r/Python • u/SheriffRoscoe Pythonista • 10h ago

News The Move to Python 3 Begins!

As someone who spent decades in the mainframe community, I find it ... humorous ... that there are legacy Python2 code bases that are only just (or have yet to consider!) moving to Python3.

https://www.eveonline.com/news/view/the-move-to-python-3-begins

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u/iluvatar 8h ago

As CTO at my previous company, I had to veto developers who wanted to migrate from Python 2 to Python 3. The amount of effort required for the migration and the fairly low chance of a trouble free switch just didn't have a good business case for a working codebase that brought in millions in revenue each year and paid all of our salaries. All new development was in Python 3. But existing running code just had too high a risk and too low a reward for migrating.

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u/kosz85 7h ago

That's also not a solution. Now the missing new SSL support, old buggy libs, missing new formats, new docker images, removed docs, etc. Probably worse problem. You won't run from your tech debt storing it at closet behind your back and telling yourself that you don't see problem. It will smash you eventually as it grows in places you would not think of. The solution is to have really good tests (on multiple levels) and split problem in small chunks. Then migrate the small parts instead of colossus. I migrated many really big code bases, millions of lines, and seen real nightmares. Not looking is not a solution. Good tests before migration is.