Comment by zahlman
16 hours ago
> Unless memory mapped by the OS with no impact on runtime for unused parts?
Yeah, this is presumably why a no-op `uv` invocation on my system takes ~50 ms the first time and ~10 ms each other time.
> Exactly, so again have no impact?
Only if your invocation of pip manages to avoid an Internet request. Note: pip will make an Internet request if you try to install a package by symbolic name even if it already has the version it wants in cache, because its cache is an HTTP cache rather than a proper download cache.
But even then, there will be hundreds of imports mainly related to Rich and its dependencies.
> Only if your invocation of pip manages to avoid an Internet request.
Yes it does, by definition, the topic of discussion is the impact of unused code paths? How is http cache relevant here? That's a used path!
I got confused by the direction of the discussion.
My original point was that Requests imports in pip used to not be deferred like that, so you would pay for them up front, even if they turned out to be irrelevant. (But also they are relevant more often than they should be, i.e. the deferral system doesn't work as well as it should.)
Part of the reason you pay for them is to run top-level code (to create function and class objects) that are irrelevant to what the program is actually doing. But another big part is the cost of actually locating the files, reading them, and deserializing bytecode from them. This happens at import time even if you don't invoke any of the functionality.