Mailman 3 August 2009 - Python-Dev

socket.makefile and EINTR handling
by Gregory P. Smith Aug. 7, 2009

Aug. 7, 2009

In particular this issue: http://bugs.python.org/issue1628205 I believe we should handle EINTR internally within the socket._fileobject wrapper as nobody using a file-like object should ever expect to get an EINTR. EINTR only comes from using the lowest level system calls. Anyone strongly disagree? -gps

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Summary of Python tracker Issues
by Python tracker Aug. 7, 2009

Aug. 7, 2009

ACTIVITY SUMMARY (07/31/09 - 08/07/09) Python tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue number. Do NOT respond to this message. 2315 open (+39) / 16175 closed (+16) / 18490 total (+55) Open issues with patches: 919 Average duration of open issues: 657 days. Median duration of open issues: 411 days. Open Issues Breakdown open 2283 (+39) pending 31 ( +0) Issues Created Or Reopened (55) … [View More]

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PEP 385: the eol-type issue
by Dirkjan Ochtman Aug. 7, 2009

Aug. 7, 2009

So, I've been not-working on this, which I feel bad about. Suffice it to say the day job has required more of my time then usual for the past few weeks. I want to get back into it, so let's start by re-raising this issue, which Mark Hammond conveniently summarized below. > On 4/07/2009 2:03 PM, Mark Hammond wrote: >> On 4/07/2009 12:30 PM, Nick Coghlan wrote: >>> And since Mercurial doesn't even allow us to say "this is a binary file" >>> the way CVS used to I'm … [View More]currently not seeing any way for that to happen >>> except for win32text to be updated to correctly handle wild cards in >>> combination with negative filters. >> >> I agree with your conclusion. My ruminating on this over the last few >> months leaves me thinking this would involve: >> >> * my older 'accepted but then lost' hg patch to allow an explicit 'none' >> rule for a single file to override wildcards. This was and still is a good idea. It would be very nice if you could un-bitrot it and submit it for inclusion into crew-stable (so that it may land in the next release, which would hopefully be a somewhat near 1.3.2). >> * win32text be enhanced to use a normal versioned file in the root of >> the repo, much like hgingore, where a project can maintain project wide >> rules. I'm thinking that it should take stuff from .hgeols or whatever and apply rules from .hg/hgrc after that, so both may be used (and for backwards compatibility), but it sounds like a good idea in principle. >> * win32text be enhanced such that all python developers, regardless of >> platform, are willing to use this extension, even if the majority of >> files happen to use their native line ending (sauce for the goose is >> sauce for the gander, and all that...) I don't think that is necessary, I will elaborate below. >> * commit hooks be implemented to enforce this - but this should not be >> necessary if the above was implemented and socially enforced. You seem to advocate a two-step approach: enforce line endings through win32text, catch any errors that slipped through in a hook (commit hook is an optional first line of defense, changegroup hooks on the server to protect the rest of the world). I think inverting that approach would be better: have strict hooks on the server to prevent people from pushing inappropriate EOLs, and provide help on configuring win32text as an extra help for developers on Windows who use editors that work better with \r\n. That leaves people to pick their own weapon of choice against propagation of \r\n (e.g. better editor, commit hooks, whatever) while still making sure no inappropriate line endings land in the python.org repositories. It also seems to fit well with the whole consenting adults thing (but that might just be me). On Sun, Jul 19, 2009 at 15:27, Mark Hammond<skippy.hammond(a)gmail.com> wrote: > Sorry Dirkjan - I just noticed I didn't CC you on this mail originally. I'm > wondering if you have any more thoughts on these EOL issues and if there is > anything I can do to help? Taking up the 'none' filter, first, and .hgeols, secondly, in the win32text extension would be wonderfully helpful, since I don't do much development on Windows and am therefore not that familiar with the extension in the first place. Cheers, Dirkjan [View Less]

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Tkinter has many files
by cool-RR Aug. 7, 2009

