I did a quick search to see what code would break from sys.argv[0] going relative

  intext:"sys.argv[0]" ext:py site:github.com
  https://www.google.com/search?q=intext:"sys.argv%5B0%5D"+ext:py+site:github.com

and while most uses of it are to print usage messages. There is potentially code relying on it being a relative path that will break from this change:

* https://github.com/google/python-gflags/blob/4f06c3d0d6cbe9b1fb90ee9fb1c082b3bf9285f6/gflags/flagvalues.py#L868-L869
* https://github.com/HcashOrg/hcOmniEngine/blob/f1acc2ba3640a8e1c651ddc90a86d569d00704fe/msc-cli.py#L12
* https://github.com/vmtk/vmtk/blob/64675f598e31bc6be3d4fba903fb59bf1394f492/PypeS/pyperun.py#L35
* https://github.com/apache/lucene-solr/blob/cfa49401671b5f9958d46c04120df8c7e3f358be/dev-tools/scripts/svnBranchToGit.py#L783

I think Michel and Nick are correct here and the status-quo should be maintained for sys.argv[0]. Michel should not have to enumerate the use cases for a relative sys.argv[0].