Implement split_edges

[jeromekelleher]

Closes #2276

Taking over part of #2240

[codecov]

Codecov Report

Merging #2296 (6d12abb) into main (76b6581) will decrease coverage by 0.00%.
The diff coverage is 88.79%.

@@            Coverage Diff             @@
##             main    #2296      +/-   ##
==========================================
- Coverage   93.33%   93.32%   -0.01%     
==========================================
  Files          27       27              
  Lines       26141    26256     +115     
  Branches     1175     1177       +2     
==========================================
+ Hits        24398    24503     +105     
- Misses       1713     1723      +10     
  Partials       30       30              

Flag	Coverage Δ
c-tests	92.29% <85.50%> (-0.02%)	⬇️
lwt-tests	89.05% <ø> (ø)
python-c-tests	71.87% <70.21%> (-0.01%)	⬇️
python-tests	98.88% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
c/tskit/trees.c	95.02% <85.50%> (-0.22%)	⬇️
python/_tskitmodule.c	90.90% <91.42%> (+<0.01%)	⬆️
python/tskit/trees.py	98.06% <100.00%> (+0.01%)	⬆️
c/tskit/tables.c	90.33% <0.00%> (+0.04%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 76b6581...6d12abb. Read the comment docs.

[petrelharp]

Looks very well tested! All good.

[benjeffery]

Wow, nice stuff.
Just a couple of comments:

• It might be good to test what happens when split is called with t=unknown_time?
• I can't see where the provenance info mentioned in the docstring is recorded?

[benjeffery]

Does this pattern here imply we should have a way to pass in encoded metadata to add_row? Maybe encoded_metadata=?

[jeromekelleher]

I think so - either that or have a boolean flag for controlling whether we encode or not?

[jeromekelleher]

Thanks for the careful review @benjeffery, super helpful.

I think the simplest thing is to error with nonfinite time, and have added tests.

I can't be bothered with adding provenance, it feels like a waste of effort. It's easy enough to add later if we need it.