Aug. 7, 2009

Hello python-dev! I'm a Python programmer, but this is the first time I'm posting on python-dev, and I am not familiar at all with how the Python implementation works -- so this post may be way off. I've recently released a Python application, PythonTurtle<http://pythonturtle.com>, which is packaged using py2exe and InnoSetup. Due to the fact that my program needs to give the user a full Python shell, I've made py2exe package the entire Python standard library with my application. What … [View More]

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(try-except) conditional expression similar to (if-else) conditional (PEP 308)
by ilya Aug. 6, 2009

Aug. 6, 2009

I took a look at the options 1 and 2: x = float(string) except float('nan') if ValueError y = float(string) except ValueError: float('nan') and I think this can be done just as easily with existing syntax: x = try_1(float, string, except_ = float('nan'), if_ = ValueError) y = try_2(float, string, { ValueError: float('nan') }) Here's the full example: ----- example starts ----- def try_1(func, *args, except_ = None, if_ = None): try: return func(*args) … [View More]except if_ as e: return except_ def try_2(func, *args): 'The last argument is a dictionary {exception type: return value}.' dic = args[-1] try: return func(*args[:-1]) except Exception as e: for k,v in dic.items(): if isinstance(e, k): return v raise for string in ['5', 'five']: # x = float(string) except float('nan') if ValueError x = try_1(float, string, except_ = float('nan'), if_ = ValueError) # y = float(string) except ValueError: float('nan') y = try_2(float, string, { ValueError: float('nan') }) print(x, y) ----- example ends ----- As a side note, if I just subscribed to python-dev, is it possible to quote an old email? Below is my manual cut-and-paste quote: ---------- my quote -------------- Nick Coghlan wrote: > P.J. Eby wrote: >> At 05:59 PM 8/5/2009 -0700, Raymond Hettinger wrote: >>> [Jeffrey E. McAninch, PhD] >>>> I very often want something like a try-except conditional expression >>>> similar >>>> to the if-else conditional. >>>> >>>> An example of the proposed syntax might be: >>>> x = float(string) except float('nan') >>>> or possibly >>>> x = float(string) except ValueError float('nan') >>> +1 I've long wanted something like this. >>> One possible spelling is: >>> >>> x = float(string) except ValueError else float('nan') >> I think 'as' would be better than 'else', since 'else' has a different >> meaning in try/except statements, e.g.: >> >> x = float(string) except ValueError, TypeError as float('nan') >> >> Of course, this is a different meaning of 'as', too, but it's not "as" >> contradictory, IMO... ;-) > > (We're probably well into python-ideas territory at this point, but I'll > keep things where the thread started for now) > > The basic idea appears sound to me as well. I suspect finding an > acceptable syntax is going to be the sticking point. > > Breaking the problem down, we have three things we want to separate: > > 1. The expression that may raise the exception > 2. The expression defining the exceptions to be caught > 3. The expression to be used if the exception actually is caught > >>From there it is possible to come up with all sorts of variants. > > Option 1: > > Change the relative order of the clauses by putting the exception > definition last: > > x = float(string) except float('nan') if ValueError > op(float(string) except float('nan') if ValueError) > > I actually like this one (that's why I listed it first). It gets the > clauses out of order relative to the statement, but the meaning still > seems pretty obvious to me. > A further extension (if we need it): result = foo(arg) except float('inf') if ZeroDivisionError else float('nan') The 'else' part handles any other exceptions (not necessarily a good idea!). or: result = foo(arg) except float('inf') if ZeroDivisionError else float('nan') if ValueError Handles a number of different exceptions. > Option 2: > > Follow the lamba model and allow a colon inside this form of expression: > > x = float(string) except ValueError: float('nan') > op(float(string) except ValueError: float('nan')) > > This has the virtue of closely matching the statement syntax, but > embedding colons inside expressions is somewhat ugly. Yes, lambda > already does it, but lambda can hardly be put forward as a paragon of > beauty. > A colon is also used in a dict literal. > Option 3a/3b: > > Raymond's except-else suggestion: > > x = float(string) except ValueError else float('nan') > op(float(string) except ValueError else float('nan')) > [snip] -1 [View Less]

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PEP 385: pruning/reorganizing branches
by Dirkjan Ochtman Aug. 5, 2009

