[PATCH 00 of 10] PyPy support

Dan Villiom Podlaski Christiansen danchr at gmail.com
Fri Dec 3 08:51:45 CST 2010

On 2 Dec 2010, at 02:15, Matt Mackall wrote:

> On Wed, 2010-12-01 at 22:34 +0100, Dan Villiom Podlaski Christiansen
> wrote:
>> Hi,
>> This series fixes most of the test suite failures when running
>> Mercurial under PyPy 1.4. I've only tested a pure Python build; the C
>> modules won't compile as PyPy's cpyext interface lacks the
>> PyFile_GetLine and PyErr_SetFromErrnoWithFilename APIs.
> A good benchmark would be running verify.

Currently, PyPy is about twice as slow as CPython in pure builds. I  
haven't been able to get the C extensions working on my Mac, but  
according to the PyPy developers, their C extension wrapper isn't  
terribly fast. One of them looked at mpatch, and described what it  
does as ‘happy nonsense’. I'll look into that once these patches get in.

> In the future, you should stick the patches that are uncontroversial
> first. In this case, that looks like 1, 7, maybe 8, 9, and 10?

Sorry about that, but thanks for the pointers. I've reordered the  
patches in my queue.

> I'd like some explanation of what's going on in 7.

I first tried closing the file handle, but that didn't work. I later  
realised that this was because make_file() could return ‘sys.stdout’.  
Rather than handling it specially in this code, I've added a patch to  
make make_file() duplicate sys.stdout when returning it, so that it  
always results in a new, closable file handle.

> As for the rest, there are numerous places in the Python docs where
> reference counting is described as the primary memory management  
> method.
> In fact, it's the garbage collector, not the reference counter that's
> described as optional.
> If the Pypy people think that diverging from CPython in a way that
> changes semantics so much that we have to audit all our file  
> handling to
> be safe/compatible, they're really not aiming at widespread use of  
> their
> toy, are they?

As others said, reference counting isn't part of the Python language,  
but an implementation detail of CPython.


Dan Villiom Podlaski Christiansen
danchr at gmail.com

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