Prepare Stackless 3.6

[akruis]

Now that we are on github, we can start working on Stackless 3.6.

Plan

1. Merge all commits which were converted from mercurial into the branches master-slp and upcoming 3.6-slp. These commits are on branch master and 3.6 as well as 3.5-slp. It is important to interleave the branches using the same logic as on mercurial.

   Details:

   • Merge changes into master-slp up to the branch point for 3.6-slp. The branch point for C-Python 3.6 is commit 3c70a99. Up-merge 3.5-slp into master-slp whenever 3.5-slp contains a Stackless specific commit.
   • Create branch 3.6-slp
   • Merge 2a35c93 from 3.6 into 3.6-slp. Up-merge 3.5-slp into 3.6-slp whenever 3.5-slp contains a Stackless specific commit.
   • Merge d2306ce into master-slp. Up-merge 3.6-slp into master-slp whenever 3.6-slp contains a Stackless specific commit.

2. Once all mercurial commits have been merged, switch to the new git workflow. We still merge the C-Python branches into the corresponding Stackless ("-slp") branches, but we develop Stackless fixes in master-slp or the most recent version branch and cherry-pick them to older branches. (There is no change for 2.7-slp).

   Details:

   • Now master-slp and 3.6-slp should contain all fixes from 3.5-slp. Check it.
   • Then merge 3.6 into 3.6-slp
   • Merge master into master-slp. Because we won't up-merge between Stackless version branches, there is no need to synchronise the work on master-slp and 3.6-slp. Cherry-pick Stackless specific commits.

[akruis]

Random Notes

• If HEAD is a merge commit, then git log --graph HEAD^2^! 3c70a99 gives a nice list of the commits to be merged. The last commit is already merged.

• It is really a good idea to enable git rerere. See man git-rerere(1). It records merge conflict resolutions.

• Some Stackless test cases in test_pickle fail. Needs to be fixed, before I continue merging. EDIT: fixed by b63015b from upstream

• I push my working branch to https://github.com/akruis/cpython/tree/slp36 every now and then.

[akruis]

Changes

1. Issue bpo bpo-43737: More useful documentation on behavior of % when divisor is negative python/cpython#25220 introduced test.libregrtest, which broke Stackless/unittests/runAll.py. Fixed.

2. Commit f5c4b99 causes a leak of 2 references in the Stackless test case test_channel.Subclassing.test_init. See issue slp_prepare_slots leaks memory #135.

3. Commit b0f80b0 changes C-Python to use a 16bit word-code instead of byte-code. The changes to Python/ceval.c reveal that our version in 3.x-slp is unmaintainable. It contains a lot of duplicated code. I'll refactor Python/ceval.c, before I merge b0f80b0.

4. Commit 9be7e7b adds _PyObject_FastCall(), _PyCFunction_FastCall() and _PyFunction_FastCall(), a new calling convention avoiding a temporary tuple to pass positional parameters in most cases. I have make these functions Stackless aware. See issue Add Stackless support to all *PyObject_Call* API functions #137.

5. Commit 3cebf93 introduces the frame evaluation API aspect of PEP 523. It causes a compile error in Python/ceval.c, which is simple to fix. Currently I don't oversee how PEP 523 interacts with Stackless calls or pickling of code objects (new field co_extra).

6. Commit eb63645 implements PEP 525 -- Asynchronous Generators. We should add pickling support for them and for various types related to Asynchronous Generators. See issue Separate pickling of generators, coroutines and asynchronous generators #139. In the end I decided to postpone the enhancement request, because I don't have enough spare time and I don't want to delay the release any further.

7. Commit 2eea952 fixes bpo-31095: "fix potential crash during GC". This change causes at least one assertion failure in the Stackless test suite. See issue Replace copied code in pricklepit.c dictview_new #144.

8. Commit d5d7954 revealed a bug in the initialization of Stackless. See issue bomb type not initialized, NULL pointer access on MemoryError #146.

9. Finally some almost trivial issues: Limit in test/test_doctest to low #145 and The Stackless unit-tests emit many DeprecationWarning messages. #147.

[akruis]

Yesterday I created tag v3.6.4-slp and compiled the Windows installer.