From 57ed5180e0e1af3b3ddcb478c4a6d6ecd969cd40 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Mon, 6 Sep 2021 11:00:33 +0900
Subject: [PATCH] lsp: Improve line ending handling when generating TextEdit

---
 helix-lsp/src/client.rs    | 10 +++++++---
 helix-view/src/document.rs | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index fd34f45d2..52b2c1c99 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -3,7 +3,7 @@ use crate::{
     Call, Error, OffsetEncoding, Result,
 };
 
-use helix_core::{chars::char_is_line_ending, find_root, ChangeSet, Rope};
+use helix_core::{find_root, ChangeSet, Rope};
 use jsonrpc_core as jsonrpc;
 use lsp_types as lsp;
 use serde_json::Value;
@@ -356,7 +356,6 @@ impl Client {
         //
         // Calculation is therefore a bunch trickier.
 
-        // TODO: stolen from syntax.rs, share
         use helix_core::RopeSlice;
         fn traverse(pos: lsp::Position, text: RopeSlice) -> lsp::Position {
             let lsp::Position {
@@ -366,7 +365,12 @@ impl Client {
 
             let mut chars = text.chars().peekable();
             while let Some(ch) = chars.next() {
-                if char_is_line_ending(ch) && !(ch == '\r' && chars.peek() == Some(&'\n')) {
+                // LSP only considers \n, \r or \r\n as line endings
+                if ch == '\n' || ch == '\r' {
+                    // consume a \r\n
+                    if chars.peek() == Some(&'\n') {
+                        chars.next();
+                    }
                     line += 1;
                     character = 0;
                 } else {
diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index e890a3366..b2c029275 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -891,6 +891,40 @@ impl Default for Document {
 mod test {
     use super::*;
 
+    #[test]
+    fn changeset_to_changes_ignore_line_endings() {
+        use helix_lsp::{lsp, Client, OffsetEncoding};
+        let text = Rope::from("hello\r\nworld");
+        let mut doc = Document::from(text, None);
+        let view = ViewId::default();
+        doc.set_selection(view, Selection::single(0, 0));
+
+        let transaction =
+            Transaction::change(doc.text(), vec![(5, 7, Some("\n".into()))].into_iter());
+        let old_doc = doc.text().clone();
+        doc.apply(&transaction, view);
+        let changes = Client::changeset_to_changes(
+            &old_doc,
+            doc.text(),
+            transaction.changes(),
+            OffsetEncoding::Utf8,
+        );
+
+        assert_eq!(doc.text(), "hello\nworld");
+
+        assert_eq!(
+            changes,
+            &[lsp::TextDocumentContentChangeEvent {
+                range: Some(lsp::Range::new(
+                    lsp::Position::new(0, 5),
+                    lsp::Position::new(1, 0)
+                )),
+                text: "\n".into(),
+                range_length: None,
+            }]
+        );
+    }
+
     #[test]
     fn changeset_to_changes() {
         use helix_lsp::{lsp, Client, OffsetEncoding};