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by kokada5 hours ago |
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upvoteby llimllib4 hours ago|
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3.15: https://docs.python.org/3.15/whatsnew/3.15.html#whatsnew315-...
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upvoteby javcasas3 hours ago|
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> When an AttributeError on a builtin type has no close match via Levenshtein distance, the error message now checks a static table of common method names from other languages (JavaScript, Java, Ruby, C#) and suggests the Python equivalent

Oh, that is such a nice thing.

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upvoteby fulafel54 minutes ago|
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It's unrelated to the lazy keyword. Instead it's another feature related to error messages.

The example:

  >> 'hello'.toUpperCase()
  Traceback (most recent call last):
  ...
  AttributeError: 'str' object has no attribute 'toUpperCase'. Did you mean '.upper'?
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upvoteby estebank31 minutes ago|
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In the Rust toolchain we've done the same. It just so happens that rustdoc already has introduced annotations for "aliases" so that when someone searches for push and it doesn't exist, append would show up. Having those annotations already meant that bootstrapping the feature to check the aliases during name resolution errors in rustc was almost trivial. I love it when improving one thing improves another indirectly too.

I really appreciate them going out of their way to do this, being quite aware of the hidden complexity in doing it.

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upvoteby tuveson11 minutes ago|
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I’ve often thought it would be funny if instead of an error message for stuff like this, a language could be designed to be “typo-insensitive”. If a method or function call is similar enough to an existing one or a common one from other languages, to just have it silently use that.
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upvoteby MarkusQ2 minutes ago|
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I hope you mean "funny" in the "hilarity ensues" sense.

Because the alternative is a rather sociopathic level of schadenfreude.

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upvoteby embedding-shape1 hours ago|
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Now I'm wishing for a single cross-language library, that I can somehow inject into every compiler/runtime/checker to get this, but with a single source of truth and across a wide range of languages. I hit this damn issue all the time, writing code in one language for another, would truly be a bliss to have that problem solved once and for all.
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upvoteby estebank24 minutes ago|
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If you had a "canonical datastructure database", you could have very short annotations on every standard library for any language that indexes a function to their canonical name. After that you only need to update the database.
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upvoteby kzrdude3 hours ago|
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What benefit does the lazy import have here - if we use the value in a type hint at module scope anyway? Would that require Deferred evaluation of annotations -- which I don't think are enabled by default?
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upvoteby js22 hours ago|
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Type annotations are lazily evaluated by moving them behind a special annotations scope as of 3.14:

https://peps.python.org/pep-0649/

https://docs.python.org/3/reference/compound_stmts.html#anno...

With 3.15, using lazy typing imports is more or less an alternative to putting such imports behind an "if TYPE_CHECKING" guard.

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upvoteby kzrdude2 hours ago|
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Ah, thanks for the update. My only check before asking was to check if the future feature for annotations had been enabled by default yet. It has then effectively been abandoned instead, I guess.
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upvoteby js21 hours ago|
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Yup, "from __future__ import annotations" will eventually be removed:

> from __future__ import annotations (PEP 563) will continue to exist with its current behavior at least until Python 3.13 reaches its end-of-life. Subsequently, it will be deprecated and eventually removed.

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upvoteby toxik1 hours ago|
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So the future behavior is deprecated before it ever became the default?
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upvoteby nyrikki37 minutes ago|
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It was an abandoned path even before 3.10, it just took longer to implement 649 and 749 than they expected.

But this is a "...will continue to exist with its current behavior at least..." is an important bit there.

From pep-0749:

     Sometime after the last release that did not support PEP 649 semantics (expected to be 3.13) reaches its end-of-life, from __future__ import annotations is deprecated. Compiling any code that uses the future import will emit a DeprecationWarning. This will happen no sooner than the first release after Python 3.13 reaches its end-of-life, but the community may decide to wait longer.
It has a good overview of the history.

https://peps.python.org/pep-0749/

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upvoteby js238 minutes ago|
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Correct. Before the "from __future__ import annotations" behavior that converts annotations to strings became the default, they figured out a better mechanism for circular type annotations (making them lazy) that is implicitly backwards compatible and that didn't need to be guarded behind a future statement.

Ironically, the new default behavior (making type annotation evaluation lazy) is not backwards compatible with the "from __future__ import annotations" behavior of converting annotations to strings, so they can't just rip out "from __future__ import annotations" and instead it needs to be deprecated and removed over multiple releases.

Oh, what tangled webs we weave! :-)

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upvoteby athorax2 hours ago|
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[dead]
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upvoteby karpetrosyan4 hours ago|
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Note that you can work around it by implementing `def __getattr__(name: str) -> object:` at the module level on earlier Python versions
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upvoteby saghm4 hours ago|
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Somehow I have no trouble imagining this being used as a rationale to avoid unnecessary "magic" to the language for years
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upvoteby wrmsr3 hours ago|
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[dead]
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upvoteby boxed5 hours ago|
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Yes, 3.15+
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upvoteby alcazar1 hours ago|
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[dead]
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upvoteby rad1205 hours ago|
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Python is such a weird language. Lazy imports are a bandaid for AI code base monstrosities with 1000 imports (1% of which are probably Shai Hulud now).

And now even type imports are apparently so slow that you have to disable them if unused during the normal untyped execution.

If Instagram or others wants a professional language, they should switch to Go or PHP instead of shoehorning strange features into a language that wasn't built for their use cases.

