bug#46607: 25.2; Emacs hangs with Error running timer 'blink-cursor-start'

[Peter Flynn]

On 18/02/2021 14:05, Eli Zaretskii wrote:
[...]
> Please try "emacs -q" (lower-case "q", not "Q").  If the problem
> happens with -q as well, then its cause is somewhere in all those
> site-start.d/50*.el files Emacs loads at startup -- those come from
> your system's Emacs distro.

On a bare-bones Mint 19 with no .emacs and using emacs -Q (capital Q) 
the *messages* buffer contains:

> For information about GNU Emacs and the GNU system, type C-h C-a.
> Type C-x 1 to delete the help window.
> mwheel-scroll: End of buffer
> mwheel-scroll: Beginning of buffer [7 times]
> Note: file is write protected
> View mode: type C-h for help, h for commands, q to quit.
> Mark set
> Checking for load-path shadows...
> Checking 255 files in /usr/share/emacs/25.2/lisp...
> Checking 41 files in /usr/share/emacs/25.2/lisp/vc...
> Checking 33 files in /usr/share/emacs/25.2/lisp/url...
> Checking 44 files in /usr/share/emacs/25.2/lisp/textmodes...
> Checking 87 files in /usr/share/emacs/25.2/lisp/progmodes...
> Checking 25 files in /usr/share/emacs/25.2/lisp/play...
> Checking 106 files in /usr/share/emacs/25.2/lisp/org...
> Checking 24 files in /usr/share/emacs/25.2/lisp/nxml...
> Checking 66 files in /usr/share/emacs/25.2/lisp/net...
> Checking 26 files in /usr/share/emacs/25.2/lisp/mh-e...
> Checking 34 files in /usr/share/emacs/25.2/lisp/mail...
> Checking 1 files in /usr/share/emacs/25.2/lisp/leim...
> Checking 38 files in /usr/share/emacs/25.2/lisp/language...
> Checking 43 files in /usr/share/emacs/25.2/lisp/international...
> Checking 130 files in /usr/share/emacs/25.2/lisp/gnus...
> Checking 29 files in /usr/share/emacs/25.2/lisp/eshell...
> Checking 35 files in /usr/share/emacs/25.2/lisp/erc...
> Checking 17 files in /usr/share/emacs/25.2/lisp/emulation...
> Checking 84 files in /usr/share/emacs/25.2/lisp/emacs-lisp...
> Checking 12 files in /usr/share/emacs/25.2/lisp/cedet...
> Checking 30 files in /usr/share/emacs/25.2/lisp/calendar...
> Checking 44 files in /usr/share/emacs/25.2/lisp/calc...
> Checking 60 files in /usr/share/emacs/25.2/lisp/obsolete...
> Checking for load-path shadows...done
> Auto-saving...done

With emacs -q (lowercase) it never gets as far as the banner screen or 
the scratch buffer. Instead, the message area at the bottom just says

> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5)

The *messages* buffer contains:

> Loading 00debian-vars...done
> Loading /etc/emacs/site-start.d/50asymptote.el (source)...done
> Loading /etc/emacs/site-start.d/50autoconf.el (source)...done
> Loading /etc/emacs/site-start.d/50cmake-data.el (source)...done
> Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...
> Loading debian-ispell...
> Loading /var/cache/dictionaries-common/emacsen-ispell-default.el (source)...done
> Loading debian-ispell...done
> Loading /var/cache/dictionaries-common/emacsen-ispell-dicts.el (source)...done
> Loading /etc/emacs/site-start.d/50dictionaries-common.el (source)...done
> Loading /etc/emacs/site-start.d/50latex-cjk-common.el (source)...
> Loading cjk-enc...done
> Loading /etc/emacs/site-start.d/50latex-cjk-common.el (source)...done
> Loading /etc/emacs/site-start.d/50latex-cjk-thai.el (source)...done
> Loading /etc/emacs/site-start.d/50texlive-lang-english.el (source)...done
> For information about GNU Emacs and the GNU system, type C-h C-a.
> setq: Wrong type argument: listp, 10
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5)
> setq: Wrong type argument: listp, 0.7
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5) [2 
> times]
> setq: Wrong type argument: listp, 0.7 [3 times]
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5) [3 
> times]
> setq: Wrong type argument: listp, 0.7
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5) [3 
> times]
> setq: Wrong type argument: listp, 0.7 [4 times]
> mwheel-scroll: Beginning of buffer [13 times]
> setq: Wrong type argument: listp, 0.35 [3 times]
> mwheel-scroll: End of buffer [3 times]
> setq: Wrong type argument: listp, 0.35 [3 times]
> mwheel-scroll: Beginning of buffer [3 times]
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5) [3 
> times]
> setq: Wrong type argument: listp, 0.7 [2 times]
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5)
> Mark set
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5) [2 
> times]
> progn: Buffer is read-only: #<buffer *Messages*>
> w is undefined
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5) [7 
> times]
> Mark activated
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5)
> next-line: End of buffer [8 times]
> Error running timer ‘blink-cursor-start’: (wrong-type-argument listp 0.5)

All those errors are the results of mouse-button clicks.

Peter