bug#11956: misc/tty-eof: sometimes failure under heavy load

[Jim Meyering]

Bernhard Voelker wrote:
> FAIL: misc/tty-eof (exit: 1)
> ============================
>
> F: 1: YSBiCg==
> F: 1: a b
> F: 1: 780509149 4
> F: 1: a b
> F: 1: a b
> F: 1: a b
> F: 1: a b
> F: 1: a b
> F: 1: 7557d2f3a6ad1a3a8ebd23a94ab0c642  -
> F: 1:      1    a b
> F: 1: 0000000 020141 005142
> F: 1: a b
> F: 1:
> F: 1:                                        a b
> F: 1: 90ce62edf2fe4940e041a68b13e7b5f9d02bbf51  -
> F: 1: afa36e61f94d23fa2869cc1ca3c7a0855ecb7f3d3305e446e7566d1f  -
> F: 1: 01186fcf04b4b447f393e552964c08c7b419c1ad7a25c342a0b631b1967d3a27  -
> F: 1:
> adf433b1ea7db8dec7ca64f88f4c8bc5403a1ac1d3540ae0229c79fc8d84e3db4dd9616605c61215ee7c50da0a97d0e2
> -
> F: 1:
> ae206702ea661de518d6451ee5b76fe0120429239b73838301991a294bc2628c0b9bbe79d06b1ab0610a66e9ce7d7e16cdcbdc244058befefc03c5d9cce54357
>  -
> F: 1: a b
> tty-eof: sort didn't produce expected output
> F: 1: 08271     1
> tty-eof: tac didn't produce expected output
> F: 1: a b
> F: 1: a b
> F: 1: a
> F: 1: a b
> F: 1: a b
> F: 1:       1       2       4
>
> I was running "make check-very-expensive -j 10 -l 4", and as misc/tty-eof
> is quite at the top, "make" maybe didn't have a chance to balance to load
> 4 yet. It happens only under heavy load (CPU and disk), but I can not
> reproduce it under "normal" conditions. However, with "-j 10 -l 4",
> I hit it quite regularly (1 out of 4 times).
>
> And sometimes, the "tac" error message is not there, only the "sort" error
> is there.
>
> Any idea what is going on?

Thanks for the report.
I'll bet that the 1-second timeout is expiring.
Does this solve it for you?

diff --git a/tests/misc/tty-eof b/tests/misc/tty-eof
index e9eed2e..28b4fa3 100755
--- a/tests/misc/tty-eof
+++ b/tests/misc/tty-eof
@@ -73,7 +73,7 @@ $@
         or $exp->send("a b\n");
       $exp->send("\cD");  # This is Control-D.  FIXME: what if that's not EOF?
       $exp->expect (0, '-re', "^a b\\r?\$");
-      my $found = $exp->expect (1, '-re', "^.+\$");
+      my $found = $exp->expect (10, '-re', "^.+\$");
       $found and warn "F: $found: " . $exp->exp_match () . "\n";
       $exp->expect(10, 'eof');
       # Expect no output from cut, since we gave it no input.