From c5dd2847ffafd41f4f652983959c491dfbf2e362 Mon Sep 17 00:00:00 2001
From: Henrik Lissner <git@henrik.io>
Date: Thu, 22 May 2025 19:32:30 +0200
Subject: [PATCH] feat(scala): add treesit support

---
 modules/lang/scala/README.org       |  3 +-
 modules/lang/scala/config.el        | 62 +++++++++++++++++++----------
 modules/lang/scala/doctor.el        |  4 ++
 modules/lang/scala/packages.el      |  4 ++
 modules/tools/tree-sitter/config.el |  1 -
 5 files changed, 52 insertions(+), 22 deletions(-)

diff --git a/modules/lang/scala/README.org b/modules/lang/scala/README.org
index e6107a387..d22a6ab77 100644
--- a/modules/lang/scala/README.org
+++ b/modules/lang/scala/README.org
@@ -30,11 +30,12 @@ Through the power of [[https://scalameta.org/metals/docs/editors/overview.html][
   (supports metals).
 - +tree-sitter ::
   Leverages tree-sitter for better syntax highlighting and structural text
-  editing. Requires [[doom-module::tools tree-sitter]].
+  editing. Requires Emacs 29.1+ and [[doom-module::tools tree-sitter]].
 
 ** Packages
 - [[doom-package:sbt-mode]]
 - [[doom-package:scala-mode]]
+- [[doom-package:scala-ts-mode]] if [[doom-module:+tree-sitter]]
 - [[doom-package:lsp-metals]] if [[doom-module:+lsp]]
 
 ** Hacks
diff --git a/modules/lang/scala/config.el b/modules/lang/scala/config.el
index d42e879db..80a9ed0f0 100644
--- a/modules/lang/scala/config.el
+++ b/modules/lang/scala/config.el
@@ -7,24 +7,12 @@
 ;;
 ;;; Packages
 
-(after! scala-mode
-  (setq scala-indent:align-parameters t
-        ;; indent block comments to first asterix, not second
-        scala-indent:use-javadoc-style t)
-
-  (setq-hook! 'scala-mode-hook
-    comment-line-break-function #'+scala-comment-indent-new-line-fn)
-
-  (when (modulep! +lsp)
-    (setq-hook! 'scala-mode-hook lsp-enable-indentation nil)
-    (add-hook 'scala-mode-local-vars-hook #'lsp! 'append))
-
-  (when (modulep! +tree-sitter)
-    (add-hook 'scala-mode-local-vars-hook #'tree-sitter! 'append))
-
-  (set-formatter! 'scalafmt '("scalafmt" "--stdin") :modes '(scala-mode))
-
-  (set-ligatures! 'scala-mode
+(defun +scala-common-config (mode)
+  (set-formatter! 'scalafmt '("scalafmt" "--stdin")
+    :modes (list mode))
+  (set-repl-handler! mode #'+scala/open-repl
+    :persist t)
+  (set-ligatures! mode
     ;; Functional
     :def "def"
     :composition  "compose"
@@ -49,9 +37,43 @@
     ;; Other
     :union        "union"
     :intersect    "intersect"
-    :diff         "diff"))
+    :diff         "diff")
+
+  (when (modulep! +lsp)
+    (add-hook (intern (format "%s-local-vars-hook" mode)) #'lsp! 'append)))
+
+
+(after! scala-mode
+  (setq scala-indent:align-parameters t
+        ;; indent block comments to first asterix, not second
+        scala-indent:use-javadoc-style t)
+
+  (setq-hook! 'scala-mode-hook
+    comment-line-break-function #'+scala-comment-indent-new-line-fn
+    lsp-enable-indentation nil)
+
+  (+scala-common-config 'scala-mode))
+
+
+(use-package! scala-ts-mode
+  :when (modulep! +tree-sitter)
+  :when (fboundp 'treesit-available-p)
+  :defer t
+  :init
+  (set-tree-sitter! 'scala-mode 'scala-ts-mode
+    '((scala :url "https://github.com/tree-sitter/tree-sitter-scala")))
+
+  :config
+  (when (modulep! +lsp)
+    (setq-hook! 'scala-ts-mode-hook lsp-enable-indentation nil)
+    (add-hook 'scala-ts-mode-local-vars-hook #'lsp! 'append))
+
+  ;; HACK: Rely on `major-mode-remap-defaults'.
+  (cl-callf2 assq-delete-all 'scala-ts-mode auto-mode-alist)
+
+  (+scala-common-config 'scala-ts-mode))
 
 
 (use-package! sbt-mode
   :after scala-mode
-  :config (set-repl-handler! 'scala-mode #'+scala/open-repl :persist t))
+  :config (set-repl-handler! '(scala-mode scala-ts-mode) #'+scala/open-repl :persist t))
diff --git a/modules/lang/scala/doctor.el b/modules/lang/scala/doctor.el
index fc72e2f18..4ba6b07d2 100644
--- a/modules/lang/scala/doctor.el
+++ b/modules/lang/scala/doctor.el
@@ -8,6 +8,10 @@
              (modulep! :tools tree-sitter))
          "This module requires (:tools tree-sitter)")
 
+(assert! (or (not (modulep! +tree-sitter))
+             (version< emacs-version "29.1"))
+         "Emacs 29.1+ is required for tree-sitter support")
+
 (if (and (modulep! +lsp)
          (not (executable-find "metals")))
     (warn! "metals isn't installed"))
diff --git a/modules/lang/scala/packages.el b/modules/lang/scala/packages.el
index 6289243ff..ea3e43fa5 100644
--- a/modules/lang/scala/packages.el
+++ b/modules/lang/scala/packages.el
@@ -4,6 +4,10 @@
 (package! sbt-mode :pin "cc68728a6ef0600aad369157b3a2d0ce56afba9b")
 (package! scala-mode :pin "661337d8aa0a0cb418184c83757661603de3b2e3")
 
+(when (and (modulep! +tree-sitter)
+           (fboundp 'treesit-available-p))
+  (package! scala-ts-mode :pin "c7671e10419261ef70b1820d3b970ad39f6fcfe2"))
+
 (when (and (modulep! +lsp)
            (modulep! :tools lsp -eglot))
   (package! lsp-metals :pin "e1d9d04f3bab7e6e74916054b36ab1a87e831367"))
diff --git a/modules/tools/tree-sitter/config.el b/modules/tools/tree-sitter/config.el
index d74a8a3c2..2bd9cb31c 100644
--- a/modules/tools/tree-sitter/config.el
+++ b/modules/tools/tree-sitter/config.el
@@ -42,7 +42,6 @@
                  (proto "https://github.com/mitchellh/tree-sitter-proto" nil nil nil nil)
                  (r "https://github.com/r-lib/tree-sitter-r" nil nil nil nil)
                  (rust "https://github.com/tree-sitter/tree-sitter-rust" nil nil nil nil)
-                 (scala "https://github.com/tree-sitter/tree-sitter-scala" nil nil nil nil)
                  (sql "https://github.com/DerekStride/tree-sitter-sql" "gh-pages" nil nil nil)
                  (surface "https://github.com/connorlay/tree-sitter-surface" nil nil nil nil)
                  (toml "https://github.com/tree-sitter/tree-sitter-toml" nil nil nil nil)