feat: anchor review comments to precise text ranges

src/editor_review.rs

@@ -341,14 +341,24 @@ impl Editor {
             .filter(|_| self.diff_interacting())
             .ok_or("Focus a diff text pane to add a comment")?;
         if self.selection_count() != 1 {
-            return Err("Use one caret or one line range for a review comment".into());
+            return Err("Use one caret or one contiguous selection for a review comment".into());
         }
-        let selection = self.selections().into_iter().next();
-        let (first, last) = selection.map_or((self.cursor().row, self.cursor().row), |selection| {
-            let last = selection.end.row.saturating_sub(usize::from(
-                selection.end.column == 0 && selection.end.row > selection.start.row,
-            ));
-            (selection.start.row, last)
+        let range = self.selections().into_iter().next().unwrap_or_else(|| {
+            let row = self.cursor().row;
+            Selection {
+                start: Cursor { row, column: 0 },
+                end: if row + 1 < self.active.lines.len() {
+                    Cursor {
+                        row: row + 1,
+                        column: 0,
+                    }
+                } else {
+                    Cursor {
+                        row,
+                        column: grapheme_count(&self.active.lines[row]),
+                    }
+                },
+            }
         });
         let diff = self.diff.as_ref().unwrap();
         let comparison = diff.comparison.as_ref().unwrap();
@@ -367,8 +377,14 @@ impl Editor {
             }
             .clone(),
             side,
-            start_line: first + 1,
-            end_line: last + 1,
+            start: TextPosition {
+                row: range.start.row,
+                column: range.start.column,
+            },
+            end: TextPosition {
+                row: range.end.row,
+                column: range.end.column,
+            },
             content: self.active.lines.join("\n"),
         };
         let id = diff
@@ -405,10 +421,12 @@ impl Editor {
         let text = comment.body.clone();
         let anchor = &comment.anchor;
         let title = format!(
-            "Comment #{id} · {}:{}–{} · {:?} · :w saves review",
+            "Comment #{id} · {}:{}:{}–{}:{} · {:?} · :w saves review",
             anchor.path.display(),
-            anchor.start_line,
-            anchor.end_line,
+            anchor.start.row + 1,
+            anchor.start.column + 1,
+            anchor.end.row + 1,
+            anchor.end.column + 1,
             anchor.side
         );
         let target = diff.comparison.as_ref().and_then(|comparison| {
@@ -479,16 +497,16 @@ impl Editor {
             self.set_message("Comment is stale; original snapshot anchor preserved");
             return;
         }
-        let row = comment.anchor.start_line - 1;
+        let position = comment.anchor.start;
         let focus = if comment.anchor.side == Side::Before {
             Focus::Before
         } else {
             Focus::After
         };
         diff.focus = focus;
-        diff.reveal_source_row(focus, row);
+        diff.reveal_source_row(focus, position.row);
         self.bind_diff_buffer();
-        self.place_navigation(TextPosition { row, column: 0 });
+        self.place_navigation(position);
     }
 
     fn open_review_overview(&mut self) -> Result<(), String> {
@@ -529,11 +547,13 @@ impl Editor {
             use std::fmt::Write as _;
             write!(
                 text,
-                "\n## Comment #{} · {status}\n{}:{}–{} · {:?}\nRevision: {}\n{}\n",
+                "\n## Comment #{} · {status}\n{}:{}:{}–{}:{} · {:?}\nRevision: {}\n{}\n",
                 comment.id,
                 anchor.path.display(),
-                anchor.start_line,
-                anchor.end_line,
+                anchor.start.row + 1,
+                anchor.start.column + 1,
+                anchor.end.row + 1,
+                anchor.end.column + 1,
                 anchor.side,
                 anchor.revision,
                 comment.body