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PyParsing 2.3.0 issue

Latest working version of PyParsing for PySZN was version 2.2.2. Then, the next release, 2.3.0, released 9 days ago, breaks the parsing of SZN.

The issue is located at line 188 of the file parser.py:

            parsed = statement.parseString(line)

With PyParsing 2.2.2 the output is the following:

ipdb> parsed
(
    ['hs1', ':', '1', '--', 'sw1', ':', '1'],
    {
        'endpoint_a': [
            ((['hs1', ':', '1'], {'node': [('hs1', 0)], 'port': [('1', 2)]}), 0),
        ],
        'endpoint_b': [
            ((['sw1', ':', '1'], {'node': [('sw1', 0)], 'port': [('1', 2)]}), 4),
        ],
        'link': [
            (
                (
                    ['hs1', ':', '1', '--', 'sw1', ':', '1'],
                    {
                        'endpoint_a': [
                            (
                                (
                                    ['hs1', ':', '1'],
                                    {'node': [('hs1', 0)], 'port': [('1', 2)]},
                                ),
                                0,
                            ),
                        ],
                        'endpoint_b': [
                            (
                                (
                                    ['sw1', ':', '1'],
                                    {'node': [('sw1', 0)], 'port': [('1', 2)]},
                                ),
                                4,
                            ),
                        ],
                        'node': [('hs1', 0), ('sw1', 4)],
                        'port': [('1', 2), ('1', 6)],
                    },
                ),
                0,
            ),
        ],
        'node': [('hs1', 0), ('sw1', 4)],
        'port': [('1', 2), ('1', 6)],
    },
)

With PyParsing 2.3.0, the following is returned:

ipdb> parsed
(
    ['hs1', ':', '1', '--', 'sw1', ':', '1'],
    {
        'endpoint_a': [(['hs1', ':', '1'], {})],
        'endpoint_b': [(['sw1', ':', '1'], {})],
        'link': [(['hs1', ':', '1', '--', 'sw1', ':', '1'], {})],
        'node': ['hs1', 'sw1'],
        'port': ['1', '1'],
    },
)

This makes that the later calls parsed.link.endpoint_a.node fail because the element doesn't exists. Because of the broad way the try/catch is set, this result in an really unrelated ParseException , but it is really not.

The solution is to review why the parser is returning such different and wrong data, as the semantics of the grammar isn't respected in the newer version.

I checked the release notes, but nothing really enlightening is said:

https://github.com/pyparsing/pyparsing/releases/tag/pyparsing_2.3.0

What is not a solution is to pin the pyparsing package in a public library, that will impose on the version users of this library may have and break their system. If you need a specific version in your environment pin it there, either before or after the pyszn requirement itself.

I started some work on the refresh branch, and still investigating the issue in depth.

Regards

hpenetworking / pyszn Goto Github PK

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