* shuf: fix panic/abort on large -i range without small --head-count
NonrepeatingIterator::new sized its sparse hash map to
min(head_count, range_len) and allocated it with the infallible
with_capacity_and_hasher. head_count defaults to u64::MAX when -n is
absent (and can be passed a huge value explicitly), so for a large -i
range the map was asked to reserve the whole range:
shuf -i 1-9999999999999999999 # no -n
shuf -i 1-9999999999999999999 -n 9999999999999999999
Both aborted (exit 134) with a hashbrown "Hash table capacity overflow"
panic or an allocator abort, where GNU prints "memory exhausted" and
exits 1.
Reserve fallibly with try_reserve (mirroring the Vec branch) and map
the failure to a clean error, so an unsatisfiable request errors like
GNU instead of crashing. A small --head-count still works unchanged.
Closes#12500.
* shuf: assert full stderr (incl. program prefix) in memory-exhausted tests
Per review on #12501: switch the two memory-exhausted regression tests
from stderr_contains to stderr_only("shuf: memory exhausted\n") so they
verify the whole stderr, including the `shuf:` program-name prefix.
Daniel Hofstetter
oech3
Nikola Lukovic
Sylvestre Ledru
oech3
Wei Li
Lorenzo Rossi