asn1Decoding(1) fails to decode a CHOICE?

[Ivan Shmakov]

        It seems like asn1Decoding(1) (as of 2.13 debian 2; though there
        don't seem to be any relevant entries in the log [1] in between
        2.13 and 2.14) fails to decode a CHOICE.  Consider, e. g.:

$ asn1Decoding \
      <(printf %s\\n \
            'Example { } DEFINITIONS EXPLICIT TAGS ::=' \
            BEGIN \
            'Foo ::= CHOICE { bar [0] INTEGER, baz [1] INTEGER }' \
            END) \
      <(printf '\x80\x01\x2a') \
      Example.Foo 
Parse: done.

Decoding: DER_ERROR
asn1Decoding: 

DECODING RESULT:
$ 

        On the contrary, Perl's Convert::ASN1 [2] decodes it just fine:

$ perl -we 'use strict;
            require Convert::ASN1;
            require Data::Dump;
            my $asn = Convert::ASN1->new ();
            $asn->prepare (q {
                Foo ::= CHOICE { bar [0] INTEGER, baz [1] INTEGER }
                }) or die ();
            foreach my $enc ("\x80\x01\x2a", "\x81\x01\x2a") {
                my $dec
                    = $asn->decode ($enc)
                    or die ($asn->error ());
                print STDOUT (Data::Dump::dump ($enc, $dec), "\n");
            }' 
("\x80\1*", { bar => 42 })
("\x81\1*", { baz => 42 })
$ 

        Also, the documentation doesn't seem to mention on how to encode
        a CHOICE with asn1Coding(1) [3], and just omitting the “unused”
        element(s) leads to a failure.

[1] http://git.savannah.gnu.org/gitweb/?p=libtasn1.git;a=shortlog
[2] http://search.cpan.org/dist/Convert-ASN1/
[3] 
http://www.gnu.org/software/libtasn1/manual/html_node/Invoking-asn1Coding.html

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