For debugging, accessing private innards is fine because the version doesn't change before you're done. For long-lasting features, you can perform a risk-based

For debugging, accessing private innards is fine because the version doesn't change before you're done. For long-lasting features, you can perform a risk-based analysis as to the likely stability of the implementation details you're accessing. But as a general rule: as a library author I deeply resent people who cause ME to get blamed when I change an implementation detail and their fragile code breaks when my library gets upgraded. https://xkcd.com/1172/ https://xkcd.com/1172/ > This update broke my workflow! My control key is hard to reach, so I hold spacebar instead, and I configured Emacs to interpret a rapid temperature rise as "control".