Do not map (leave as is) trailing / or \ in github URLs.

[yarikoptic]

Otherwise we would fail to clone (git would start asking for password since there is no such repo) github repositories while including trailing / which should be perfectly fine and which git handles just fine:

❯ datalad -l debug clone https://github.com/datasets-mila/datasets--robotcar/
[DEBUG  ] Command line args 1st pass for DataLad 0.18.4+21.g560dc910e. Parsed: Namespace() Unparsed: ['clone', 'https://github.com/datasets-mila/datasets--robotcar/']
[DEBUG  ] Building doc for <class 'datalad.core.distributed.clone.Clone'>
[DEBUG  ] Parsing known args among ['/home/yoh/proj/datalad/datalad-maint/venvs/dev3/bin/datalad', '-l', 'debug', 'clone', 'https://github.com/datasets-mila/datasets--robotcar/']
[DEBUG  ] Determined class of decorated function: <class 'datalad.core.distributed.clone.Clone'>
[DEBUG  ] Determined clone target path from source
[DEBUG  ] Resolved clone target path to: '/tmp/datasets--robotcar'
[DEBUG  ] Apply ephemeral patch to clone.py:_pre_annex_init_processing_
[DEBUG  ] Apply ephemeral patch to clone.py:_post_annex_init_processing_
[DEBUG  ] Apply RIA patch to clone.py:_post_git_init_processing_
[DEBUG  ] Apply RIA patch to clone.py:_pre_final_processing_
[DEBUG  ] URL substitution: 'https://github.com/datasets-mila/datasets--robotcar/' -> 'https://github.com/datasets-mila/datasets--robotcar-'
[DEBUG  ] Git clone from https://github.com/datasets-mila/datasets--robotcar- to /tmp/datasets--robotcar
[DEBUG  ] Run ['git', '-c', 'diff.ignoreSubmodules=none', 'clone', '--progress', 'https://github.com/datasets-mila/datasets--robotcar-', '/tmp/datasets--robotcar'] (protocol_class=GitProgress) (cwd=None)
[DEBUG  ] Non-progress stderr: b"Cloning into '/tmp/datasets--robotcar'...\n"
Cloning:  50%|███████████████████████████████████████████████                                               | 1.00/2.00 [00:00<00:00, 534 candidates/s]Username for 'https://github.com':

The fix consists of adding negative lookahead that the final (back)slash is not at the end of the string. I was not sure why (how do we get one) we are to map any backslash so did not introduce any special handling for it, so it just follows the same rule -- the last one would not be mapped.

[mih]

Makes sense. Thx for the detailed commit message, much appreciated!

[yarikoptic]

appveyour on mac unrelated afaik

FAILED ../datalad/core/distributed/tests/test_push.py::test_ria_push - datalad.runner.exception.CommandError: CommandError: 'git -c diff.ignoreSubmodules=none annex findref --anything HEAD --json --json-error-messages -c annex.dotfiles=true' failed with exitcode 139 under /Users/appveyor/DLTMP/datalad_temp_test_ria_pushl12zigr9 [info keys: stdout_json] [err: 'error: git-annex died of signal 11']

[yarikoptic-gitmate]

PR released in 0.18.5