No diff shown if cell content deleted and column renamed

[Godsmith]

a.csv

a,b,c
1,2,this is not visible

b.csv

a,b,d
1,2,

Expected: "this is not visible" is shown
Actual:

[paulfitz]

Oh interesting. There's something buggy there all right. The diff isn't super wrong - you can indeed get from a.csv to b.csv by deleting column c and adding column d without any content - but it smells bad. You can force a better diff with daff --all a.csv b.csv but that won't help for real tables. Thanks for reporting the problem @Godsmith.