[ekimekim]

If you're needing to think carefully on what code you call might cause a switch and what won't, you're already doing it wrong. Instead of treating gevent like coroutines with less predictable ordering, treat it like threads with more predictable ordering. You know that basic operations (eg. checking if something is a certain value, or assigning a variable) won't cause a switch. So you can do two of those in a row, without thinking about race conditions. Anything beyond that...use a lock (or a queue, or any of the other provided concurrency primitives).

[thristian]

Well, thanks to operator overloading, comparisons or assigning a variable (to a property of an object) can cause a switch. If you really need to get a mental model of what your code is doing, or could do under sufficiently unusual circumstances, gevent doesn't really provide any guarantees beyond raw threading.

Glyph (of Twisted fame) wrote a good blog-post about it: https://glyph.twistedmatrix.com/2014/02/unyielding.html