Previous versions of python were back-compatible. Java versions stress back-compatibility. I don't know if HN can find any counter-examples, of a language that thrived through an incompatible, code-breaking upgrade.
Python has done everything possible to avoid this fate, by maintaining 2.7. And I'm not even convinced python has gotten away with yet (e.g. kalite, offline khan academy, needs 2.7). RHEL may end up reversing this. Give it another ten years!
Amd the Enterprize is the most back-compatible thing you've ever seen. This change is going to break lots of code, and they will reverse or lose customers.
Of course. Swift 3 is one example. Ruby 1.9, as others have pointed out, is another.
PHP is yet another, and perhaps more relevant because it is close to contemperaneous. It had its "Python 3 moment" with the migration to PHP 5. Lots of BC breakages. That transition took about 3-4 years for most. Most users are now on the current major version, 7, and the remainder on 5 are mostly using its latest release (EOL is EOY). No one uses 4.
Ruby 1.9 is a great example of why you should not be too nice: they told everybody "you have a fews months, deal with it". The community moved. Python said "poor things, we understand, take those tools and years to do the thing", and the community cried, and did nothing.
PHP literally failed. They canceled V6 and jumped to V7.
The funniest part ?
None of those languages are even close to Python popularity.
Swift is not even used for most Apple codebase. Python supported even Atari.
Ruby and PHP has almost no use case outside of the web. Python is used by OS, on the web, in GIS, by data analysts, for CGI, in AI, for sysadmin, to make GUI, video games...
And Python is much, MUCH older. 1990. 4/5 years older than Ruby/PHP. It has way more technical debt to pay. Swift ? 2014
Yeah the migration was badly handled from some aspects. But honestly, given the challenge and track record of the competition, it's not too shabby.
Ruby 1.9 was working mostly the same as 1.8 while provising 2-3x speed improvment, and new exciting features.
Python 3 breaks even the basic Python 2 hello world, everything was notably slower, and not anything new and exiciting feature-wise apart ubified string support.
Given how much you like Python, I'm surprised at the gall to argue that Python had more technical debt to clean up than PHP did.
When trying to learn it, I encountered incompatible examples and tutorials, complex and changing ways to update it... and then my toy code stopped working. I eventually found the cause of the code-breaking change, fixed it... thought a bit, and decided against ruby. That's just me though.
Ruby qualifies, I'd say. From 1.8 -> 1.9 there were syntax changes, changes to how strings worked and so on. Code written for 1.8 would not in general work on 1.9 and the other way around. While it was possible (sometimes with some extra if statements) to write code that worked on both versions I would definitely call it an incompatible, code-breaking upgrade.
When Python 3 turned up and it was on average slower, my first thought was "well, good luck getting people to adopt that".
But what makes me shocked that you think that that is the case is basic basic stuff... I mean, as one obvious example, they changed the exception syntax. So, "uhhhh.... sure?" it was possible to make a program that ran on both 2 and 3, but it required using "try" with no variable assignment and then digging into Python's exception reflection support to recover the variable. And you had to do this every single time. (And of course a lot of the time the underlying core library would now throw different exceptions, making the situation all the more ludicrous.)
I had code that straddles the 1.8/1.9 boundary of Ruby, and even though I wasn't an expert at Ruby it was trivial to have code that worked for both (and I mean 100% correct: Unicode and everything; remember that neither Ruby 1.9 nor Python 3 added Unicode support, they only made Unicode support easier to obtain. for Python 2 there was already comprehensive, if non-default, support, and for Ruby 1.8 you just needed to be careful about where you did conversions).
- if you tried to support Python < 2.7.
- if you tried to support Python < 3.3
But nobody used 3.0, 1 or 2. And supporting 2.6 is like supporting ruby 1.7 and 1.8 and 1.9. Which nobody did.
And it's easy to rewrite libs when really the language started to be used in 2004.
Or maybe not, given that "gem install" still regularly crashes on anything other than the top 20 packages, so it's still not a solved issue.
Only a few like you and me tried it.
I can't recall of any big project or lib ever supporting < 3.3.
They jumped on so early the python devs were saying "WTF are you people thinking?!?"
It actually takes a fair bit of shenanigans to get hand-coded bindings into blender, my last(?) patch was bindings for the kdtree and I had to do some convincing to get that accepted. I'd guess that 99% of bpy is generated bindings.
If they stuck with python 2 when they started the initial overhaul they'd probably still be using it since artists are very vocal when their scripts break.
What? The PEP that added the new syntax also added it to Python 2.6: https://www.python.org/dev/peps/pep-3110/#compatibility
Counter-example: The ruby 1.8 -> 1.9 -> 2.0 upgrade path. 1.9 introduced the whole encoding system, which was a major update at the time. It did break a lot of libraries that handled strings. Still, the change went over fairly quickly, partly because major players in the ruby world (rails) adopted the change. The update also brought clear benefits and it was clearly marked that 1.8 was going to go out of support. There are still some stragglers (centos 6, I'm looking in your direction), but it's clearly accepted that ruby 2.x is the standard that you should be writing code for.
Swift breaks every major version at least but not as often and on a large scale anymore with point releases as with 1.x and 2.x. Has been like that from the beginning and everybody that writes it accepted it.
You reminded me of the java version incompatibility nightmares that once littered the enterprise landscape. If they do that now, it's because their history includes perhaps the worst set of incompatibility jumps of any popular language.