unhandled EAGAIN from NodeJS' writeSync

[PAStheLoD]

Hello!

I've run into a strange problem with the following code (which worked perfectly for ~2 weeks as part of a CI script, now and today suddenly after ~800 lines of output), one of the pipes was not able to keep up and Node's writeSync threw an EAGAIN.

await $`docker compose build ${service}`
      .env({ COMPOSE_BAKE: "true" })
      .stdout("inheritPiped")
      .stderr("inheritPiped")
      .captureCombined();

node:fs:912
  handleErrorFromBinding(ctx);
  ^
Error: EAGAIN: resource temporarily unavailable, write
    at writeSync (node:fs:912:3)
    at Object.writeSync (file:///opt/node_modules/.pnpm/@deno+shim-deno@0.19.2/node_modules/@deno/shim-deno/dist/index.mjs:642:12)
    at CapturingBufferWriterSync.writeSync (file:///opt/node_modules/.pnpm/dax@0.45.0/node_modules/dax/esm/mod.js:6727:40)
    at CapturingBufferWriterSync.writeSync (file:///opt/node_modules/.pnpm/dax@0.45.0/node_modules/dax/esm/mod.js:6727:40)
    at writeAllSync2 (file:///opt/node_modules/.pnpm/dax@0.45.0/node_modules/dax/esm/mod.js:3506:24)
    at ShellPipeWriter.writeAll (file:///opt/node_modules/.pnpm/dax@0.45.0/node_modules/dax/esm/mod.js:6690:14)
    at pipeReadableToWriterSync (file:///opt/node_modules/.pnpm/dax@0.45.0/node_modules/dax/esm/mod.js:6863:33)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async readStdOutOrErr (file:///opt/node_modules/.pnpm/dax@0.45.0/node_modules/dax/esm/mod.js:7010:3)
    at async Promise.all (index 1) {
  errno: -11,
  syscall: 'write',
  code: 'EAGAIN'
}
Node.js v25.8.0

CapturingBufferWriterSync.writeSync is here, where a loop might make sense. (Or maybe it should go into shim-deno. I see there's at least one EAGAIN issue there, but I have no idea what's Deno's "API contract" for writeSync, is it supposed to retry on EAGAIN automatically or not.)

Thanks for (dax and for) your time and attention!