From 8dda8f21de93f57e6a85792848adce2b42cba655 Mon Sep 17 00:00:00 2001
From: Tom van Ommeren <tom.vanommeren@gmail.com>
Date: Sat, 14 Sep 2019 13:52:14 +0200
Subject: [PATCH] Create a new line for edits after the document (#717)

* Create a new line for edits after the document

* Switch to iterable, lint fix, update test comments

* Revert use of iterator - typings don't agree

* Update last_row and log when appending a line
---
 plugin/core/edit.py      |  8 ++------
 plugin/core/test_edit.py | 10 +++++-----
 plugin/edit.py           | 14 ++++++++++++--
 tests/test_edit.py       | 23 +++++++++++++++++++++++
 4 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/plugin/core/edit.py b/plugin/core/edit.py
index 0b62a0376..16d81b39d 100644
--- a/plugin/core/edit.py
+++ b/plugin/core/edit.py
@@ -1,4 +1,5 @@
 from .url import uri_to_filename
+import operator
 try:
     from typing import List, Dict, Optional, Any, Iterable, Tuple
     TextEdit = Tuple[Tuple[int, int], Tuple[int, int], str]
@@ -32,11 +33,6 @@ def parse_text_edit(text_edit: 'Dict[str, Any]') -> 'TextEdit':
 
 
 def sort_by_application_order(changes: 'Iterable[TextEdit]') -> 'List[TextEdit]':
-
-    def get_start_position(pair: 'Tuple[int, TextEdit]'):
-        index, change = pair
-        return change[0][0], change[0][1], index
-
     # The spec reads:
     # > However, it is possible that multiple edits have the same start position: multiple
     # > inserts, or any number of inserts followed by a single remove or replace edit. If
@@ -45,4 +41,4 @@ def get_start_position(pair: 'Tuple[int, TextEdit]'):
     # So we sort by start position. But if multiple text edits start at the same position,
     # we use the index in the array as the key.
 
-    return list(map(lambda pair: pair[1], sorted(enumerate(changes), key=get_start_position, reverse=True)))
+    return list(sorted(changes, key=operator.itemgetter(0)))
diff --git a/plugin/core/test_edit.py b/plugin/core/test_edit.py
index 0bc0670c2..9103064fd 100644
--- a/plugin/core/test_edit.py
+++ b/plugin/core/test_edit.py
@@ -58,14 +58,14 @@ class SortByApplicationOrderTests(unittest.TestCase):
     def test_empty_sort(self):
         self.assertEqual(sort_by_application_order([]), [])
 
-    def test_sorts_backwards(self):
+    def test_sorts_in_application_order(self):
         edits = [
             ((0, 0), (0, 0), 'b'),
             ((0, 0), (0, 0), 'a'),
             ((0, 2), (0, 2), 'c')
         ]
         # expect 'c' (higher start), 'a' now reverse order before 'b'
-        sorted = sort_by_application_order(edits)
-        self.assertEqual(sorted[0][2], 'c')
-        self.assertEqual(sorted[1][2], 'a')
-        self.assertEqual(sorted[2][2], 'b')
+        sorted_edits = sort_by_application_order(edits)
+        self.assertEqual(sorted_edits[0][2], 'b')
+        self.assertEqual(sorted_edits[1][2], 'a')
+        self.assertEqual(sorted_edits[2][2], 'c')
diff --git a/plugin/edit.py b/plugin/edit.py
index 535b1e4fd..bfd3ccb31 100644
--- a/plugin/edit.py
+++ b/plugin/edit.py
@@ -41,14 +41,24 @@ def open_and_apply_edits(self, path, file_changes):
 
 
 class LspApplyDocumentEditCommand(sublime_plugin.TextCommand):
+
     def run(self, edit, changes: 'Optional[List[TextEdit]]' = None):
         # Apply the changes in reverse, so that we don't invalidate the range
         # of any change that we haven't applied yet.
         if changes:
-            for change in sort_by_application_order(changes):
+            last_row, last_col = self.view.rowcol(self.view.size())
+            for change in reversed(sort_by_application_order(changes)):
                 start, end, newText = change
                 region = sublime.Region(self.view.text_point(*start), self.view.text_point(*end))
-                self.apply_change(region, newText, edit)
+
+                if start[0] > last_row and newText[0] != '\n':
+                    # Handle when a language server (eg gopls) inserts at a row beyond the document
+                    # some editors create the line automatically, sublime needs to have the newline prepended.
+                    debug('adding new line for edit at line {}, document ended at line {}'.format(start[0], last_row))
+                    self.apply_change(region, '\n' + newText, edit)
+                    last_row, last_col = self.view.rowcol(self.view.size())
+                else:
+                    self.apply_change(region, newText, edit)
 
     def apply_change(self, region: 'sublime.Region', newText: str, edit):
         if region.empty():
diff --git a/tests/test_edit.py b/tests/test_edit.py
index 95566cd08..c0f36cbe3 100644
--- a/tests/test_edit.py
+++ b/tests/test_edit.py
@@ -13,6 +13,29 @@ class ApplyDocumentEditTests(DeferrableTestCase):
     def setUp(self):
         self.view = sublime.active_window().new_file()
 
+    def test_remove_line_and_then_insert_at_that_line_at_end(self):
+        original = (
+            'a\n'
+            'b\n'
+            'c'
+        )
+        file_changes = [
+            ((2, 0), (3, 0), ''),  # out-of-bounds end position, but this is fine
+            ((3, 0), (3, 0), 'c\n')  # out-of-bounds start and end, this line doesn't exist
+        ]
+        expected = (
+            'a\n'
+            'b\n'
+            'c\n'
+        )
+        # Old behavior:
+        # 1) first we end up with ('a\n', 'b\n', 'cc\n')
+        # 2) then we end up with ('a\n', 'b\n', '')
+        # New behavior:
+        # 1) line index 3 is "created" ('a\n', 'b\n', 'c\n', c\n'))
+        # 2) deletes line index 2.
+        self.run_test(original, expected, file_changes)
+
     def test_apply(self):
         original = (
             '<dom-module id="some-thing">\n'