Let me preface this rant by saying that I've been happily using JetBrains PyCharm for a few months, and it's certainly one of the best Python IDEs out there. The price is ridiculously low and if you're serious about Python, buying PyCharm is one of the best investments you can make. It can be used for free for 30 days, so you really should give it a shot.
This said, if you happen to work with Jython 2.2, you'll probably want to use something else. The claim that Jython is fully supported as a runtime, while literally true,
Let's say you work on Windows, and you have your Jython installed under C:\jython-2.2 (yes, it's damn old, but it's still the most widely-deployed release out there -- just ask IBM and Oracle).
You create a new project in PyCharm, then go to Settings -> Python interpreter, remove the preconfigured CPython runtime, then click on Add and point to your
Still, PyCharm should be smart enough to parse arbitrary .py files in specific directories, right? So let's click on Add... to point to
Now let's create a .py file, "from pprint import pprint", the module is recognised; "Run" the script, output is correct, life is good: Jython is indeed supported as a Python runtime.
Ok, let's do some file I/O, "import os"... uh, os is not recognised as a valid module. Same for sys. Apparently, they are somewhat special in Jython and are implemented directly into the main jar, so PyCharm can't see them for autocompletion or any other smart feature. I don't know what else is "special" in Jython 2.2, but I'd rather not have to find out.
Which brings us to the main shortcoming of PyCharm as a Jython IDE: it simply won't recognise or parse any Java jar. This is somewhat surprising, considering how the program is basically a spin-off of IntelliJ IDEA, a Java IDE, and is completely built on Java. In fact, it shares the codebase with the Python Plugin for IDEA. One would think PyCharm would be ideally suited to the task of handling the "Python on Java" mesh that is Jython, but alas that's not the case. A quick search on the IntelliJ forum brings up recent posts stating that full Jython support for autocompletion is simply not on the cards; Jython is supported as a runtime and nothing more. In fact, the Python plugin for IDEA
This state of things is a bit saddening. I don't know if this is a way for JetBrains to avoid cannibalizing its main cash-cow (IDEA), or simply a commercial oversight; the fact is that we have a product, ideally positioned to completely own a niche, which simply refuses to do so and actually delivers a second-rate experience. I hope JetBrains will re-evaluate their stance at some point, because it's a bit of a shame really.