pyasn1/coded/ber: Fix regressions dealing with component == None

[noelpower]

since commit 4f644c5

#!/usr/bin/env python3
import sys, os.path, io, string
import base64

from pyasn1.codec.der.decoder import decode as pyasn1_der_decode

def main ():
blob = "fk8wTaADAgEFoQMCAR6kERgPMjAyMzA2MDYxMDAxMTlapQU"
"CAwIstqYDAgEsqRUbEzx1bnNwZWNpZmllZCByZWFsbT6qCzAJoAMCAQChAjAA"
obj, _ = pyasn1_der_decode(base64.b64decode(blob))
if name == 'main':
main()

results in

File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 2003, in call
for asn1Object in streamingDecoder:
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 1918, in iter
for asn1Object in self._singleItemDecoder(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 1778, in call
for value in concreteDecoder.valueDecoder(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 99, in valueDecoder
for value in decodeFun(substrate, asn1Spec, tagSet, length, **options):
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 1778, in call
for value in concreteDecoder.valueDecoder(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 660, in valueDecoder
for asn1Object in self._decodeComponentsSchemaless(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 596, in _decodeComponentsSchemaless
for component in decodeFun(substrate, **options):
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 1778, in call
for value in concreteDecoder.valueDecoder(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 99, in valueDecoder
for value in decodeFun(substrate, asn1Spec, tagSet, length, **options):
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 1778, in call
for value in concreteDecoder.valueDecoder(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 660, in valueDecoder
for asn1Object in self._decodeComponentsSchemaless(
File "/home/tux/pyasn1/pyasn1/codec/ber/decoder.py", line 604, in _decodeComponentsSchemaless
componentTypes.add(component.tagSet)
AttributeError: 'NoneType' object has no attribute 'tagSet'

This change restores the previous code that will avoid this error.

also see

snippet mentioned in test code above should decode
see https://lapo.it/asn1js/#fk8wTaADAgEFoQMCAR6kERgPMjAyMzA2MDYxMDAxMTlapQUCAwIstqYDAgEsqRUbEzx1bnNwZWNpZmllZCByZWFsbT6qCzAJoAMCAQChAjAA

[noelpower]

failing check doesn't seem to be related to change :/ not sure what the procedure is here (and don't see a way to restart the test)

[Avasam]

@noelpower Closing and re-opening a PR will cause GitHub to retrigger the checks with updated workflow.

[bor8]

Short:

Bump/LGTM

Long:

This PR addresses a potential "AttributeError: 'NoneType' object has no attribute 'tagSet'" during schema-less ASN.1 object decoding by refining the _decodeComponentsSchemaless method. It ensures asn1Object is properly initialized before accessing its tagSet, preventing errors when a component is None. Additionally, it improves type guessing for ASN.1 containers based on component diversity, enhancing overall decoding reliability.

Tested across various scenarios, these changes significantly bolster decoding accuracy without introducing new issues. I recommend this merge to improve our project's robustness and decoding functionality.

Thanks for considering this fix.

[noelpower]

@noelpower Closing and re-opening a PR will cause GitHub to retrigger the checks with updated workflow.

gah had forgotten about this, I think I must have missed this (and only saw it with notification of a recent comment)