Strange put-char encoding-error "conversion to port encoding failed"

Hey,

I've been seeing some strange occasional errors for a while now.

Here are some log messages from the guix-build-coordinator:

worker-thread: exception: (encoding-error put-char conversion to port encoding failed 84 #<output: file 1> s)

encoding-error (put-char conversion to port encoding failed 84 #<output: file 1> s)

encoding-error (put-char conversion to port encoding failed 84 #<output: file 1> w)

encoding-error (put-char conversion to port encoding failed

84 #<output: file 1> 2

encoding-error (put-char conversion to port encoding fencoding-error (put-char conversion to port encoding failed 84 #<o

utput: file 1> w)

encoding-error (put-char conversion to port encoding failed 84 #<output: file 1> w)

2022-10-02 17:23:38 (ERROR): error running build-success hook: encoding-error (put-char conversion to port encoding failed

84 #<output: file 1> B)

Throw to key `encoding-error' with args `("put-char" "conversion to port encoding failed" 84 #<output: file 1> #\p)'.

2022-10-02 21:21:37 (ERROR): error running build-success hook: misc-error (#f ~A (error: command failed (1): (/gnu/store/6

Throw to key `encoding-error' with args `("put-char" "conversion to port encoding failed" 84 #<output: file 1> #\space)'.

Throw to key `encoding-error' with args `("put-char" "conversion to port encoding failed" 84 #<output:

file 1> #\2)'.

I'm not sure what the 84 means? If I'm picking out the characters that

have failed to be encoded, I'm not sure why some of these would fail

(like space or w)?

Unfortunately I'm not sure how to reproduce this. Suspendable ports

might be a factor here as that is probably in use.

Hi,

Could the error be due to the 7-bit encoding in HTTP headers? [1] The

"84" is EILSEQ from errno.h. [2] Wingo added the functionality here. [3]

I also submitted a patch to resolve in the errno. [4]

A similar issue appeared in Guix's Cuirass. [5]

Kind regards

Felix

[1] https://lists.gnu.org/archive/html/guile-user/2020-09/msg00015.html

[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/asm-generic/errno.h#n67

[3] https://git.savannah.gnu.org/cgit/guile.git/commit/?id=43b6feeb1adafe54170304e7cc3c29a15c1d3808

[4] https://debbugs.gnu.org/68624

[5] https://debbugs.gnu.org/59510