Eglot: protect against nil jit-lock-context-unfontify-pos

* lisp/progmodes/eglot.el (eglot-shutdown, eglot--update-hints): Rework.

Github-reference: https://github.com/joaotavora/eglot/pull/1370
(cherry picked from commit b685b21a33423018f3da7695919a4d1b1ef2c9cd)

diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
index f22add70a767b7e2c374bb47feb57beaf83ab4d0..1329903d64746100396376dfde09c3b96564d154 100644 (file)
--- a/lisp/progmodes/eglot.el
+++ b/lisp/progmodes/eglot.el
@@ -4320,47 +4320,47 @@ If NOERROR, return predicate, else erroring function."
 (defvar-local eglot--outstanding-inlay-regions-timer nil
   "Helper timer for `eglot--update-hints'.")
 
-(defun eglot--update-hints (from to)
+(cl-defun eglot--update-hints (from to)
   "Jit-lock function for Eglot inlay hints."
+  ;; XXX: We're relying on knowledge of jit-lock internals here.
+  ;; Comparing `jit-lock-context-unfontify-pos' (if non-nil) to
+  ;; `point-max' tells us whether this call to `jit-lock-functions'
+  ;; happens after `jit-lock-context-timer' has just run.
+  (when (and jit-lock-context-unfontify-pos
+             (/= jit-lock-context-unfontify-pos (point-max)))
+    (cl-return-from eglot--update-hints))
   (cl-symbol-macrolet ((region eglot--outstanding-inlay-hints-region)
                        (last-region eglot--outstanding-inlay-hints-last-region)
                        (timer eglot--outstanding-inlay-regions-timer))
     (setcar region (min (or (car region) (point-max)) from))
     (setcdr region (max (or (cdr region) (point-min)) to))
-    ;; HACK: We're relying on knowledge of jit-lock internals here.  The
-    ;; condition comparing `jit-lock-context-unfontify-pos' to
-    ;; `point-max' is a heuristic for telling whether this call to
-    ;; `jit-lock-functions' happens after `jit-lock-context-timer' has
-    ;; just run.  Only after this delay should we start the smoothing
-    ;; timer that will eventually call `eglot--update-hints-1' with the
-    ;; coalesced region.  I wish we didn't need the timer, but sometimes
-    ;; a lot of "non-contextual" calls come in all at once and do verify
-    ;; the condition.  Notice it is a 0 second timer though, so we're
-    ;; not introducing any more delay over jit-lock's timers.
-    (when (= jit-lock-context-unfontify-pos (point-max))
-      (if timer (cancel-timer timer))
-      (let ((buf (current-buffer)))
-        (setq timer (run-at-time
-                     0 nil
-                     (lambda ()
-                       (eglot--when-live-buffer buf
-                         ;; HACK: In some pathological situations
-                         ;; (Emacs's own coding.c, for example),
-                         ;; jit-lock is calling `eglot--update-hints'
-                         ;; repeatedly with same sequence of
-                         ;; arguments, which leads to
-                         ;; `eglot--update-hints-1' being called with
-                         ;; the same region repeatedly.  This happens
-                         ;; even if the hint-painting code does
-                         ;; nothing else other than widen, narrow,
-                         ;; move point then restore these things.
-                         ;; Possible Emacs bug, but this fixes it.
-                         (unless (equal last-region region)
-                           (eglot--update-hints-1 (max (car region) (point-min))
-                                                  (min (cdr region) (point-max)))
-                           (setq last-region region))
-                         (setq region (cons nil nil)
-                               timer nil)))))))))
+    ;; XXX: Then there is a smoothing timer.  I wish we didn't need it,
+    ;; but sometimes a lot of calls come in all at once and do make it
+    ;; past the check above.  Notice it is a 0 second timer though, so
+    ;; we're not introducing any more delay over jit-lock's timers.
+    (when timer (cancel-timer timer))
+    (setq timer (run-at-time
+                 0 nil
+                 (lambda (buf)
+                   (eglot--when-live-buffer buf
+                     ;; HACK: In some pathological situations
+                     ;; (Emacs's own coding.c, for example),
+                     ;; jit-lock is calling `eglot--update-hints'
+                     ;; repeatedly with same sequence of
+                     ;; arguments, which leads to
+                     ;; `eglot--update-hints-1' being called with
+                     ;; the same region repeatedly.  This happens
+                     ;; even if the hint-painting code does
+                     ;; nothing else other than widen, narrow,
+                     ;; move point then restore these things.
+                     ;; Possible Emacs bug, but this fixes it.
+                     (unless (equal last-region region)
+                       (eglot--update-hints-1 (max (car region) (point-min))
+                                              (min (cdr region) (point-max)))
+                       (setq last-region region))
+                     (setq region (cons nil nil)
+                           timer nil)))
+                 (current-buffer)))))
 
 (defun eglot--update-hints-1 (from to)
   "Do most work for `eglot--update-hints', including LSP request."