I apologize, I keep making the same mistake. The PyCode_New[WithPosArgs] functions are *not* in the stable ABI or in the limited API, so there's no need to petition the SC, nor do I need Petr's approval.
We may be bound by backwards compatibility for the *cpython* API, but I think that if Cython is okay if we just break this we should be fine. Users of the CPython API are expected to recompile for each new version, and if someone were to be using these functions with the old set of parameters the compiler would give them an error. So let's just choose (E) and d*mn backwards compatibility for these two functions. That means: - Get rid of PyCode_NewWithPosArgs altogether - PyCode_New becomes unstable (and gets a new posinlyargcount argument) On Wed, Sep 1, 2021 at 11:52 AM Guido van Rossum <gu...@python.org> wrote: > (context) > >> Guido van Rossum schrieb am 13.08.21 um 19:24: >> > In 3.11 we're changing a lot of details about code objects. Part of >> this is >> > the "Faster CPython" work, part of it is other things (e.g. PEP 657 -- >> Fine >> > Grained Error Locations in Tracebacks). >> > >> > As a result, the set of fields of the code object is changing. This is >> > fine, the structure is part of the internal API anyway. >> > >> > But there's a problem with two public API functions, PyCode_New() and >> > PyCode_NewWithPosArgs(). As we have them in the main (3.11) branch, >> their >> > signatures are incompatible with previous versions, and they have to be >> > since the set of values needed to create a code object is different. >> (The >> > types.CodeType constructor signature is also changed, and so is its >> > replace() method, but these aren't part of any stable API). >> > >> > Unfortunately, PyCode_New() and PyCode_NewWithPosArgs() are part of the >> PEP >> > 387 stable ABI. What should we do? >> > >> > A. We could deprecate them, keep (restore) their old signatures, and >> create >> > crippled code objects (no exception table, no endline/column tables, >> > qualname defaults to name). >> > >> > B. We could deprecate them, restore the old signatures, and always >> raise an >> > error when they are called. >> > >> > C. We could just delete them. >> > >> > D. We could keep them, with modified signatures, and to heck with ABI >> > compatibility for these two. >> > >> > E. We could get rid of PyCode_NewWithPosArgs(), update PyCode() to add >> the >> > posonlyargcount (which is the only difference between the two), and d*mn >> > the torpedoes. >> > >> > F. Like (E), but keep PyCode_NewWithPosArgs() as an alias for >> PyCode_New() >> > (and deprecate it). >> > >> > If these weren't part of the stable ABI, I'd choose (E). [...] >> > > On Tue, Aug 31, 2021 at 7:07 PM Stefan Behnel <stefan...@behnel.de> > wrote: > >> I also vote for (E). The creation of a code object is tied to interpreter >> internals and thus shouldn't be (or have been) declared stable. >> > > I think you're one of the few people who call those functions, and if even > you think it's okay to break backward compatibility here, I think we should > just talk to the SC to be absolved of having these two in the stable ABI. > (Petr, do you agree? Without your backing I don't feel comfortable even > asking for this.) > > >> I think the only problem with that argument is that code objects are >> required for frames. You could argue the same way about frames, but then >> it >> becomes really tricky to, you know, create frames for non-Python code. >> > > Note there's nothing in the stable ABI to create frames. There are only > functions to *get* an existing frame, to inspect a frame, and to eval it. > In any case even if there was a stable ABI function to create a frame from > a code object, one could argue that it's sufficient to be able to get an > existing code object from e.g. a function object. > > >> Since we're discussing this in the context of PEP 657, I wonder if >> there's >> a better way to create tracebacks from C code, other than creating fake >> frames with fake code objects. >> >> Cython uses code objects and frames for the following use cases: >> >> - tracing generated C code at the Python syntax level >> - profiling C-implemented functions >> - tracebacks for C code >> >> Having a way to do these three efficiently (i.e. with close to zero >> runtime >> overhead) without having to reach into internals of the interpreter >> state, >> code objects and frames, would be nice. >> >> Failing that, I'm ok with declaring the relevant structs and C-API >> functions non-stable and letting Cython use them as such, as we always >> did. >> > > I think others have answered this already -- in any case it's not the > immediate subject of this thread, and I don't have a strong opinion on it. > > -- > --Guido van Rossum (python.org/~guido) > *Pronouns: he/him **(why is my pronoun here?)* > <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/> > -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-change-the-world/>
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