Friday, November 09, 2018

PyDev 7.0 (mypy, black, pipenv, faster debugger)

PyDev 7.0 (actually, PyDev 7.0.3 after some critical bugfixes on 7.0.0) is now available.

Some of the improvements available in this version include:

Mypy may be used as an additional backend for code analysis (see the preferences in the Preferences > PyDev > Editor > Code Analysis > Mypy). It is is similar to the PyLint integration, and will run Mypy whenever a file is saved in the editor.

Black can be used as the code-formatting engine (so, it's now possible to choose between the PyDev formatter, autopep8 or Black).

pipenv may be used for managing virtual environments (so, when creating a new project, clicking to configure an interpreter not listed will present an option to create a new interpreter with pipenv).

Improvements managing interpreters: it's now possible to manage interpreters directly from the editor (so, for instance, doing ctrl+2 pip install django will use pip to install django in the interpreter related to the opened editor -- and it's possible to change pip for conda or pipenv too).

Debugger improvements

The debugger is much faster for Python 3.6 onwards (when cython compiled extensions are available).

The performance improvement on the debugger is due to the using the frame eval mode for breakpoints again.

To give some history, that mode was previously disabled on pydevd because it had some issues which made function calls much slower (even though line stepping was zero overhead), but in the end, that overhead could make the performance worse than just using the plain tracing mode. Also, it had a big memory leak and in the cases where the tracing mode had to be reenabled both modes would be active at the same time and performance would suffer quite a bit.

-- all of those should be fixed and it should now perform better or at least on par with the tracing mode with cython in all scenarios... if you like numbers, see: for some benchmarks.

p.s.: the improvements in the Debugger were sponsored by Microsoft, as the PyDev Debugger is used as the core of ptvsd, the Python debugger package used by Python in Visual Studio and the Python Extension for Visual Studio Code.


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