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Python Enhancement Proposals

PEP 200 – Python 2.0 Release Schedule

Jeremy Hylton <jeremy at>

Table of Contents


This PEP describes the Python 2.0 release schedule, tracking the status and ownership of the major new features, summarizes discussions held in mailing list forums, and provides URLs for further information, patches, and other outstanding issues. The CVS revision history of this file contains the definitive historical record.

Release Schedule

[revised 5 Oct 2000]

  • 26-Sep-2000: 2.0 beta 2
  • 9-Oct-2000: 2.0 release candidate 1 (2.0c1)
  • 16-Oct-2000: 2.0 final

Previous milestones

  • 14-Aug-2000: All 2.0 PEPs finished / feature freeze
  • 5-Sep-2000: 2.0 beta 1

What is release candidate 1?

We believe that release candidate 1 will fix all known bugs that we intend to fix for the 2.0 final release. This release should be a bit more stable than the previous betas. We would like to see even more widespread testing before the final release, so we are producing this release candidate. The final release will be exactly the same unless any show-stopping (or brown bag) bugs are found by testers of the release candidate.

Guidelines for submitting patches and making changes

Use good sense when committing changes. You should know what we mean by good sense or we wouldn’t have given you commit privileges <0.5 wink>. Some specific examples of good sense include:

  • Do whatever the dictator tells you.
  • Discuss any controversial changes on python-dev first. If you get a lot of +1 votes and no -1 votes, make the change. If you get a some -1 votes, think twice; consider asking Guido what he thinks.
  • If the change is to code you contributed, it probably makes sense for you to fix it.
  • If the change affects code someone else wrote, it probably makes sense to ask him or her first.
  • You can use the SF Patch Manager to submit a patch and assign it to someone for review.

Any significant new feature must be described in a PEP and approved before it is checked in.

Any significant code addition, such as a new module or large patch, must include test cases for the regression test and documentation. A patch should not be checked in until the tests and documentation are ready.

If you fix a bug, you should write a test case that would have caught the bug.

If you commit a patch from the SF Patch Manager or fix a bug from the Jitterbug database, be sure to reference the patch/bug number in the CVS log message. Also be sure to change the status in the patch manager or bug database (if you have access to the bug database).

It is not acceptable for any checked in code to cause the regression test to fail. If a checkin causes a failure, it must be fixed within 24 hours or it will be backed out.

All contributed C code must be ANSI C. If possible check it with two different compilers, e.g. gcc and MSVC.

All contributed Python code must follow Guido’s Python style guide.

It is understood that any code contributed will be released under an Open Source license. Do not contribute code if it can’t be released this way.

Failing test cases need to get fixed

We need to resolve errors in the regression test suite quickly. Changes should not be committed to the CVS tree unless the regression test runs cleanly with the changes applied. If it fails, there may be bugs lurking in the code. (There may be bugs anyway, but that’s another matter.) If the test cases are known to fail, they serve no useful purpose.

test case         platform    date reported
---------         --------    -------------
test_mmap         Win ME      03-Sep-2000       Windows 2b1p2 prelease
    [04-Sep-2000 tim
     reported by Audun S. Runde
     the mmap constructor fails w/
        WindowsError: [Errno 6] The handle is invalid
     since there are no reports of this failing on other
     flavors of Windows, this looks like to be an ME bug

Open items – Need to be resolved before 2.0 final release

Decide whether cycle-gc should be enabled by default.

Resolve compatibility issues between core xml package and the XML-SIG XML package.

Update Tools/compiler so that it is compatible with list comprehensions, import as, and any other new language features.

Improve code coverage of test suite.

Finish writing the PEPs for the features that went out with 2.0b1(! sad, but realistic – we’ll get better with practice).

Major effort to whittle the bug database down to size. I’ve (tim) seen this before: if you can keep all the open bugs fitting on one screen, people will generally keep it that way. But let it slobber over a screen for a month, & it just goes to hell (no “visible progress” indeed!).

Accepted and in progress

  • Currently none left. [4-Sep-2000 guido]

Open: proposed but not accepted or rejected

  • There are a number of open patches again. We need to clear these out soon.

Previously failing test cases

If you find a test bouncing between this section and the previous one, the code it’s testing is in trouble!

test case         platform    date reported
---------         --------    -------------
test_fork1        Linux       26-Jul-2000
    [28-aug-2000 fixed by cgw; solution is to create copies of
    lock in child process]
    [19-Aug-2000 tim
     Charles Waldman whipped up a patch to give child processes a new
     "global lock":
     While this doesn't appear to address the symptoms we *saw*, it
     *does* so far appear to be fixing the failing cases anyway

test_parser       all         22-Aug-2000
test_posixpath    all         22-Aug-2000

test_popen2       Win32       26-Jul-2000
    [31-Aug-2000 tim
     This died again, but for an entirely different reason:  it uses a
     dict to map file pointers to process handles, and calls a dict
     access function during popen.close().  But .close releases threads,
     which left the internal popen code accessing the dict without a
     valid thread state.  The dict implementation changed so that's no
     longer accepted.  Fixed by creating a temporary thread state in the
     guts of popen's close routine, and grabbing the global lock with
     it for the duration]
    [20-Aug-2000 tim
     changed the _test function to use the "more" cmd
     when == "nt".  This makes test_popen2 pass under
     HOWEVER, the Win98 "more" invents a leading newline out
     of thin air, and I'm not sure that the other Windows flavors
     of "more" also do that.
     So, somebody please try under other Windows flavors!
    [still fails 15-Aug-2000 for me, on Win98 - tim
         test test_popen2 crashed -- exceptions.AssertionError :
     The problem is that the test uses "cat", but there is
     no such thing under Windows (unless you install it).
     So it's the test that's broken here, not (necessarily)
     the code.