Aug. 5, 2009

So PEP 385 proposes to clean up the old branches we still have lying around in SVN. This list of branch: action items is what I've come up with to do this cleanup. Legend first: - keep-clone means we'll keep that branch in a separate clone - keep-named means we'll keep that branch as a named branch in one of the clones - strip means we won't keep that branch - streamed-merge means that it got merged by committing several new revisions to the other branch - merged-r* means the branch got … [View More]merged in the named revision - merges? means I haven't checked/found out yet whether that branch was ever merged - ? means that your input would be even more helpful than for the other items - some items have no action yet, feel free to treat that as just '?' The actual List: py3k: keep-clone default: keep-clone tk_and_idle_maintenance: keep-clone release26-maint: keep-named release30-maint: keep-named pep-0383: keep-clone py3k-short-float-repr: strip streamed-merge multiprocessing-autoconf: keep-clone? release25-maint: keep-named io-c: keep-clone? py3k-issue1717: keep-clone tlee-ast-optimize: keep-clone release24-maint: keep-named empty: keep-clone? py3k-urllib: keep-clone tnelson-trunk-bsddb-47-upgrade: strip benjaminp-testing: strip py3k-importlib: keep-clone release23-maint: keep-named py3k-importhook: keep-clone ctypes-branch: strip decimal-branch: merged-r58143 bcannon-objcap: keep-clone? p3yk_no_args_on_exc: strip amk-mailbox: keep-clone? twouters-dictviews-backport: keep-clone? bcannon-sandboxing: keep-clone? release22-maint: keep-named theller_modulefinder: strip hoxworth-stdlib_logging-soc: strip partial tim-exc_sanity: merged-r46426 IDLE-syntax-branch: merged-r41480 strip-later ast-objects: strip ast-arena: merged-r41739 jim-doctest: strip ast-branch: merged-r39758 release23-branch: merges? jim-modulator: strip release21-maint: keep-named indexing-cleanup-branch: strip r23c1-branch: merged-r33637 r23b2-branch: merges? anthony-parser-branch: merged-r35460 r23b1-branch: merged-r32490 idlefork-merge-branch: strip getargs_mask_mods: strip cache-attr-branch: strip folding-reimpl-branch: strip streamed-merge r23a2-branch: merges? bsddb-bsddb3-schizo-branch: merged-r31008 r23a1-branch: merged-r30482 py-cvs-vendor-branch: strip DS_RPC_BRANCH: strip streamed-merge SourceForge: strip release22-branch: merged-r24921 r22rc1-branch: strip r22b2-branch: merges? merged-r24426 r22b1-branch: merges? r22a4-branch: merges? r22a3-branch: merges? r22a2-branch: merged-r22674 descr-branch: merged-r22139 release20-maint: keep-named gen-branch: merged-r21181 iter-branch: merged-r20492 r161-branch: merges? cnri-16-start: strip universal-33: merges? None: strip avendor: strip Distutils_0_1_3-branch: strip partial release152p1-patches: merges? string_methods: merged-r13927 PYIDE: strip OSAM: strip PYTHONSCRIPT: strip BBPY: strip jar: merges? alpha100: strip streamed-merge unlabeled-2.36.4: strip partial unlabeled-2.1.4: strip partial unlabeled-2.25.4: strip partial fix-test-ftplib: merged-r66673 trunk-math: py3k-grandrenaming: okkoto-sizeof py3k-ctypes-pep3118: merged-r62597 trunk-bytearray: merged-r61936 libffi3-branch: merged-r61234 alex-py3k: strip cpy_merge: strip py3k-pep3137: merged-r58888 ../ctypes-branch: strip pep302_phase2: strip py3k-buffer: merged-r57181 p3yk-noslice py3k-struni p3yk: rename int_unification unlabeled-1.1.1: strip unlabeled-1.5.4: strip unlabeled-1.1.2: strip unlabeled-2.9.2: strip unlabeled-2.9.4: strip unlabeled-1.5.2: strip unlabeled-2.1.2: strip unlabeled-2.36.2: strip unlabeled-2.108.2: strip unlabeled-2.10.2: strip unlabeled-2.54.2: strip unlabeled-1.3.2: strip unlabeled-1.23.4: strip unlabeled-2.25.2: strip unlabeled-1.2.2: strip unlabeled-1.98.2: strip unlabeled-2.16.2: strip unlabeled-2.3.2: strip unlabeled-1.9.2: strip unlabeled-1.8.2: strip aimacintyre-sf1454481: merged-r46919 tim-current_frames: merged-r50541 bippolito-newstruct: merges? runar-longslice-branch: strip steve-notracing: strip rjones-funccall: merged-r46096 sreifschneider-newnewexcept: merged-r46456 tim-doctest-branch: merged-r36839 blais-bytebuf: strip ../bippolito-newstruct: rename rjones-prealloc: strip sreifschneider-64ints: strip stdlib-cleanup: strip ssize_t: merged-r42382 sqlite-integration: merged-r43514 tim-obmalloc: merged-r43059 Further actions: - implement branch map support in hgsubversion to be able to do named/unnamed/no branch on a branch-by-branch basis - implement splice map support in hgsubversion to be able to convert given merges to hg-native merge data Cheers, Dirkjan [View Less]

