@@ -247,19 +247,47 @@ impl Client {
247247 .await
248248 }
249249
250+ // TODO: this is dumb. TextEdit describes changes to the initial doc (concurrent), but
251+ // TextDocumentContentChangeEvent describes a series of changes (sequential).
252+ // So S -> S1 -> S2, meaning positioning depends on the previous edits.
253+ //
254+ // Calculation is therefore a bunch trickier.
250255 pub fn changeset_to_changes(
251256 old_text: &Rope,
257+ new_text: &Rope,
252258 changeset: &ChangeSet,
253259 ) -> Vec<lsp::TextDocumentContentChangeEvent> {
254260 let mut iter = changeset.changes().iter().peekable();
255261 let mut old_pos = 0;
262+ let mut new_pos = 0;
256263
257264 let mut changes = Vec::new();
258265
259266 use crate::util::pos_to_lsp_pos;
260267 use helix_core::Operation::*;
261268
269+ // TODO: stolen from syntax.rs, share
270+ use helix_core::RopeSlice;
271+ fn traverse(pos: lsp::Position, text: RopeSlice) -> lsp::Position {
272+ let lsp::Position {
273+ mut line,
274+ mut character,
275+ } = pos;
276+
277+ // TODO: there should be a better way here
278+ for ch in text.chars() {
279+ if ch == '\n' {
280+ line += 1;
281+ character = 0;
282+ } else {
283+ character += ch.len_utf16() as u32;
284+ }
285+ }
286+ lsp::Position { line, character }
287+ }
288+
262289 let old_text = old_text.slice(..);
290+ let new_text = new_text.slice(..);
263291
264292 // TODO: verify this function, specifically line num counting
265293
@@ -271,10 +299,12 @@ impl Client {
271299 let mut old_end = old_pos + len;
272300
273301 match change {
274− Retain(_) => {}
302+ Retain(i) => {
303+ new_pos += i;
304+ }
275305 Delete(_) => {
276− let start = pos_to_lsp_pos(&old_text, old_pos);
277− let end = pos_to_lsp_pos(&old_text, old_end);
306+ let start = pos_to_lsp_pos(&new_text, new_pos);
307+ let end = traverse(start, old_text.slice(old_pos..old_end));
278308
279309 // deletion
280310 changes.push(lsp::TextDocumentContentChangeEvent {
@@ -284,12 +314,14 @@ impl Client {
284314 });
285315 }
286316 Insert(s) => {
287− let start = pos_to_lsp_pos(&old_text, old_pos);
317+ let start = pos_to_lsp_pos(&new_text, new_pos);
318+
319+ new_pos += s.chars().count();
288320
289321 // a subsequent delete means a replace, consume it
290322 let end = if let Some(Delete(len)) = iter.peek() {
291323 old_end = old_pos + len;
292− let end = pos_to_lsp_pos(&old_text, old_end);
324+ let end = traverse(start, old_text.slice(old_pos..old_end));
293325
294326 iter.next();
295327
@@ -318,6 +350,7 @@ impl Client {
318350 &self,
319351 text_document: lsp::VersionedTextDocumentIdentifier,
320352 old_text: &Rope,
353+ new_text: &Rope,
321354 changes: &ChangeSet,
322355 ) -> Result<()> {
323356 // figure out what kind of sync the server supports
@@ -343,7 +376,9 @@ impl Client {
343376 text: "".to_string(),
344377 }] // TODO: probably need old_state here too?
345378 }
346− lsp::TextDocumentSyncKind::Incremental => Self::changeset_to_changes(old_text, changes),
379+ lsp::TextDocumentSyncKind::Incremental => {
380+ Self::changeset_to_changes(old_text, new_text, changes)
381+ }
347382 lsp::TextDocumentSyncKind::None => return Ok(()),
348383 };
349384