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commit 36099d0a4368321504753a389cadaa15cc1cae23
Author: Nicholas Clark <[email protected]>
Date: Fri Jul 1 09:28:20 2011 +0200
The test for #76474 should open file descriptor 0, not 1.
The original bug report states
if we try to dup STDIN in a child process by using it's file descriptor
but has code to dup 1, not 0:
perl -MIPC::Open3 -wle 'open3("<&1", my $out, undef, $^X)'
Change the above code to "<&0" and the same bug is demonstrated, and fixed
by
the relevant change.
However, trying to open descriptor 1 for input causes subtle portability
problems, which conceal the actual bug we're attempting to test. On most
platforms the terminal is read write, and a command tested on the command
line
actually has file descriptor 1 read/write (and probably file descriptor 0
also)
When the output is being piped, for example in a test checking the output,
descriptor 1 is (likely to be) write only. PerlIO is quite happy to *open* a
such a numeric file descriptor for reading, and will only generate an error
if
an actual read is attempted (which this test does not). stdio (on several
platforms tested) fails the *open* in the same scenario. Hence whether this
*test* passed or failed depended on the IO system used, which is actually
not
what we want to test.
Original test added in a0ed8b7b5f7f6d6f, fix added in fb9b5b31d8a62644.
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