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Functionality in subprocess.Popen.terminate()
by Eric Pruitt Aug. 5, 2009

Aug. 5, 2009

In my GSoC project, I have implemented asnychronous I/O in subprocess.Popen. Since the read/write operations are asynchronous, the program may have already exited by the time one calls the asyncread function I have implemented. While it returns the data just fine, I have come across an issue with the TerminateProcess function in Windows: if the program has already exited, when subprocess.Popen.Terminate calls the Windows built-in "TerminateProcess" function, an "access denied" error will occur. … [View More]

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Mercurial migration: help needed
by "Martin v. Löwis" Aug. 5, 2009

Aug. 5, 2009

This is a repost from a month ago. It didn't get much feedback last time. I have now two items. In this thread, I'd like to collect things that ought to be done but where Dirkjan has indicated that he would prefer if somebody else did it. Item 1 ------ The first item is build identification. If you want to work on this, please either provide a patch (for trunk and/or py3k), or (if you are a committer) create a subversion branch. It seems that Barry and I agree that for the maintenance … [View More]

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PEP 385: updating the PEP
by Dirkjan Ochtman Aug. 3, 2009

Aug. 3, 2009

The diff below should reflect changes from the discussion we had last time. Please review. (Some comments may be more appropriate for the other threads I just kicked off.) Cheers, Dirkjan Index: pep-0385.txt =================================================================== --- pep-0385.txt (revision 74294) +++ pep-0385.txt (revision 74296) @@ -59,27 +59,25 @@ often has somewhat unintuitive results for people (though this has been getting better in recent versions of … [View More]Mercurial). -I'm still a bit on the fence about whether Python should adopt cloned -branches and named branches. Since it usually makes more sense to tag releases -on the maintenance branch, for example, mainline history would not contain -release tags if we used cloned branches. Also, Mercurial 1.2 and 1.3 have the -necessary tools to make named branches less painful (because they can be -properly closed and closed heads are no longer considered in relevant cases). +The current proposal is to use named branches for release branches and adopt +cloned branches for feature branches, with one exception to this rule: the 3.x +branches will be kept in separate clones from the 2.x branches. I think this +provides an optimal hybrid approach for Python's uses of branching. -A disadvantage might be that the used clones will be a good bit larger (since -they essentially contain all other branches as well). This can me mitigated by -keeping non-release (feature) branches in separate clones. Also note that it's -still possible to clone a single named branch from a combined clone, by -specifying the branch as in hg clone http://hg.python.org/main/#2.6-maint. -Keeping the py3k history in a separate clone problably also makes sense. +Differences between named branches and cloned branches: -XXX To do: size comparison for selected separation scenarios. +* Tags in a different (maintenance) clone aren't available in the local clone +* Clones with named branches will be larger, since they contain more data +(The Mercurial book discourages the use of named branches, but it is, in this +respect, somewhat outdated. Named branches have gotten much easier to use +since that comment was written, due to improvements in hg.) + Converting branches ------------------- There are quite a lot of branches in SVN's branches directory. I propose to -clean this up a bit, by employing the following the strategy: +clean this up a bit, by following this basic strategy: * Keep all release (maintenance) branches * Discard branches that haven't been touched in 18 months, unless somone @@ -87,6 +85,21 @@ * Keep branches that have been touched in the last 18 months, unless someone indicates the branch can be deprecated +There's a `branch map`_ available that shows info about each branch: + +* keep-clone means we'll keep that branch in a separate clone +* keep-named means we'll keep that branch as a named branch in one of the clones +* strip means we won't keep that branch +* streamed-merge means that it got merged by committing several new revisions + to the other branch +* merged-r* means the branch got merged in the named revision +* merges? means I haven't checked/found out yet whether that branch was ever + merged +* ? means that your input would be even more helpful than for the other items +* some items have no action yet, feel free to treat that as just '?' + +.. _branch