[Python-Dev] Smoothing the transition from Python 2 to 3 (original) (raw)

Cody Piersall cody.piersall at gmail.com
Fri Jun 10 10:09:27 EDT 2016

One problem is that the str literals should be bytes literals. Comparison with None needs to be avoided.

With Python 2 code runs successfully. With Python 3 the code crashes with a traceback. With my modified Python 3.6, the code runs successfully but generates the following warnings: test.py:13: DeprecationWarning: encoding bytes to str output.write('%d:' % len(s)) test.py:14: DeprecationWarning: encoding bytes to str output.write(s) test.py:15: DeprecationWarning: encoding bytes to str output.write(',') test.py:5: DeprecationWarning: encoding bytes to str if c == ':': test.py:9: DeprecationWarning: encoding bytes to str size += c test.py:24: DeprecationWarning: encoding bytes to str data = data + s test.py:26: DeprecationWarning: encoding bytes to str if input.read(1) != ',': test.py:31: DeprecationWarning: default compare is depreciated if a > 0:

This seems very useful; I'm surprised that other people don't think so too. Currently, the easiest way to find bytes/str errors in a big application is by running the program, finding where it crashes, fixing that one line (or hopefully wherever the data entered the system if you can find it), and repeating the process.

This is nice because you can get in "fix my encoding errors" mode for more than just one traceback at a time; the new method would be to run the program, look at the millions of bytes/str errors, and fix everything that showed up in this round at once. That seems like a big win for productivity to me.

Cody

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