Christian Couder <christian.cou...@gmail.com> writes:

> To make it possible in a following commit to move packet
> reading and writing functions into a Packet.pm module,
> let's refactor these functions, so they don't handle
> printing debug output and exiting.
>
> Signed-off-by: Christian Couder <chrisc...@tuxfamily.org>
> ---
>  t/t0021/rot13-filter.pl | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/t/t0021/rot13-filter.pl b/t/t0021/rot13-filter.pl
> index ad685d92f8..e4495a52f3 100644
> --- a/t/t0021/rot13-filter.pl
> +++ b/t/t0021/rot13-filter.pl
> @@ -60,8 +60,7 @@ sub packet_bin_read {
>       my $bytes_read = read STDIN, $buffer, 4;
>       if ( $bytes_read == 0 ) {
>               # EOF - Git stopped talking to us!
> -             print $debug "STOP\n";
> -             exit();
> +             return ( -1, "" );
>       }
>       elsif ( $bytes_read != 4 ) {
>               die "invalid packet: '$buffer'";
> @@ -85,7 +84,7 @@ sub packet_bin_read {
>  
>  sub packet_txt_read {
>       my ( $res, $buf ) = packet_bin_read();
> -     unless ( $buf eq '' or $buf =~ s/\n$// ) {
> +     unless ( $res == -1 or $buf eq '' or $buf =~ s/\n$// ) {
>               die "A non-binary line MUST be terminated by an LF.";
>       }
>       return ( $res, $buf );
> @@ -131,7 +130,12 @@ print $debug "init handshake complete\n";
>  $debug->flush();
>  
>  while (1) {
> -     my ( $command ) = packet_txt_read() =~ /^command=(.+)$/;
> +     my ( $res, $command ) = packet_txt_read();
> +     if ( $res == -1 ) {
> +             print $debug "STOP\n";
> +             exit();
> +     }
> +     $command =~ s/^command=//;
>       print $debug "IN: $command";
>       $debug->flush();

This was not an issue in the old code which died upon unexpected EOF
inside the lowest-level helper packet_bin_read(), but now you have
one call to packet_bin_read() and many calls to packet_txt_read()
whose return value is not checked for this new condition you are
allowing packet_bin_read() to return.  This step taken alone is a
regression---let's see how the remainder of the series updates the
callers to compensate.

I initially thought that it may be more Perl-ish to return undef or
string instead of returning a 2-element list, but this code needs to
distinguish three conditions (i.e. a normal string that is 0 or more
bytes long, a flush, and an EOF), so that is not sufficient.  Perl
experts on the list still may be able to suggest a better way than
the current one to do so, but that is outside the scope of this
refactoring.

Thanks for starting to work on this.

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