Duplicate LGPL key in rubygems LICENSES_MAPPING makes one mapping unreachable

[Daksha1611]

Description

LICENSES_MAPPING in src/packagedcode/rubygems.py defines 'LGPL' twice, on two consecutive lines (679-680):

    'LGPL': 'lgpl',
    'LGPL': 'lgpl-2.0-plus',

Both are entries of the same dict literal, so the first is discarded and every gem declaring a bare LGPL resolves to lgpl-2.0-plus.

That is worth a second look on its own: an unversioned LGPL declaration does not state a version, and lgpl-2.0-plus asserts one. The generic 'LGPL': 'lgpl' line immediately above looks like the mapping intended for the unversioned case, and the table already has separate explicit entries for the versioned spellings. Either way, which one applies is currently decided by line order rather than intent, and the unreachable line is misleading to read.

How To Reproduce

import ast, collections

src = open('src/packagedcode/rubygems.py').read()
for node in ast.walk(ast.parse(src)):
    if isinstance(node, ast.Dict):
        counts = collections.Counter(
            k.value for k in node.keys
            if isinstance(k, ast.Constant) and isinstance(k.value, str)
        )
        for key, n in counts.items():
            if n > 1:
                print(f'line {node.lineno}: duplicate key {key!r} x{n}')

line 658: duplicate key 'LGPL' x2

And the effective value:

>>> from packagedcode.rubygems import LICENSES_MAPPING
>>> LICENSES_MAPPING['LGPL']
'lgpl-2.0-plus'

The 'lgpl' entry is unreachable.

Suggested fix

Remove one of the two lines. I have opened a PR that drops the unreachable one and keeps the current result, so nothing changes at runtime. If a bare LGPL should instead stay unversioned as lgpl, that is a one-word change on top and I am happy to make it.

System configuration

• What OS are you running on? Linux (x86_64)
• What version of scancode-toolkit was used? 33.0.0rc1, develop at 5ebebf2
• What installation method was used to install/run scancode? source checkout
• Python version: 3.x