fix(lsp): create missing directory before creating file (#19835)

Co-authored-by: Mathias Fussenegger <f.mathias@zignar.net>

runtime/lua/vim/lsp/util.lua

@@ -772,9 +772,12 @@ local function create_file(change)
   -- from spec: Overwrite wins over `ignoreIfExists`
   local fname = vim.uri_to_fname(change.uri)
   if not opts.ignoreIfExists or opts.overwrite then
+    vim.fn.mkdir(vim.fs.dirname(fname), 'p')
     local file = io.open(fname, 'w')
+    if file then
       file:close()
     end
+  end
   vim.fn.bufadd(fname)
 end
 

test/functional/plugin/lsp_spec.lua

@@ -1977,6 +1977,22 @@ describe('LSP', function()
       exec_lua('vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16')
       eq(true, exec_lua('return vim.loop.fs_stat(...) ~= nil', tmpfile))
     end)
+    it('Supports file creation in folder that needs to be created with CreateFile payload', function()
+      local tmpfile = helpers.tmpname()
+      os.remove(tmpfile) -- Should not exist, only interested in a tmpname
+      tmpfile = tmpfile .. '/dummy/x/'
+      local uri = exec_lua('return vim.uri_from_fname(...)', tmpfile)
+      local edit = {
+        documentChanges = {
+          {
+            kind = 'create',
+            uri = uri,
+          },
+        }
+      }
+      exec_lua('vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16')
+      eq(true, exec_lua('return vim.loop.fs_stat(...) ~= nil', tmpfile))
+    end)
     it('createFile does not touch file if it exists and ignoreIfExists is set', function()
       local tmpfile = helpers.tmpname()
       write_file(tmpfile, 'Dummy content')