feat(lsp): support textDocument/prepareRename (#15514)

runtime/lua/vim/lsp/buf.lua

@@ -249,13 +249,34 @@ end
 ---@param new_name (string) If not provided, the user will be prompted for a new
 ---name using |input()|.
 function M.rename(new_name)
-  -- TODO(ashkan) use prepareRename
-  -- * result: [`Range`](#range) \| `{ range: Range, placeholder: string }` \| `null` describing the range of the string to rename and optionally a placeholder text of the string content to be renamed. If `null` is returned then it is deemed that a 'textDocument/rename' request is not valid at the given position.
   local params = util.make_position_params()
+  local function prepare_rename(err, result)
+    if err == nil and result == nil then
+      vim.notify('nothing to rename', vim.log.levels.INFO)
+      return
+    end
+    if result and result.placeholder then
+      new_name = new_name or npcall(vfn.input, "New Name: ", result.placeholder)
+    elseif result and result.start and result['end'] and
+      result.start.line == result['end'].line then
+      local line = vfn.getline(result.start.line+1)
+      local start_char = result.start.character+1
+      local end_char = result['end'].character
+      new_name = new_name or npcall(vfn.input, "New Name: ", string.sub(line, start_char, end_char))
+    else
+      -- fallback to guessing symbol using <cword>
+      --
+      -- this can happen if the language server does not support prepareRename,
+      -- returns an unexpected response, or requests for "default behavior"
+      --
+      -- see https://microsoft.github.io/language-server-protocol/specification#textDocument_prepareRename
       new_name = new_name or npcall(vfn.input, "New Name: ", vfn.expand('<cword>'))
+    end
     if not (new_name and #new_name > 0) then return end
     params.newName = new_name
     request('textDocument/rename', params)
+  end
+  request('textDocument/prepareRename', params, prepare_rename)
 end
 
 --- Lists all the references to the symbol under the cursor in the quickfix window.

test/functional/fixtures/fake-lsp-server.lua

@@ -126,6 +126,89 @@ function tests.check_workspace_configuration()
   }
 end
 
+function tests.prepare_rename_nil()
+  skeleton {
+    on_init = function()
+      return { capabilities = {
+        renameProvider = true,
+      } }
+    end;
+    body = function()
+      notify('start')
+      expect_request('textDocument/prepareRename', function()
+        return nil, nil
+      end)
+      notify('shutdown')
+    end;
+  }
+end
+
+function tests.prepare_rename_placeholder()
+  skeleton {
+    on_init = function()
+      return { capabilities = {
+        renameProvider = true,
+      } }
+    end;
+    body = function()
+      notify('start')
+      expect_request('textDocument/prepareRename', function()
+        return nil, {placeholder = 'placeholder'}
+      end)
+      expect_request('textDocument/rename', function(params)
+        assert_eq(params.newName, 'renameto')
+        return nil, nil
+      end)
+      notify('shutdown')
+    end;
+  }
+end
+
+function tests.prepare_rename_range()
+  skeleton {
+    on_init = function()
+      return { capabilities = {
+        renameProvider = true,
+      } }
+    end;
+    body = function()
+      notify('start')
+      expect_request('textDocument/prepareRename', function()
+        return nil, {
+          start = { line = 1, character = 8 },
+          ['end'] = { line = 1, character = 12 },
+        }
+      end)
+      expect_request('textDocument/rename', function(params)
+        assert_eq(params.newName, 'renameto')
+        return nil, nil
+      end)
+      notify('shutdown')
+    end;
+  }
+end
+
+function tests.prepare_rename_error()
+  skeleton {
+    on_init = function()
+      return { capabilities = {
+        renameProvider = true,
+      } }
+    end;
+    body = function()
+      notify('start')
+      expect_request('textDocument/prepareRename', function()
+        return {}, nil
+      end)
+      expect_request('textDocument/rename', function(params)
+        assert_eq(params.newName, 'renameto')
+        return nil, nil
+      end)
+      notify('shutdown')
+    end;
+  }
+end
+
 function tests.basic_check_capabilities()
   skeleton {
     on_init = function(params)

test/functional/plugin/lsp_spec.lua

@@ -2202,4 +2202,90 @@ describe('LSP', function()
       eq(expected, qflist)
     end)
   end)
+
+  describe('vim.lsp.buf.rename', function()
+    for _, test in ipairs({
+      {
+        it = "does not attempt to rename on nil response",
+        name = "prepare_rename_nil",
+        expected_handlers = {
+          {NIL, {}, {method="shutdown", client_id=1}};
+          {NIL, {}, {method="start", client_id=1}};
+        },
+      },
+      {
+        it = "handles prepareRename placeholder response",
+        name = "prepare_rename_placeholder",
+        expected_handlers = {
+          {NIL, {}, {method="shutdown", client_id=1}};
+          {NIL, NIL, {method="textDocument/rename", client_id=1, bufnr=1}};
+          {NIL, {}, {method="start", client_id=1}};
+        },
+        expected_text = "placeholder", -- see fake lsp response
+      },
+      {
+        it = "handles range response",
+        name = "prepare_rename_range",
+        expected_handlers = {
+          {NIL, {}, {method="shutdown", client_id=1}};
+          {NIL, NIL, {method="textDocument/rename", client_id=1, bufnr=1}};
+          {NIL, {}, {method="start", client_id=1}};
+        },
+        expected_text = "line", -- see test case and fake lsp response
+      },
+      {
+        it = "handles error",
+        name = "prepare_rename_error",
+        expected_handlers = {
+          {NIL, {}, {method="shutdown", client_id=1}};
+          {NIL, NIL, {method="textDocument/rename", client_id=1, bufnr=1}};
+          {NIL, {}, {method="start", client_id=1}};
+        },
+        expected_text = "two", -- see test case
+      },
+    }) do
+    it(test.it, function()
+      local client
+      test_rpc_server {
+        test_name = test.name;
+        on_init = function(_client)
+          client = _client
+          eq(true, client.resolved_capabilities().rename)
+        end;
+        on_setup = function()
+          exec_lua([=[
+            local bufnr = vim.api.nvim_get_current_buf()
+            lsp.buf_attach_client(bufnr, TEST_RPC_CLIENT_ID)
+            vim.lsp._stubs = {}
+            vim.fn.input = function(prompt, text)
+              vim.lsp._stubs.input_prompt = prompt
+              vim.lsp._stubs.input_text = text
+              return 'renameto' -- expect this value in fake lsp
+            end
+            vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, {'', 'this is line two'})
+            vim.fn.cursor(2, 13) -- the space between "line" and "two"
+          ]=])
+        end;
+        on_exit = function(code, signal)
+          eq(0, code, "exit code", fake_lsp_logfile)
+          eq(0, signal, "exit signal", fake_lsp_logfile)
+        end;
+        on_handler = function(err, result, ctx)
+          eq(table.remove(test.expected_handlers), {err, result, ctx}, "expected handler")
+          if ctx.method == 'start' then
+            exec_lua("vim.lsp.buf.rename()")
+          end
+          if ctx.method == 'shutdown' then
+            if test.expected_text then
+              eq("New Name: ", exec_lua("return vim.lsp._stubs.input_prompt"))
+              eq(test.expected_text, exec_lua("return vim.lsp._stubs.input_text"))
+            end
+            client.stop()
+          end
+        end;
+      }
+    end)
+    end
+  end)
+
 end)