tail Obsolete -0 Crashes

[sylvestre]

Component

tail

Description

uutils accepts obsolete tail -0 FILE (NUM=0) and later hits an internal assertion in the “read backwards” path, causing a panic/crash; GNU treats -0 as “print nothing” and exits normally.

Test / Reproduction Steps

seq 1 10000 > file.txt
./target/release/coreutils tail -0 file.txt

• GNU: prints nothing.
• uutils:
  thread 'main' (2925945) panicked at src/uu/tail/src/tail.rs:393:17:
  assertion left == right failed
  left: 1
  right: 0
  note: run with RUST_BACKTRACE=1 environment variable to display a backtrace

Impact

Reliable local DoS (crash) and GNU-incompatible behavior triggered by obsolete -NUM syntax with NUM=0.

[dhr412]

Hi, @sylvestre could I be assigned this issue if that's okay? I'll follow the contribution guidelines and reach out in this thread if I have questions.

[anastygnome]

@dhr412 seems someone got it first :(

[sylvestre]

it is this pr:
#10209