,10 @@ impl EditorElement {
         let mut block_offset = 0;
         let mut found_excerpt_header = false;
         for (_, block) in snapshot.blocks_in_range(prev_line..row_range.start) {
-            if matches!(block, Block::ExcerptBoundary { .. }) {
+            if matches!(
+                block,
+                Block::ExcerptBoundary { .. } | Block::BufferHeader { .. }
+            ) {
                 found_excerpt_header = true;
                 break;
             }
@@ -2766,7 +2769,10 @@ impl EditorElement {
         let mut block_height = 0;
         let mut found_excerpt_header = false;
         for (_, block) in snapshot.blocks_in_range(row_range.end..cons_line) {
-            if matches!(block, Block::ExcerptBoundary { .. }) {
+            if matches!(
+                block,
+                Block::ExcerptBoundary { .. } | Block::BufferHeader { .. }
+            ) {
                 found_excerpt_header = true;
             }
             block_height += block.height();
@@ -3452,18 +3458,29 @@ impl EditorElement {
                     .into_any_element()
             }
 
-            Block::ExcerptBoundary {
+            Block::ExcerptBoundary { .. } => {
-                excerpt,
-                height,
-                starts_new_buffer,
-                ..
-            } => {
                 let color = cx.theme().colors().clone();
                 let mut result = v_flex().id(block_id).w_full();
 
+                result = result.child(
+                    h_flex().relative().child(
+                        div()
+                            .top(line_height / 2.)
+                            .absolute()
+                            .w_full()
+                            .h_px()
+                            .bg(color.border_variant),
+                    ),
+                );
+
+                result.into_any()
+            }
+
+            Block::BufferHeader { excerpt, height } => {
+                let mut result = v_flex().id(block_id).w_full();
+
                 let jump_data = header_jump_data(snapshot, block_row_start, *height, excerpt);
 
-                if *starts_new_buffer {
                 if sticky_header_excerpt_id != Some(excerpt.id) {
                     let selected = selected_buffer_ids.contains(&excerpt.buffer_id);
 
@@ -3476,18 +3493,6 @@ impl EditorElement {
                     result =
                         result.child(div().h(FILE_HEADER_HEIGHT as f32 * window.line_height()));
                 }
-                } else {
-                    result = result.child(
-                        h_flex().relative().child(
-                            div()
-                                .top(line_height / 2.)
-                                .absolute()
-                                .w_full()
-                                .h_px()
-                                .bg(color.border_variant),
-                        ),
-                    );
-                };
 
                 result.into_any()
             }
@@ -5708,7 +5713,10 @@ impl EditorElement {
                     let end_row_in_current_excerpt = snapshot
                         .blocks_in_range(start_row..end_row)
                         .find_map(|(start_row, block)| {
-                            if matches!(block, Block::ExcerptBoundary { .. }) {
+                            if matches!(
+                                block,
+                                Block::ExcerptBoundary { .. } | Block::BufferHeader { .. }
+                            ) {
                                 Some(start_row)
                             } else {
                                 None

crates/editor/src/test.rs

@@ -230,12 +230,12 @@ pub fn editor_content_with_blocks(editor: &Entity<Editor>, cx: &mut VisualTestCo
                     lines[row as usize].push_str("§ -----");
                 }
             }
-            Block::ExcerptBoundary {
+            Block::ExcerptBoundary { height, .. } => {
-                excerpt,
+                for row in row.0..row.0 + height {
-                height,
+                    lines[row as usize].push_str("§ -----");
-                starts_new_buffer,
+                }
-            } => {
+            }
-                if starts_new_buffer {
+            Block::BufferHeader { excerpt, height } => {
                 lines[row.0 as usize].push_str(&cx.update(|_, cx| {
                     format!(
                         "§ {}",
@@ -247,9 +247,6 @@ pub fn editor_content_with_blocks(editor: &Entity<Editor>, cx: &mut VisualTestCo
                             .to_string_lossy()
                     )
                 }));
-                } else {
-                    lines[row.0 as usize].push_str("§ -----")
-                }
                 for row in row.0 + 1..row.0 + height {
                     lines[row as usize].push_str("§ -----");
                 }