Singles: Working level step toward unaffected_versions field automation in support of #649

[jasnow]

Singles: Working level step toward unaffected_versions: field automation in support of #649.

• Mostly used code from patched_versions automation.
• Now output: based on vulnerableVersionRange input.
• Now connected with the patched_versions values.
• See TODO:'s for remaining known work.

"Singles" means a [single line, single range] for GHSA vulnerableVersionRange input.
See #949 for draft roadmap.

[jasnow]

Ready for merge. Check out Roadmap in #649 for more details.

[postmodern]

After looking over the algorithm, four things I'd like to do:

1. Generate the correct unaffected_versions, instead of generating pseudo-data which is then meant to be edited.
2. Simplify the logic. I think all we have to do is check if the first vulnerableVersionRange starts with <= vs. >/>=. If the first vulnerableVersionRange starts with > or >=, that means all versions below that version range are not vulnerable, thus unaffected. You could then derive the unaffected version range from the first vulnerableVersionRange by "inverting" the version range operator (ex: > X.Y.Z -> <= X.Y.Z, >= X.Y.Z -> < X.Y.Z).
3. Avoid using abbreviated method/variable names for readability. fpv or vers can be confusing to someone who's reading the code for the first time and hasn't yet learned the terminology.
4. Remove debugging puts statements and commented out code.

[jasnow]

After looking over the algorithm, four things I'd like to do:

1. Generate the correct unaffected_versions, instead of generating pseudo-data which is then meant to be edited.
2. Simplify the logic. I think all we have to do is check if the first vulnerableVersionRange starts with <= vs. >/>=. If the first vulnerableVersionRange starts with > or >=, that means all versions below that version range are not vulnerable, thus unaffected. You could then derive the unaffected version range from the first vulnerableVersionRange by "inverting" the version range operator (ex: > X.Y.Z -> <= X.Y.Z, >= X.Y.Z -> < X.Y.Z).
3. Avoid using abbreviated method/variable names for readability. fpv or vers can be confusing to someone who's reading the code for the first time and hasn't yet learned the terminology.
4. Remove debugging puts statements and commented out code.

Your way of solving this problem will be better.