Licensing issue with Stackoverflow's CC-BY-SA License

[uptickmetachu]

Hi, thank you for this amazing tool!

We have recently been FOSS audited and this package was flagged with potential licensing issues.

Code copied/distributed and/or adapted from Stackoverflow requires:

1. attribution and
2. licensing under the same license as the original (CCA-BY-SA-3.0 or CCA-BY-SA-4.0).
   This repositories BSD-3 License is not compatible with CCA-BY-SA.

The code that is causing issue:

ipython/IPython/utils/text.py

Line 408 in a2c2a2d

def long_substr(data):

Consider changing the implementation of the function such that the attribution isn't required.

[Carreau]

2. licensing under the same license as the original (CCA-BY-SA-3.0 or CCA-BY-SA-4.0).

Original post if pre 2011 so will be CC-BY-SA-2.5 (also you have extra A in CCA).
The effect is still the same though IIUC.

[MrMino]

TBH I don't find this code necessary. If I understand it correctly, the part required is finding the common prefix, not the common substring, so this is unnecessarily quadratical.

I'll refactor it and post a PR today.

[Carreau]

Actually this is used in only one place, and to find the longest common prefix that only contain whitespace and >. So it can be replaced by something much faster and simpler.

[Carreau]

Ha, simultaneous comments :-)

[uptickmetachu]

Thank you for your quick replies! Sorry about the typo in the original post.

[MrMino]

Fixed in #13041.

[MrMino]

@uptickmetachu FYI 7.26 which fixed this issue has been released today.