[rtpg]

Another thing I appreciate about this in the Python world is it avoids an issue I've seen in node a lot, which is people being too clever by a half and pre-emptively adding major version bounds to their library. So foo depends on "bar<9", despite bar 9, 10, 11, 12, 13, and 14 all working with foo's usage of bar.

The end result of this is that you end up with some random library in your stack (4 transitive layers deep because of course it is) holding back stuff like chokadir in a huge chunk of your dep tree for... no real good reason. So you now have several copies of a huge library.

Of course new major versions might break your usage! Minor versions might as well! Patch versions too sometimes! Upper bounds pre-emptively set help mainly in one thing, and that's reducing the number of people who would help "beta-test" new major versions because they don't care enough to pin their own dependencies.