From eb690735784ba162e68d9fb9ab3704feae126e24 Mon Sep 17 00:00:00 2001
From: Henrik Lissner <henrik@lissner.net>
Date: Thu, 27 Feb 2020 21:47:32 -0500
Subject: [PATCH] Fix infinite redrawing/freezing with {centaur,awesome}-tabs

Caused by over-zealous doom-switch-window-hook.

For my own sanity (and if you're curious), I'll break it down here:

1. Doom has a `doom-switch-window-hook` hook. It triggers when window
   focus is changed.
2. We use `buffer-list-update-hook` to trigger
   `doom-switch-window-hook`. (That may sound weird, but this hook is
   reliably executed when window focus is changed -- there are
   safeguards to prevent this from triggering too often)
3. `buffer-list-update-hook` triggers whenever a buffer is created, but
   `doom-switch-window-hook` only triggers if the created buffer is in
   a new window.
4. The use of `with-temp-buffer` in `centaur-tabs-line-format` counts as
   "buffer creation" in a "new window".
5. `+vc-gutter-update-h` is in `doom-switch-window-hook`. This refreshes
   git-gutter, which initiates a redraw of Emacs.
6. When Emacs redraws, it recalculates its mode and header lines. which
   triggers `doom-switch-window-hook` once, which triggers
   `+vc-gutter-update-h`, which redraws the screen, then Emacs recalculates
   the header line, running `centaur-tabs-line-format`...

Infinite loop ensues

Hopefully fixes:
- hlissner/doom-emacs#2436
- ema2159/centaur-tabs#18
- ema2159/centaur-tabs#88
---
 core/core-ui.el                | 9 ++++++---
 modules/ui/vc-gutter/config.el | 3 ++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/core/core-ui.el b/core/core-ui.el
index 6592485ec..faf5309f9 100644
--- a/core/core-ui.el
+++ b/core/core-ui.el
@@ -89,7 +89,8 @@ size.")
     (unless (or doom-inhibit-switch-window-hooks
                 (eq doom--last-window (selected-window))
                 (minibufferp))
-      (let ((doom-inhibit-switch-window-hooks t))
+      (let ((doom-inhibit-switch-window-hooks t)
+            (inhibit-redisplay t))
         (run-hooks 'doom-switch-window-hook)
         (setq doom--last-window (selected-window))))))
 
@@ -107,7 +108,8 @@ size.")
             (eq (current-buffer) (get-buffer buffer-or-name))
             (and (eq orig-fn #'switch-to-buffer) (car args)))
         (apply orig-fn buffer-or-name args)
-      (let ((doom-inhibit-switch-buffer-hooks t))
+      (let ((doom-inhibit-switch-buffer-hooks t)
+            (inhibit-redisplay t))
         (when-let (buffer (apply orig-fn buffer-or-name args))
           (with-current-buffer (if (windowp buffer)
                                    (window-buffer buffer)
@@ -119,7 +121,8 @@ size.")
   (let ((gc-cons-threshold most-positive-fixnum))
     (if doom-inhibit-switch-buffer-hooks
         (apply orig-fn args)
-      (let ((doom-inhibit-switch-buffer-hooks t))
+      (let ((doom-inhibit-switch-buffer-hooks t)
+            (inhibit-redisplay t))
         (when-let (buffer (apply orig-fn args))
           (with-current-buffer buffer
             (run-hooks 'doom-switch-buffer-hook))
diff --git a/modules/ui/vc-gutter/config.el b/modules/ui/vc-gutter/config.el
index d310a82b8..075fb0005 100644
--- a/modules/ui/vc-gutter/config.el
+++ b/modules/ui/vc-gutter/config.el
@@ -71,7 +71,8 @@ is deferred until the file is saved. Respects `git-gutter:disabled-modes'."
 `doom-escape-hook' hooks."
       (when (and git-gutter-mode
                  (not (memq this-command '(git-gutter:stage-hunk
-                                           git-gutter:revert-hunk))))
+                                           git-gutter:revert-hunk)))
+                 (not inhibit-redisplay))
         (ignore (git-gutter)))))
   ;; update git-gutter when using magit commands
   (advice-add #'magit-stage-file   :after #'+vc-gutter-update-h)