bug#31280: zgrep foo binaryfilepath says "Binary file (standard input) matches"

[Jim Avera]

Hello,

There is a bug in zgrep (gzip) 1.6 where the output from zgrep 
incorrectly says  "(standard input") instead the file path name given on 
the command line.

This happens if the input data is not actually compressed, but is binary 
data.

STEPS TO REPRODUCE:

perl -wE 'print "foobar",("\x0" x 1000)' > /tmp/testfile.dat  # make a 
binary file
zgrep foobar /tmp/testfile.dat

RESULTS:

Binary file (standard input) matches

EXPECTED RESULTS:

Binary file /tmp/testfile.dat matches