refactor!(indent-guides): use indent-bars instead

BREAKING CHANGE: This swaps out the `highlight-indent-guides` package
with the newer, and proportedly faster, `indent-bars`. Users don't have
to make any changes to their config to support this, unless they've
heavily reconfigured `highlight-indent-guides`.

Ref: https://github.com/orgs/doomemacs/projects/5/views/1?filterQuery=-status%3ARejected%2CDone+indent&pane=issue&itemId=38113671

modules/config/default/+emacs-bindings.el

@@ -334,7 +334,7 @@
        (:when (modulep! :checkers syntax)
         :desc "Flycheck"                   "f" #'flycheck-mode)
        (:when (modulep! :ui indent-guides)
-        :desc "Indent guides"              "i" #'highlight-indent-guides-mode)
+        :desc "Indent guides"              "i" #'indent-bars-mode)
        (:when (modulep! :ui minimap)
         :desc "Minimap mode"               "m" #'minimap-mode)
        (:when (modulep! :lang org +present)

modules/config/default/+evil-bindings.el

@@ -843,7 +843,7 @@
        :desc "Frame fullscreen"             "F" #'toggle-frame-fullscreen
        :desc "Evil goggles"                 "g" #'evil-goggles-mode
        (:when (modulep! :ui indent-guides)
-        :desc "Indent guides"              "i" #'highlight-indent-guides-mode)
+        :desc "Indent guides"              "i" #'indent-bars-mode)
        :desc "Indent style"                 "I" #'doom/toggle-indent-style
        :desc "Line numbers"                 "l" #'doom/toggle-line-numbers
        (:when (modulep! :ui minimap)

modules/ui/indent-guides/README.org

@@ -13,7 +13,7 @@
 /This module has no flags./
 
 ** Packages
-- [[doom-package:highlight-indent-guides]]
+- [[doom-package:indent-bars]]
 
 ** Hacks
 /No hacks documented for this module./

modules/ui/indent-guides/config.el

@@ -1,11 +1,10 @@
 ;;; ui/indent-guides/config.el -*- lexical-binding: t; -*-
 
-(defcustom +indent-guides-inhibit-functions nil
+(defcustom +indent-guides-inhibit-functions ()
   "A list of predicate functions.
 
-Each function will be run in the context of a buffer where
-`highlight-indent-guides-mode' should be enabled. If any function returns
-non-nil, the mode will not be activated."
+Each function will be run in the context of a buffer where `indent-bars' should
+be enabled. If any function returns non-nil, the mode will not be activated."
   :type 'hook
   :group '+indent-guides)
 
@@ -13,17 +12,25 @@ non-nil, the mode will not be activated."
 ;;
 ;;; Packages
 
-(use-package! highlight-indent-guides
+(use-package! indent-bars
   :hook ((prog-mode text-mode conf-mode) . +indent-guides-init-maybe-h)
   :init
-  (setq highlight-indent-guides-method 'character
-        highlight-indent-guides-bitmap-function #'highlight-indent-guides--bitmap-line)
-
   (defun +indent-guides-init-maybe-h ()
-    "Enable `highlight-indent-guides-mode'.
-Consults `+indent-guides-inhibit-functions'."
+    "Enable `indent-bars-mode' depending on `+indent-guides-inhibit-functions'."
     (unless (run-hook-with-args-until-success '+indent-guides-inhibit-functions)
-      (highlight-indent-guides-mode +1)))
+      (indent-bars-mode +1)))
+  :config
+  ;; Bitmap performance is inconsistent across display systems (pgtk, ns, mac,
+  ;; gtk, etc). There's also a bitmap init bug in PGTK builds of Emacs before
+  ;; v30 that could cause crashes (see jdtsmith/indent-bars#3). If you use PGTK
+  ;; and reverse this setting, you've been warned!
+  (setq indent-bars-prefer-character t)
+
+  ;; TODO: Uncomment once we support treesit
+  ;; (setq indent-bars-treesit-support (modulep! :tools tree-sitter))
+
+  (unless (boundp 'enable-theme-functions)
+    (add-hook 'doom-load-theme-hook #'indent-bars-reset-styles))
 
   (add-hook! '+indent-guides-inhibit-functions
     ;; Org's virtual indentation messes up indent-guides.
@@ -33,12 +40,23 @@ Consults `+indent-guides-inhibit-functions'."
     ;; notebooks.
     (defun +indent-guides-in-ein-notebook-p ()
       (and (bound-and-true-p ein:notebook-mode)
-           (bound-and-true-p ein:output-area-inlined-images))))
-  :config
-  ;; HACK: If this package is loaded too early (by the user, and in terminal
-  ;;   Emacs), then `highlight-indent-guides-auto-set-faces' will have been
-  ;;   called much too early to set its faces correctly. To get around this, we
-  ;;   need to call it again, but at a time when I can ensure a frame exists an
-  ;;   the current theme is loaded.
-  (when (doom-context-p 'init)
-    (add-hook 'doom-first-buffer-hook #'highlight-indent-guides-auto-set-faces)))
+           (bound-and-true-p ein:output-area-inlined-images)))
+    ;; Don't display indent guides in childframe popups (not helpful in
+    ;; completion or eldoc popups).
+    ;; REVIEW: Swap with `frame-parent' when 27 support is dropped
+    (defun +indent-guides-in-childframe-p ()
+      (frame-parameter nil 'parent-frame)))
+
+  ;; HACK: Out of the box, indent-bars offers no way to fully disable
+  ;;   "highlighting the current line", so I advise on in, since the feature is
+  ;;   unnecessary work (and allocation of timers) for users that don't want it,
+  ;;   and for our performance-leaning defaults.
+  (setq indent-bars-depth-update-delay nil)
+  (defadvice! +indent-guides--disable-highlight-current-line-a (fn &rest args)
+    :around #'indent-bars-setup
+    (letf! (defun indent-bars--highlight-current-depth ()
+             (when indent-bars-depth-update-delay
+               (funcall indent-bars--highlight-current-depth)))
+      (prog1 (apply fn args)
+        (unless indent-bars-depth-update-delay
+          (remove-hook 'post-command-hook #'indent-bars--highlight-current-depth t))))))

modules/ui/indent-guides/packages.el

@@ -1,4 +1,6 @@
 ;; -*- no-byte-compile: t; -*-
 ;;; ui/indent-guides/packages.el
 
-(package! highlight-indent-guides :pin "cf352c85cd15dd18aa096ba9d9ab9b7ab493e8f6")
+(package! indent-bars
+  :recipe (:host github :repo "jdtsmith/indent-bars")
+   :pin "c8376cf4373a6444ca88e88736db7576dedb51d6")