As noted in https://bugs.gnu.org/9089
ksh gives intermittent ECONNRESET errors with closed pipes.
This can be seen reliably on Linux with:
ksh -c 'yes | (sleep .1; head -n10 >/dev/null)'
* tests/misc/io-errors.sh: Avoid part of test on ksh.
* tests/misc/write-errors.sh: Likewise.
This patch also fixes a bug where 'tac' would print a vague error on
some inputs:
$ seq 10000 | ./src/tac-prev > /dev/full
tac-prev: write error
$ seq 10000 | ./src/tac > /dev/full
tac: write error: No space left on device
In this case ferror (stdout) is true, but errno has been set back to
zero by a successful fclose (stdout) call.
* src/tac.c (output): Call write_error() if fwrite fails.
* tests/misc/io-errors.sh: Check that 'tac' prints a detailed write
error.
* NEWS: Mention the improvement.
* tests/misc/io-errors.sh: Support checkout for a specific error
in commands that don't run indefinitely. Currently all the explicitly
listed commands output a specific error and do not need to be tagged.
* NEWS: Mention the improvement.
* src/id.c (print_stuff): Call fflush for each listed user to check for
write errors.
* tests/misc/io-errors.sh: Add an invocation of 'id'.
* NEWS: Mention the improvement.
* src/groups.c (main): Call fflush for each listed user to check for
write errors.
* tests/misc/io-errors.sh: Add an invocation of 'groups'.
* tests/misc/io-errors.sh: Verify that all commands diagnose write
errors, and handle a closed pipe appropriately.
* tests/local.mk: Reference the new test.
