fix: handle ps.tree() failure gracefully in kill() on Alpine Linux

[Luc0-0]

Problem

On Alpine Linux (and other environments using BusyBox), kill() throws an unexpected TypeError instead of killing the process:

TypeError: Cannot read properties of undefined (reading 'spaces')
    at getBorders (vendor-core.cjs)
    at parseUnixGrid (vendor-core.cjs)

This was introduced in v8.8.4 when @webpod/ps replaced the previous process tree implementation. BusyBox ps produces output in a format that @webpod/ingrid cannot parse — it returns an empty array, causing lines[0].spaces to throw.

Reported in #1369.

Fix

Wrap the ps.tree() loop in a try/catch in src/core.ts. If the process tree lookup fails (e.g. due to an unrecognised ps output format), execution falls through to the existing process.kill(pid) call below, which still terminates the target process. Child processes may not be killed in degraded environments, but the caller no longer receives an unexpected error.

// Before
for (const p of await ps.tree({ pid, recursive: true })) {
  try { process.kill(+p.pid, signal) } catch (e) {}
}

// After
try {
  for (const p of await ps.tree({ pid, recursive: true })) {
    try { process.kill(+p.pid, signal) } catch (e) {}
  }
} catch (e) {
  // ps.tree() can fail on non-standard ps implementations (e.g. BusyBox on
  // Alpine Linux). Fall through to direct process.kill() below.
}

The root cause is in @webpod/ingrid's parser — a fix there would be more complete — but this makes kill() robust against any future parser failures as well.

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[antongolub]

This is not a fix, but a workaroud. We should figure out what exactly goes wrong with BusyBox + ps.

[Luc0-0]

Traced it — getBorders() in @webpod/ingrid hits lines[0].spaces without checking for empty input. BusyBox ps doesn't support -lx so @webpod/ps gets back empty/garbage output, parseLines() returns [], and boom — TypeError on undefined.

Root fix would be a if (lines.length === 0) return [] guard in getBorders(), and maybe having @webpod/ps detect BusyBox and use ps -o pid,ppid,comm instead of ps -lx.

Kept the try/catch here so kill() doesn't throw a random TypeError when the process is perfectly killable via process.kill() directly. Updated the comment to point at the actual source. Can open PRs on ingrid/ps if you'd prefer fixing it there.

[Luc0-0]

Opened the upstream fixes btw:

• fix: guard getBorders() against empty lines input webpod/ingrid#11 — empty input guard in getBorders()
• fix: fall back to POSIX ps flags on BusyBox/Alpine webpod/ps#16 — POSIX fallback when ps -lx returns nothing

Once those land and get re-vendored, the try/catch here becomes redundant. Until then it keeps kill() from blowing up on Alpine.