test_winreg        Win32      26-Jul-2000
    [works 15-Aug-2000 for me, on Win98 - tim]

test_mmap          Win32      26-Jul-2000
    [believe that was fixed by Mark H.]
    [works 15-Aug-2000 for me, on Win98 - tim]

test_longexp      Win98+?     15-Aug-2000
    [fails in release build,
     passes in release build under verbose mode but doesn't
         look like it should pass,
     passes in debug build,
     passes in debug build under verbose mode and looks like
         it should pass
    [18-Aug-2000, tim:  can't reproduce, and nobody else
     saw it.  I believe there *is* a subtle bug in when using -v, and I'll pursue that,
     but can't provoke anything wrong with test_longexp
     anymore; eyeballing Fred's changes didn't turn up
     a suspect either
     19-Aug-2000, tim: the "subtle bug" in -v is
     actually a feature:  -v masks *some* kinds of failures,
     since it doesn't compare test output with the canned
     output; this is what makes it say "test passed" even
     in some cases where the test fails without -v

test_winreg2      Win32       26-Jul-2000
    [20-Aug-2000 tim - the test has been removed from the project]
    [19-Aug-2000 tim
     This test will never work on Win98, because it's looking for
     a part of registry that doesn't exist under W98.
     The module ( and this test case will be removed
     before 2.0 for other reasons, though.
    [still fails 15-Aug-2000 for me, on Win98 - tim
     test test_winreg2 failed -- Writing: 'Test Failed: testHives',
     expected: 'HKEY_PERFORMANCE_DATA\012'

Open items – completed/fixed

[4-Sep-2000 guido: Fredrik finished this on 1-Sep]
* PyErr_Format - Fredrik Lundh
  Make this function safe from buffer overflows.

[4-Sep-2000 guido: Fred has added popen2, popen3 on 28-Sep]
Add popen2 support for Linux -- Fred Drake

[4-Sep-2000 guido: done on 1-Sep]
Deal with buffering problem with SocketServer

[04-Sep-2000 tim:  done; installer runs; w9xpopen not an issue]
[01-Sep-2000 tim:  make a prerelease available]
Windows ME:  Don't know anything about it.  Will the installer
even run?  Does it need the w9xpopen hack?

[04-Sep-2000 tim:  done; tested on several Windows flavors now]
[01-Sep-2000 tim:  completed but untested except on Win98SE]
Windows installer:  If HKLM isn't writable, back off to HKCU (so
Python can be installed on NT & 2000 without admin privileges).

[01-Sep-200 tim - as Guido said, runtime code in posixmodule.c doesn't
 call this on NT/2000, so no need to avoid installing it everywhere.
 Added code to the installer *to* install it, though.]
Windows installer:  Install w9xpopen.exe only under Win95/98.

[23-Aug-2000 jeremy - tim reports "completed recently"]
Windows:  Look for registry info in HKCU before HKLM - Mark

[20-Aug-2000 tim - done]
Remove and  Paul Prescod (the author)
now wants to make a registry API more like the MS .NET API.  Unclear
whether that can be done in time for 2.0, but, regardless, if we
let out the door we'll be stuck with it forever, and not
even Paul wants it anymore.

[24-Aug-2000 tim+guido - done]
Win98 Guido:  popen is hanging on Guido, and even freezing the
whole machine.  Was caused by Norton Antivirus 2000 (6.10.20) on
Windows 9x.  Resolution: disable virus protection.

Accepted and completed

  • Change meaning of x escapes - PEP 223 - Fredrik Lundh
  • Add U1234678 escapes in u”” strings - Fredrik Lundh
  • Support for opcode arguments > 2**16 - Charles Waldman SF Patch 100893
  • “import as” - Thomas Wouters Extend the ‘import’ and ‘from … import’ mechanism to enable importing a symbol as another name. (Without adding a new keyword.)
  • List comprehensions - Skip Montanaro Tim Peters still needs to do PEP.
  • Restore old os.path.commonprefix behavior Do we have test cases that work on all platforms?
  • Tim O’Malley’s cookie module with good license
  • Lockstep iteration (“zip” function) - Barry Warsaw
  • SRE - Fredrik Lundh [at least I think it’s done, as of 15-Aug-2000 - tim]
  • Fix xrange printing behavior - Fred Drake Remove the tp_print handler for the xrange type; it produced a list display instead of ‘xrange(…)’. The new code produces a minimal call to xrange(), enclosed in (... * N) when N != 1. This makes the repr() more human readable while making it do what reprs are advertised as doing. It also makes the xrange objects obvious when working in the interactive interpreter.
  • Extended print statement - Barry Warsaw PEP 214 SF Patch #100970
  • interface to poll system call - Andrew Kuchling SF Patch 100852
  • Augmented assignment - Thomas Wouters Add += and family, plus Python and C hooks, and API functions.
  • module - Barry Warsaw


  • Extended slicing on lists - Michael Hudson Make lists (and other builtin types) handle extended slices.
  • Compression of Unicode database - Fredrik Lundh SF Patch 100899 At least for 2.0b1. May be included in 2.0 as a bug fix.
  • Range literals - Thomas Wouters SF Patch 100902 We ended up having a lot of doubt about the proposal.
  • Eliminated SET_LINENO opcode - Vladimir Marangozov Small optimization achieved by using the code object’s lnotab instead of the SET_LINENO instruction. Uses code rewriting technique (that Guido’s frowns on) to support debugger, which uses SET_LINENO. for (working at the time) patches

    Discussions on python-dev:

  • test harness for C code - Trent Mick


  • ‘indexing-for’ - Thomas Wouters Special syntax to give Python code access to the loop-counter in ‘for’ loops. (Without adding a new keyword.)


Last modified: 2023-09-09 17:39:29 GMT