bug#65116: 29.1; query-replace-read-args fails reading second arg in detached minibuf

[Eli Zaretskii]

> Date: Sun, 14 Jan 2024 10:59:16 -0600
> From: Jim Rees <jim@rees.org>
> Cc: acm@muc.de, luangruo@yahoo.com, 65116@debbugs.gnu.org
> 
> What happens first is the mouse pointer disappears, but I can still edit.
> After a while emacs hangs and ignores all input. A bit later it won't even
> redisplay frames on X exposure.
> 
> Here is the stack when it hangs:
> 
> % sudo gdb -batch -ex bt -p 174496
> [New LWP 174497]
> [New LWP 174498]
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/usr/lib/libthread_db.so.1".
> 0x00007f7f6ee3e9d8 in pthread_sigmask () from /usr/lib/libc.so.6
> #0  0x00007f7f6ee3e9d8 in pthread_sigmask () at /usr/lib/libc.so.6
> #1  0x000055e30363ed64 in block_interrupt_signal ()
> #2  0x000055e3036d3a2a in really_call_select ()
> #3  0x000055e3036d3ee9 in thread_select ()
> #4  0x000055e3036ec3e4 in xg_select ()
> #5  0x000055e3036baaa2 in wait_reading_process_output ()
> #6  0x000055e303634352 in read_char ()
> #7  0x000055e303635b0d in read_key_sequence ()
> #8  0x000055e303636999 in command_loop_1 ()
> #9  0x000055e3036870a9 in internal_condition_case ()
> #10 0x000055e30362a3d2 in command_loop_2 ()
> #11 0x000055e303687027 in internal_catch ()
> #12 0x000055e30362a374 in command_loop ()
> #13 0x000055e30362d1c3 in recursive_edit_1 ()
> #14 0x000055e30362d418 in Frecursive_edit ()
> #15 0x000055e30356b311 in main ()
> [Inferior 1 (process 174496) detached]

AFAIU, this backtrace just says that Emacs waits for some input, so it
isn't very informative.  The question is why it doesn't _get_ any
input?