sort: piping stdout to `head -n 0` gives 'Broken pipe'

[BAMF0]

(Forwarded from Launchpad Bug #2133156)

Summary

When sort's output is passed to a pipe that is closed mid-write (as head -n 0 does), the error write failed: 'standard output': Broken pipe is generated.

Reproduce

1. Pipe the output of a sort invocation to head -n 0.

echo 1 | sort | head -n 0

Output:

sort: write failed: 'standard output': Broken pipe

---

2. Verify with gnusort.

echo 1 | gnusort | head -n 0

Output:

# Empty, success

System

• OS release: Ubuntu 26.04 (Development branch)
• uutils coreutils version: 0.5.0 (built from main commit: 1d6bd99)

[ChrisDryden]

Discovering in the review here: #10264 that this is actually a SIGPIPE handling issue, not a introductory uutils issue