Right now the latest PSA specification implies via an example program that if a packet experiences an error during parsing, that it will begin execution of the following control (ingress control if error occurred during ingress parser, or egress control if in egress parser).
I believe the intent was that whether your ingress or egress control examines the parser_error standard metadata field, or not, packets that experienced an error during parsing will always execute the corresponding ingress/egress control, with no automatic drop action inferred by the PSA implementation.
I can create a proposed PR for the PSA specification that makes this more explicit, and send it out for review to interested parties.
Right now the latest PSA specification implies via an example program that if a packet experiences an error during parsing, that it will begin execution of the following control (ingress control if error occurred during ingress parser, or egress control if in egress parser).
I believe the intent was that whether your ingress or egress control examines the parser_error standard metadata field, or not, packets that experienced an error during parsing will always execute the corresponding ingress/egress control, with no automatic drop action inferred by the PSA implementation.
I can create a proposed PR for the PSA specification that makes this more explicit, and send it out for review to interested parties.