Update to Xeus 4.3.4

[agriyakhetarpal]

This retries the bump to Xeus 4.3.4, as we split it away from #298.

[agriyakhetarpal]

Unfortunately the "Switch to R kernel and run R code" test shows that it crashes, and I don't know what we can do about it. The video from the CI artifacts doesn't reveal anything substantive.

[agriyakhetarpal]

I don't think I have any insight into what's happening here, @krassowski and @peytondmurray – if you could take a look at this and offer any guidance, or perhaps take over and see if you can budge this, possibly, that would be great. Thanks!

[krassowski]

Testing it locally: it works, although it does log an ominous error in the console (memory access out of bounds):

961.95551d4646318e012932.js?v=95551d4646318e012932:1 xr contents will be synced with Jupyter Contents
647.02c9b5c75d60213c7431.js?v=02c9b5c75d60213c7431:1 Switched to kernel: xr.
xr.js:9 R is ready
78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1  Failed to load dynlib /lib/R/library/dplyr/libs/dplyr.so Error: memory access out of bounds
    at sB (http://127.0.0.1:8000/extensions/@jupyterlite/xeus-extension/static/78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1:4683384)
    at async oB (http://127.0.0.1:8000/extensions/@jupyterlite/xeus-extension/static/78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1:4682193)
    at async Promise.all (index 23)
    at async FB (http://127.0.0.1:8000/extensions/@jupyterlite/xeus-extension/static/78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1:4689470)
    at async eB.initializeInterpreter (http://127.0.0.1:8000/extensions/@jupyterlite/xeus-extension/static/78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1:4695415)
    at async eB.initialize (http://127.0.0.1:8000/extensions/@jupyterlite/xeus-extension/static/78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1:4691938)
oB @ 78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1
xr.js:9 
xr.js:9 R version 4.5.1 (2025-06-13) -- "Great Square Root"
xr.js:9 Copyright (C) 2025 The R Foundation for Statistical Computing
xr.js:9 Platform: wasm32-unknown-emscripten (32-bit)
xr.js:9 
xr.js:9 R is free software and comes with ABSOLUTELY NO WARRANTY.
xr.js:9 You are welcome to redistribute it under certain conditions.
xr.js:9 Type 'license()' or 'licence()' for distribution details.
xr.js:9 
xr.js:9 R is a collaborative project with many contributors.
xr.js:9 Type 'contributors()' for more information and
xr.js:9 'citation()' on how to cite R or R packages in publications.
xr.js:9 
xr.js:9 Type 'demo()' for some demos, 'help()' for on-line help, or
xr.js:9 'help.start()' for an HTML browser interface to help.
xr.js:9 Type 'q()' to quit R.
xr.js:9 
xr.js:9  During startup - Warning message:
put_char @ xr.js:9
write @ xr.js:9
write @ xr.js:9
doWritev @ xr.js:9
_fd_write @ xr.js:9
$func4686 @ xr.wasm:0x40b7f9
$__vfprintf_internal @ xr.wasm:0x43eb49
$vfprintf @ xr.wasm:0x43f966
$func2687 @ xr.wasm:0x29246a
$REvprintf @ xr.wasm:0x28f77b
$REprintf @ xr.wasm:0x28f74b
$func1680 @ xr.wasm:0x1cf73a
invoke_v @ xr.js:9
$setup_Rmainloop @ xr.wasm:0x242123
$Rf_initEmbeddedR @ xr.wasm:0x2fdca7
invoke_iii @ xr.js:9
$_ZN6xeus_r11interpreterC2EiPPc @ xr.wasm:0x114cb1
$_ZN6xeus_r16wasm_interpreterC1Ev @ xr.wasm:0x126bb4
invoke_ii @ xr.js:9
$func218 @ xr.wasm:0xf8603
invoke_ii @ xr.js:9
$func217 @ xr.wasm:0xf83d3
constructor xkernel @ VM41:5
xkernel @ xr.js:9
initialize @ 78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1
xr.js:9  In Sys.which("uname") : 'which' was not found on this platform
put_char @ xr.js:9
write @ xr.js:9
write @ xr.js:9
doWritev @ xr.js:9
_fd_write @ xr.js:9
$func4686 @ xr.wasm:0x40b7f9
$__vfprintf_internal @ xr.wasm:0x43eb49
$vfprintf @ xr.wasm:0x43f966
$func2687 @ xr.wasm:0x29246a
$REvprintf @ xr.wasm:0x28f77b
$REprintf @ xr.wasm:0x28f74b
$func1680 @ xr.wasm:0x1cf8d6
invoke_v @ xr.js:9
$setup_Rmainloop @ xr.wasm:0x242123
$Rf_initEmbeddedR @ xr.wasm:0x2fdca7
invoke_iii @ xr.js:9
$_ZN6xeus_r11interpreterC2EiPPc @ xr.wasm:0x114cb1
$_ZN6xeus_r16wasm_interpreterC1Ev @ xr.wasm:0x126bb4
invoke_ii @ xr.js:9
$func218 @ xr.wasm:0xf8603
invoke_ii @ xr.js:9
$func217 @ xr.wasm:0xf83d3
constructor xkernel @ VM41:5
xkernel @ xr.js:9
initialize @ 78.c18df1cd66aa8131a8a6.js?v=c18df1cd66aa8131a8a6:1

[agriyakhetarpal]

Okay, makes sense. The "memory access out of bounds" error not showing up locally but showing up in CI most likely just means that the CI runner has too less RAM. Is there something we can do to reduce the memory consumption of the tests in Playwright or free up memory in the runner?

[krassowski]

That error - I saw it locally, not on CI.

[agriyakhetarpal]

Ah, sorry, I misread!

I ran 4.3.4 locally, and it reported no memory access errors to me on a fresh tab. My machine has 18 GiB RAM, so nearly the same as yours I assume.

[krassowski]

Well, since it fails on v4.2.1 but not on v4.2.0 it must be down to jupyterlite/xeus#274. It appears to be linked in jupyterlite/xeus#281, but it does not seem related at first glance.

[krassowski]

memory access out of bounds

Does not seem to be about resource usage, but about unsafe access which is worse and can trigger crashes.