How is it a failure? When they were talking about Python 3 at PyCon 2008 and 2009, it was expected that the migration would take this long. Folks knew migrating would be long and hard, and that the approach would need to be revised.
It's only relatively recently that Python 3 passed a certain threshold that made deprecation of Python 2 something that could actually be executed upon. Had the growth been slower in the last five years I think the timeline would have been different.
If I was going to critique Python "failures" I think the bigger target for me would be the integration of async concepts into the platform and language. This could have been handled more smoothly and with better community cohesion, but most HNers only have a superficial understanding, i.e the GIL is bad and Python can't compete with Go.
The migration succeeded but the original plan didn't. People were supposed to write Python 2 and generate Python 3.[1] What worked was making it possible to have a single code base.
Agreed, all successful migrations I've seen started early and consistently used `from __future__` and python-future to write compatible code over a few years. This incremental approach almost made it trivial.
The original timeline was very much a guess. By the time that people got into the details in 2010-2014, it was clearer it would take much longer. This doesn't make it failure unless you lost a bet with someone on the timeline.
It's only relatively recently that Python 3 passed a certain threshold that made deprecation of Python 2 something that could actually be executed upon. Had the growth been slower in the last five years I think the timeline would have been different.
If I was going to critique Python "failures" I think the bigger target for me would be the integration of async concepts into the platform and language. This could have been handled more smoothly and with better community cohesion, but most HNers only have a superficial understanding, i.e the GIL is bad and Python can't compete with Go.