fix(lsp): restore marks after apply_text_edits() #14630

PROBLEM:
Whenever any text edits are applied to the buffer, the `marks` part of those
lines will be lost. This is mostly problematic for code formatters that format
the whole buffer like `prettier`, `luafmt`, ...

When doing atomic changes inside a vim doc, vim keeps track of those changes and
can update the positions of marks accordingly, but in this case we have a whole
doc that changed. There's no simple way to update the positions of all marks
from the previous document state to the new document state.

SOLUTION:
* save marks right before `nvim_buf_set_lines` is called inside `apply_text_edits`
* check if any marks were lost after doing `nvim_buf_set_lines`
* restore those marks to the previous positions

TEST CASE:
* have a formatter enabled
* open any file
* create a couple of marks
* indent the whole file to the right
* save the file
Before this change: all marks will be removed.
After this change: they will be preserved.

Fixes #14307

1 files changed, 48 insertions, 0 deletions

diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index 26fd2276fd..72a9bc45a2 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -1679,6 +1679,54 @@ describe('LSP', function()
         'foobar';
       }, buf_lines(1))
     end)
+    it('it restores marks', function()
+      local edits = {
+        make_edit(1, 0, 2, 5, "foobar");
+        make_edit(4, 0, 5, 0, "barfoo");
+      }
+      eq(true, exec_lua('return vim.api.nvim_buf_set_mark(1, "a", 2, 1, {})'))
+      exec_lua('vim.lsp.util.apply_text_edits(...)', edits, 1, "utf-16")
+      eq({
+        'First line of text';
+        'foobar line of text';
+        'Fourth line of text';
+        'barfoo';
+      }, buf_lines(1))
+      local mark = exec_lua('return vim.api.nvim_buf_get_mark(1, "a")')
+      eq({ 2, 1 }, mark)
+    end)
+
+    it('it restores marks to last valid col', function()
+      local edits = {
+        make_edit(1, 0, 2, 15, "foobar");
+        make_edit(4, 0, 5, 0, "barfoo");
+      }
+      eq(true, exec_lua('return vim.api.nvim_buf_set_mark(1, "a", 2, 10, {})'))
+      exec_lua('vim.lsp.util.apply_text_edits(...)', edits, 1, "utf-16")
+      eq({
+        'First line of text';
+        'foobarext';
+        'Fourth line of text';
+        'barfoo';
+      }, buf_lines(1))
+      local mark = exec_lua('return vim.api.nvim_buf_get_mark(1, "a")')
+      eq({ 2, 9 }, mark)
+    end)
+
+    it('it restores marks to last valid line', function()
+      local edits = {
+        make_edit(1, 0, 4, 5, "foobar");
+        make_edit(4, 0, 5, 0, "barfoo");
+      }
+      eq(true, exec_lua('return vim.api.nvim_buf_set_mark(1, "a", 4, 1, {})'))
+      exec_lua('vim.lsp.util.apply_text_edits(...)', edits, 1, "utf-16")
+      eq({
+        'First line of text';
+        'foobaro';
+      }, buf_lines(1))
+      local mark = exec_lua('return vim.api.nvim_buf_get_mark(1, "a")')
+      eq({ 2, 1 }, mark)
+    end)
 
     describe('cursor position', function()
       it('don\'t fix the cursor if the range contains the cursor', function()