Fix switch statement indentation for go-ts-mode (bug#61238)

* lisp/progmodes/go-ts-mode.el (go-ts-mode--indent-rules): Add
indentation for type switch and select case blocks
* test/lisp/progmodes/go-ts-mode-resources/indent.erts: New .erts file
to test indentation of Go constructs and prevent regression of bug
fixes.
* test/lisp/progmodes/go-ts-mode-tests.el: New file with go-ts-mode
tests.

3 files changed, 82 insertions, 0 deletions

diff --git a/lisp/progmodes/go-ts-mode.el b/lisp/progmodes/go-ts-mode.el
index 5f3e1ea3e68..95dcf653fc6 100644
--- a/lisp/progmodes/go-ts-mode.el
+++ b/lisp/progmodes/go-ts-mode.el
@@ -72,6 +72,7 @@
      ((node-is "labeled_statement") no-indent)
      ((parent-is "argument_list") parent-bol go-ts-mode-indent-offset)
      ((parent-is "block") parent-bol go-ts-mode-indent-offset)
+     ((parent-is "communication_case") parent-bol go-ts-mode-indent-offset)
      ((parent-is "const_declaration") parent-bol go-ts-mode-indent-offset)
      ((parent-is "default_case") parent-bol go-ts-mode-indent-offset)
      ((parent-is "expression_case") parent-bol go-ts-mode-indent-offset)
@@ -82,7 +83,10 @@
      ((parent-is "labeled_statement") parent-bol go-ts-mode-indent-offset)
      ((parent-is "literal_value") parent-bol go-ts-mode-indent-offset)
      ((parent-is "parameter_list") parent-bol go-ts-mode-indent-offset)
+     ((parent-is "select_statement") parent-bol 0)
+     ((parent-is "type_case") parent-bol go-ts-mode-indent-offset)
      ((parent-is "type_spec") parent-bol go-ts-mode-indent-offset)
+     ((parent-is "type_switch_statement") parent-bol 0)
      ((parent-is "var_declaration") parent-bol go-ts-mode-indent-offset)
      (no-node parent-bol 0)))
   "Tree-sitter indent rules for `go-ts-mode'.")
diff --git a/test/lisp/progmodes/go-ts-mode-resources/indent.erts b/test/lisp/progmodes/go-ts-mode-resources/indent.erts
new file mode 100644
index 00000000000..a89d69b307c
--- /dev/null
+++ b/test/lisp/progmodes/go-ts-mode-resources/indent.erts
@@ -0,0 +1,47 @@
+Code:
+  (lambda ()
+    (go-ts-mode)
+    (indent-region (point-min) (point-max)))
+
+Point-Char: |
+
+Name: Basic
+
+=-=
+package main
+
+func main() {
+}
+=-=-=
+
+Name: Switch and Select
+
+=-=
+package main
+
+func main() {
+        var x any
+        switch x {
+        case 1:
+                println("one")
+        default:
+                println("default case")
+        }
+
+        switch x.(type) {
+        case int:
+                println("integer")
+        default:
+                println("don't know the type")
+        }
+
+        var c chan int
+        select {
+        case x := <-c:
+                println(x)
+        default:
+                println("no communication")
+        }
+}
+
+=-=-=
diff --git a/test/lisp/progmodes/go-ts-mode-tests.el b/test/lisp/progmodes/go-ts-mode-tests.el
new file mode 100644
index 00000000000..548465208f9
--- /dev/null
+++ b/test/lisp/progmodes/go-ts-mode-tests.el
@@ -0,0 +1,31 @@
+;;; go-ts-mode-tests.el --- Tests for Tree-sitter-based Go mode         -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2023 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'ert-x)
+(require 'treesit)
+
+(ert-deftest go-ts-mode-test-indentation ()
+  (skip-unless (treesit-ready-p 'go))
+  (ert-test-erts-file (ert-resource-file "indent.erts")))
+
+(provide 'go-ts-mode-tests)
+;;; go-ts-mode-tests.el ends here