Is emacsclient --eval broken?

[Clément Pit--Claudel]

Hey emacs-dev,

I'm seeing surprising behaviour from emacsclient --eval:

    $ emacs -Q --daemon
    …
    Starting Emacs daemon.

    $ emacsclient --eval '(progn (find-file "emacsclient-input") 
(buffer-string))'
    
"\\EEEEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEEEEEE-EEEEEEEEEEEEE
 EEEEEEEEEEEEE EEE EEEEEE 
EEEEE\n\\EEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEEEEEEEEE-EEEEEEEEEEEE 
EEEEE\n\n\\EEEEEEEEEEE\\EEEEEEEEE\\EEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEEE\\EEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEE\\EEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEE\\EEEEEEEEEEEEEEE\\EEEEEEEEE\\EEEE\n\n\n\\EEEEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEE\\EEEEEEEEE\\EEEEEEEEE\n\\EEEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEE\\EEEEEEEEE\n\\EEEEEEEEEEEEEEE\\EEEEEEEEEEE\\EEEEEEEEE
 E 
EEEEE\n\n\\EEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEE\\EEEEEEEEEEEEEEE\\EEEEEEEEE\\EEEEEEE\n\\EEEEEEEEEEE\n\nEE
 EEE-EEEEEEE \\EEEEEEEEEEEEEEEEEE\nEE EEE-EEEEEEE 
\\EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEE\n\nEEEEEE
 EEEE
    *ERROR*: Unknown message: E EE EEEEE\n"

This error message isn't in emacsclient-input. Worse, it is not even 
deterministic:

    $ emacsclient --eval '(progn (find-file "emacsclient-input") 
(buffer-string))'
    
"\\EEEEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEEEEEE-EEEEEEEEEEEEE
 EEEEEEEEEEEEE EEE EEEEEE 
EEEEE\n\\EEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEEEEEEEEE-EEEEEEEEEEEE 
EEEEE\n\n\\EEEEEEEEEEE\\EEEEEEEEE\\EEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEEE\\EEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEE\\EEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEE\\EEEEEEEEEEEEEEE\\EEEEEEEEE\\EEEE\n\n\n\\EEEEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEE\\EEEEEEEEE\\EEEEEEEEE\n\\EEEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEE\\EEEEEEEEE\n\\EEEEEEEEEEEEEEE\\EEEEEEEEEEE\\EEEEEEEEE
 E 
EEEEE\n\n\\EEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEEEEEEEEEEEEEEEE\\EEEEEEEEEE\\EEEEEEEEEEEEEEE\\EEEEEEEEE\\EEEEEEE\n\\EEEEEEEEEEE\n\nEE
 EEE-EEEEEEE \\EEEEEEEEEEEEEEEEEE\nEE EEE-EEEEEEE 
\\EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEEEEEEEEE\n\n\\EEEEEEEEEEEEEEE\n\\EEEEEEEEEEEEE\n\nEEEEEE
 EEEE_EEEEE EE EEEEE\n"

(the output is still corrupted: there's no ‘_’ in the source file either).

I've attached emacsclient-input. Can someone help me figure what's going wrong? 
The error doesn't appear if I modify any of the backslashes, dashes, or 
newlines in the input...

Cheers,
Clément.

emacsclient-input
Description: Text document

signature.asc
Description: OpenPGP digital signature