fix(lsp): account for changedtick version gap on modified reset (#29170)

Follow up to https://github.com/neovim/neovim/pull/28943
Fixes https://github.com/neovim/neovim/issues/29163

2 files changed, 16 insertions, 13 deletions

diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index b33f6ccf69..3215b40d1d 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -502,6 +502,11 @@ function M.apply_text_document_edit(text_document_edit, index, offset_encoding)
     should_check_version = false
   end
 
+  -- changedtick increases on save but server only receives version updates
+  -- on line changes (via didChange)
+  -- This allows a gap of 1 to account for the servers outdated view
+  local version_offset = vim.b[bufnr].modified and 0 or 1
+
   -- `VersionedTextDocumentIdentifier`s version may be null
   --  https://microsoft.github.io/language-server-protocol/specification#versionedTextDocumentIdentifier
   if
@@ -509,7 +514,7 @@ function M.apply_text_document_edit(text_document_edit, index, offset_encoding)
     and (
       text_document.version
       and text_document.version > 0
-      and vim.b[bufnr].changedtick > text_document.version
+      and vim.b[bufnr].changedtick > (text_document.version + version_offset)
     )
   then
     print('Buffer ', text_document.uri, ' newer than edits.')
diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index 85891e59b5..23f6b733d5 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -2133,15 +2133,13 @@ describe('LSP', function()
       }, buf_lines(target_bufnr))
     end)
     it('skips the edit if the version of the edit is behind the local buffer ', function()
-      local apply_edit_mocking_current_version = function(edit, versionedBuf)
+      local apply_edit_mocking_current_version = function(edit)
         exec_lua(
           [[
           local args = {...}
-          local versionedBuf = args[2]
           vim.lsp.util.apply_text_document_edit(args[1], nil, 'utf-16')
         ]],
-          edit,
-          versionedBuf
+          edit
         )
       end
 
@@ -2153,17 +2151,17 @@ describe('LSP', function()
       eq(baseText, buf_lines(target_bufnr))
 
       -- Apply an edit for an old version, should skip
-      apply_edit_mocking_current_version(
-        text_document_edit(2),
-        { currentVersion = 7, bufnr = target_bufnr }
-      )
+      apply_edit_mocking_current_version(text_document_edit(1))
       eq(baseText, buf_lines(target_bufnr)) -- no change
 
       -- Sanity check that next version to current does apply change
-      apply_edit_mocking_current_version(
-        text_document_edit(8),
-        { currentVersion = 7, bufnr = target_bufnr }
-      )
+      apply_edit_mocking_current_version(text_document_edit(exec_lua(
+        [[
+          local bufnr = ...
+          return vim.b[bufnr].changedtick
+        ]],
+        target_bufnr
+      )))
       eq({
         'First ↥ 🤦 🦄 line of text',
         '2nd line of 语text',