Codeigniter 3.0 forced uppercase naming of controllers and classes

To be fair, I wasn't the one who did the change, but I don't see a big deal either way. A major revision is a time for potential BC breaks, and it was listed in the upgrade steps rather prominently.

I think in general developers should be free to decide if a file has to be mixed case or lowercase.

Then you haven't been keeping up with the PHP community in general. Both of the autoloading PSR's require a file name to match the casing of the class name, which is forced by the other PSRs to be CamelCase. So, this isn't a unique thing to CI, and most of the other frameworks out there will force your hand in the same way.

I'm sure an experienced developer knows the difference and expects a framework to behave the same in both windows and unix... it's bad if CI accept lowercase files on Windows and rejects them on Unix (without any kind of informational message btw)

CI cannot make the operating system behave differently than it does, so it's not CI that's "allowing" lowercase names in Windows (or Mac for that matter) it's the OS. Linux, however, IS case-sensitive. And there's nothing any framework can do to change that.

While it's understandable to be frustrated, learning the differences between OSs, servers, etc, is all part of our wonderful journey from new developer to an experienced developer, unfortunately.

Support Development •  CodeIgniter 4 Foundations • Practical CodeIgniter 3  • CodeIgniter Tutorials