PHP is a perfect example of how to undergo major transitions correctly.
In the time that it took Python to go from Python 2 to 3, PHP underwent 5.2 -> 5.3 and 5.6 -> 7.0. 5.3 changed how you write PHP in a fundamental way by introducing namespaces and PSR0 autoloading. Then, 5.6 -> 7.0 cleaned up the parser, resulting in massive speed improvements.
They did this by not breaking the universe in these major updates...or really, any of there updates. Each update would break a few specific things, warn you about a few other things that were going to break in the near future, while giving you ways to shim the old behavior if you _really_ needed it.
They also gave you ample carrots reasons to update - aside from what was already mentioned, my personal favorite update was PHP 5.4 because it introduced short array syntax, made UTF-8 the default charset, introduced traits, and finally put register globals and magic quotes out of their misery...but giving you a shim if you had some ancient project that needed it.
If you're wondering why PHP 6 was abandoned, it was because it was an update in the style of Python 3 by breaking strings everywhere. In retrospect, I think the decision to cancel 6 was the right one. Somehow, I doubt that PHP would've had the influx of data science and AI that saved Python 3.
Hats off to the project - I've long been off of the CGI-style web development narcotic, but the language put food on my table for quite some time, and the people steering the language treated their community well.
> They did this by not breaking the universe in these major updates
I don't think the amount of breakage per se was the problem with Python 3. I think the problem was that for a long time (until u"" strings in 3.3? four years after 3.0?) there was ~no way for a library to support both 2 and 3 in a single codebase. That meant that each project had to either maintain a fork, or do a "flag day" migration, which in practice meant you couldn't migrate until all your dependencies were migrated. Big mistake in retrospect.
In the time that it took Python to go from Python 2 to 3, PHP underwent 5.2 -> 5.3 and 5.6 -> 7.0. 5.3 changed how you write PHP in a fundamental way by introducing namespaces and PSR0 autoloading. Then, 5.6 -> 7.0 cleaned up the parser, resulting in massive speed improvements.
They did this by not breaking the universe in these major updates...or really, any of there updates. Each update would break a few specific things, warn you about a few other things that were going to break in the near future, while giving you ways to shim the old behavior if you _really_ needed it.
They also gave you ample carrots reasons to update - aside from what was already mentioned, my personal favorite update was PHP 5.4 because it introduced short array syntax, made UTF-8 the default charset, introduced traits, and finally put register globals and magic quotes out of their misery...but giving you a shim if you had some ancient project that needed it.
If you're wondering why PHP 6 was abandoned, it was because it was an update in the style of Python 3 by breaking strings everywhere. In retrospect, I think the decision to cancel 6 was the right one. Somehow, I doubt that PHP would've had the influx of data science and AI that saved Python 3.
Hats off to the project - I've long been off of the CGI-style web development narcotic, but the language put food on my table for quite some time, and the people steering the language treated their community well.