map: http://hg.python.org/pymigr/file/tip/all-branches.txt + Converting tags --------------- @@ -95,8 +108,8 @@ we should keep all release tags, and consider other tags for inclusion based on requests from the developer community. I'd like to consider unifying the release tag naming scheme to make some things more consistent, if people feel -that won't create too many problems. For example, Mercurial itself just uses -'1.2.1' as a tag, where CPython would currently use r121. +that won't create too many problems. The current proposal is to bring old +release tags in line with the current practice of release tag naming. Author map ---------- @@ -119,17 +132,19 @@ possible forms of pattern matching. The current Python repository already includes a rudimentary .hgignore file to help with using the hg mirrors. -It might be useful to have the .hgignore be generated automatically from -svn:ignore properties. This would make sure all historic revisions also have -useful ignore information (though one could argue ignoring isn't really -relevant to just checking out an old revision). +Since the current Python repository already includes a .hgignore file (for use +with hg mirrors), we'll just use that. Generating full history of the file +was debated but deemed impractical (because it's relatively hard with fairly +little gain, since ignoring is less important for older revisions). Revlog reordering ----------------- -As an optional optimization technique, we should consider trying a reordering -pass on the revlogs (internal Mercurial files) resulting from the conversion. -In some cases this results in dramatic decreases in on-disk repository size. +As an optional optimization technique, I have performed a reordering pass on +the revlogs (internal Mercurial files) resulting from the conversion. In some +cases this results in dramatic decreases in on-disk repository size. This +especially makes sense for the manifest (where it really helps out quite a lot) +and oft-edited files like NEWS.txt (with an admittedly smaller effect). Other repositories ------------------ @@ -138,7 +153,14 @@ converted. What other projects in the svn.python.org repository should be converted? Do we want to convert the peps repository? distutils? others? +There's now an initial stab at converting the Jython repository. The current +tip of hgsubversion unfortunately fails at some point. Pending investigation. +Other repositories that would like to converted to Mercurial can announce +themselves to me after the main Python migration is done, and I'll take care +of their needs. + + Infrastructure ============== @@ -165,18 +187,34 @@ lines. Open issue: do we check only the tip after each push, or do we check every commit in a changegroup? -* commit mails: we can leverage the notify extension for this +* commit mails: we can leverage the notify extension for this. Emails will + include diffs for each changeset committed against the repository. * buildbots: both the regular and the community build masters must be notified. Fortunately buildbot includes support for hg. I've also implemented this for Mercurial itself, so I don't expect problems here. * check contributors: in the current setup, all changesets bear the username of - committers, who must have signed the contributor agreement. In a DVCS, the - committers are not necessarily the same people who push, and so we can't - check if the committer is a contributor. We could use a hook to check if the - committer is a contributor if we keep a list of registered contributors. + committers, who must have signed the contributor agreement. We might want to + use a hook to check if the committer is a contributor if we keep a list of + registered contributors. Then, the hook might warn users that push a group + of revisions containing changesets from unknown contributors. +End-of-line conversions +----------------------- + +There has been some discussion about the lack of end-of-line conversion support +in Mercurial. While Mercurial comes with a win32text extension that provides +some basic support for converting end-of-line data on a file-name pattern +basis, the lack of exclusion (for specifying broad rules with exceptions) and +the use of hgrc files (which can't be versioned) make it less than ideal. + +I think the primary line of defense for prevention of inappropriate newlines +should be hooks on the server side which basically turn down any changegroup +or changeset introducing such data. The use of the win32text extension (which +can hopefully be improved/extended to support the usage scenarios mentioned +above) and/or a commit-time hook could be the first line of defense. + hgwebdir -------- @@ -185,7 +223,16 @@ build a quick extension to augment the URL rev parser so that it can also take