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upvoteby stingraycharles5 hours ago|
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> Python is such a weird language. Lazy imports are a bandaid for AI code base monstrosities with 1000 imports

Just because you don’t like a feature doesn’t mean it’s because of AI and bad code.

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upvoteby xtajv2 hours ago|
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Too much syntactic sugar causes cancer of the semicolon.
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upvoteby sigmoid104 hours ago|
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I think this is just a natural consequence of an easy-to-use package system. The exact same story as with node. If you don't want lots of imports, don't make it so damn easy to pile them into projects. I'm frankly surprised we still see so few supply chain attacks, even though they picked up their cadence dramatically.
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upvoteby saghm4 hours ago|
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This seems a lot more due to an import running arbitrary code because stuff can happen in the top-level of a module rather than only happening in functions. From what I can tell, it seems pretty common for dynamically typed languages and pretty much entirely absent from statically typed ones, which tend to have a main function that everything else happens inside transitively. I guess this makes it easy if what you're writing is something that runs with no dependencies, but it's a pretty terrible experience as soon as you try to introduce the concept of a library.
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upvoteby kokada4 hours ago|
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> it seems pretty common for dynamically typed languages and pretty much entirely absent from statically typed ones

Counter-example is Go and init() function.

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upvoteby saghm3 hours ago|
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Interesting, I had no idea that existed! I still think there's a a difference between "here's a hook you can use to run stuff earlier" and "importing any module is fundamentally the same as running it as a script unless the module happens to use a special conditional to wrap stuff inside of" though (and I say this as someone who doesn't go out of his way to defend Go design decisions)
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upvoteby assbuttbuttass1 hours ago|
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Also C++/Java static initialization, C# static constructors, or Rust global variable initialization, ...

Most languages have this feature Afaik

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upvoteby stevesimmons4 hours ago|
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What would your alternative look like?
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upvoteby tremon2 hours ago|
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True, but this is yet another code path that isn't exercised until specific conditions happen. That means even more latent application behaviour can go undetected by unit testing and security profiling until the moon is in the right phase, which is a boon for submarine attacks.
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upvoteby novov4 hours ago|
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Empirically, I have used the current accepted way to do lazy imports (import statement inside a function) before AI coding was even a mainstream thing, for personal code that sometimes needs a heavy import and sometimes doesn’t.

The lazy statement would be an improvement as it allows one to see all the imports at the top where you expect them to be.

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upvoteby afH124 hours ago|
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As a now deleted comment pointed out, lazy imports had been requested forever. They were rejected forever and were accepted just when BigCorps wanted them.

Python-dev now is paid to shore up the failed Instagram stack.

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upvoteby zem12 minutes ago|
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both lazy imports and free threading have been proposed ages ago, they both went through several iterations before a good design was settled upon and made it into the language.

in the case of lazy imports the big corps were the ones doing the experimentation and iteration. the feature didn't make it into the language "just when big corps wanted them"; the instagram stack you allude to already had its own fork of cpython with lazy imports added years ago, and that is not the design that ended up getting adopted by upstream cpython, though some of the people working on it also collaborated on the PEP that finally did make it in.

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upvoteby Daishiman1 hours ago|
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It was accepted just as multiple large corporations with competent teams of internal tool departments ended up forking the interpreter to support lazy imports and demonstrated empirically that the idea has merit.
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upvoteby brookst4 hours ago|
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I too am outraged that a product would prioritize its biggest users.
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upvoteby saghm4 hours ago|
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Is the biggest user larger than the combined set of individual users who had asked for (or would benefit from) the same thing? I honestly don't know, but I don't think that things are always as simple as you're implying in a world where we have the collective action problem.
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upvoteby brookst3 hours ago|
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If you’re asking some some kind of abstract moral value sense, I have idea.

If you’re asking whether project leads give more weight to a single, tangible, vocal stakeholder than they do to unknown numbers of anonymous and lightly-engaged stakeholders? Yes.

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upvoteby WorldMaker1 hours ago|
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Not to mention when the single, tangible, vocal stakeholder can also be asked to be responsible for documentation (PEPs, etc) and PRs. Especially in open source there is a huge difference between "a lot of people asked about this" and "one person asked about this, but was passionate enough about it and open enough to following the process and the feedback loops to champion it all the way across the finish line".
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upvoteby saghm43 minutes ago|
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I don't have any issue with what you're saying if that's what happened. There's quite a gap between that sort of reasoned explanation and treating concerns about large stakeholders versus large numbers of small one with derision.
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upvoteby saghm3 hours ago|
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I mean, yes, demonstrably, the phenomenon you're describing happens. Your previous comment seems pretty sarcastically dismissing the idea that someone could disagree with this being a good thing though, and I was making a counterargument against the underlying opinion that seemed apparent.
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upvoteby 3 hours ago|
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upvoteby formerly_proven4 hours ago|
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On most unix-likes all "imports" via shared libraries (e.g. in C / C++) are lazy by default.
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upvoteby 4 hours ago|
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upvoteby ziml774 hours ago|
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But also great for speed. Larger libraries can take a measurable amount of time to import (even if they have no transitive dependencies). If only some of your code paths actually need the large library then it makes sense to import it lazily. Without lazy you have to do it conditionally which can lead to the imports happening in strange places rather than all being listed out at the top of the file.
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