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0 pointsacdha6y ago0 comments

I think describing it as porting to a new language is misleading: on most of my projects, most of the work is a few minutes — run modernize/futurize, check the tests, etc. If the original developers were really sloppy about how they handle encoding, it can take longer but most of the problems I've seen have very little to do with Python rather than the fact that something still running Python 2 likely has significant technical debt issues — especially things like not having test coverage which make it a lot harder to ship changes.

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6 comments · 3 top-level

Joeboy6y ago· 2 in thread

Our product took about a year to port, from getting the go-ahead to the eventual production switch. Running modernize / futurize was like 0.01% of the work.

You're right though, we're fighting our way out of technical debt and switching to python 3 was absolutely necessary. It's forced us to sort out a lot of sketchy string / bytes handling. We do, mercifully, have ~90% test coverage.

abiogenesis6y ago

A year is astronomical. Does it involve writing tests that did not exist before?

Joeboy6y ago

I don't remember us writing any new tests specifically for the python 3 port.

One issue with the test suite was that it made heavy use of a thing called django_any that isn't supported in python 3, so decided to replace it with Factory Boy. We have about 500 django models that needed new factories. Factory Boy works quite differently and it was a lot of work to make the factories behave similarly to the old ones where possible, and update most of our ~4000 tests for the new behaviour.

So that was one issue. It was tempting to just patch django_any, but we decided to tackle the technical debt instead.

downerending6y ago· 1 in thread

> likely has significant technical debt issues

You're not wrong, but as a practical matter, that pretty much describes our entire industry.

acdhaOP6y ago

Completely agreed — I would just argue that the “Python 2 vs. 3” argument is a distraction. Java hasn't had as breaking a change but there are still a ton of places running Java 6 or 7 because they like skimping on developers more than getting security updates.

MattGaiser6y ago

> something still running Python 2 likely has significant technical debt issues

Most codebases basically.

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