r[0-9]+ args and come up with the matching hg revision. +roundup +------- +We'll come up with an auto-linking plugin for roundup, which can match a +changeset identifier (possibly with a branch prefix), and link it to the +appropriate revision in the hgwebdir instance. Second, the script above (in +the hgwebdir section) will make sure that old links to revision should continue +to work (by pointing to the hg changeset that reflects the svn revision). + + After migration =============== @@ -222,37 +269,32 @@ .. _wiki: http://www.selenic.com/mercurial/wiki/ .. _parts of the developer FAQ: http://www.python.org/dev/faq/#version-control -Think first, commit later? --------------------------- +Proposed workflow +----------------- -In recent history, old versions of Python have been maintained by a select -group of people backporting patches from trunk to release branches. While -this may not scale so well as the development pace grows, it also runs into -some problems with the current crop of distributed versioning tools. These -tools (I believe similar problems would exist for either git, bzr, or hg, -though some may cope better than others) are based on the idea of a Directed -Acyclic Graph (or DAG), meaning they keep track of relations of changesets. +I propose two workflows for the migration of patches between several branches. -Mercurial itself has a stable branch which is a ''strict'' subset of the -unstable branch. This means that generally all fixes for the stable branch -get committed against the tip of the stable branch, then they get merged into -the unstable branch (which already contains the parent of the new cset). This -provides a largely frictionless environment for moving changes from stable to -unstable branches. Mistakes, where a change that should go on stable goes on -unstable first, do happen, but they're usually easy to fix. That can be done by -copying the change over to the stable branch, then trivial-merging with -unstable -- meaning the merge in fact ignores the parent from the stable -branch). +For migration within 2.x or 3.x branches, I propose a patch always gets +committed to the oldest branch where it applies first. Then, the resulting +changeset can be merged using hg merge to all newer branches within that +series (2.x or 3.x). If it does not apply as-is to the newer branch, hg revert +can be used to easily revert to the new-branch-native head, patch in some +alternative version of the patch (or none, if it's not applicable), then commit +the merge. The premise here is that all changesets from an older branch within +the series are eventually merged to all newer branches within the series. -This strategy means a little more work for regular committers, because they -have to think about whether their change should go on stable or unstable; they -may even have to ask someone else (the RM) before committing. But it also -relieves a dedicated group of committers of regular backporting duty, in -addition to making it easier to work with the tool. +The upshot is that this provides for the most painless merging procedure. The +downside is that in the general case, people have to think about the oldest +branch to which the patch should be applied before actually applying it. -Now would be a good time to consider changing strategies in this regard, -although it would be relatively easy to switch to such a model later on. +For migration between 2.x and 3.x branches (which should all be in the same +direction, though I'm not sure what direction is most appropriate here), +changesets should be transplanted (not merged) in some other way. The +transplant extension, import/export and bundle/unbundle work equally well here. +Choosing this approach allows 3.x not to carry all of the 2.x history-since-it- +was-branched, meaning the clone is not as big and the merges not as complicated. + The future of Subversion ------------------------ @@ -281,7 +323,9 @@ I propose that the revision identifier will be the short version of hg's revision hash, for example 'dd3ebf81af43', augmented with '+' (instead of 'M') if the working directory from which it was built was modified. This mirrors -the output of the hg id command, which is intended for this kind of usage. +the output of the hg id command, which is intended for this kind of usage. The +sys.subversion value will also be renamed to sys.mercurial to reflect the +change in VCS. For the tag/branch identifier, I propose that hg will check for tags on the currently checked out revision, use the tag if there is one ('tip' doesn't [View Less]

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In late this am
by Casey Duncan Aug. 3, 2009

Aug. 3, 2009

Going to the Dr., will be in thereafter. -Casey

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