when enabling cider-font-lock-dynamically, regexp highlights are not displayed

[scramjet]

Expected behavior

Using highlight-regexp to highlight a regexp, or highlighting with the highlight-symbol package, I expect the requested symbol to be highlighted with background colour.

Actual behaviour

Sometimes the highlights are not displayed.

With highlight-symbol, the failure is accompanied by this error in *Messages*:

Error during redisplay: (jit-lock-function 6057) signaled (invalid-regexp "Regular expression too big")

Steps to reproduce the problem

1. (setq cider-font-lock-dynamically t)
2. Load a Clojure or ClojureScript file.
3. Use highlight-regexp (M-s h r) to try to highlight a regexp
4. Nno highlight is displayed

Unfortunately I haven't worked out how to reliably trigger, it just happens on some files. (setq cider-font-lock-dynamically nil) and reloading fixes, and it doesn't happen if the file is not require'd by anything. It seems to happen more often with CLJS.

Environment & Version information

clojure-mode (version 5.19.0)

CIDER version information

;; CIDER 1.16.1 (Kherson), nREPL 1.0.0
;; Clojure 1.11.1, Java 14.0.2

Lein / Clojure CLI version

Leiningen 2.9.5

Emacs version

GNU Emacs 29.1 (build 1, aarch64-apple-darwin24.1.0, Carbon Version 170 AppKit 2575.2) of 2024-11-28

Operating system

macOS 15.3.2

JDK distribution

OpenJDK Runtime Environment AdoptOpenJDK (build 14.0.2+12)