1. 14 Nov, 2019 12 commits
    • Kirill Smelkov's avatar
      errors: New package · a245ab56
      Kirill Smelkov authored
      With just one function - errors.New() - to create new error with given
      This will be soon used in Pyx/nogil context package to create context.canceled
      and context.deadlineExceeded errors.
      Pyx/nogil only for now.
    • Kirill Smelkov's avatar
      libgolang: Start providing interfaces · 5a99b769
      Kirill Smelkov authored
      - interface is analog of interface{} in Go.
      - error is analog of error in Go.
      For now the interfaces are implemented via classic C++ scheme via
      inheritance and additional vtable field in pointed object.
      In the future we might want to consider reworking that to Go-style
      interfaces without predeclaring which interfaces a class implements.
      Top-level documentation is TODO.
      Interfaces will be soon needed to describe Context interface in C
      context package.
    • Kirill Smelkov's avatar
      golang.pxd: Expose missing memory-management bits · 274afa3f
      Kirill Smelkov authored
      - refptr==refptr  (e.g. to compare whether returned error object is
        something particular)
      - adoptref() and newref()
      - object (exposed as gobject not to be confused with builtin pyx
        "object" referring to python object)
      All this will be soon used in C version of context package.
    • Kirill Smelkov's avatar
      context: Provide package documentation · 9216e2db
      Kirill Smelkov authored
      Briefly describe provided functionality instead of only referring to
      https://golang.org/pkg/context and https://blog.golang.org/context.
    • Kirill Smelkov's avatar
      libgolang: Rename refobj -> object · b2253abf
      Kirill Smelkov authored
      Thinking a bit more after e82b4fab (libgolang: Objects refcounting
      (initial draft)) and working on interfaces as part of context pyx -> C
      move, I've came to conclusion that the better name for on-heap objects
      managed by libgolang is just "object" without "ref" prefix.
      -> Rename refobj -> object and amend its documentation correspondingly.
    • Kirill Smelkov's avatar
      libgolang: Provide std::hash<refptr> · af4a8d80
      Kirill Smelkov authored
      So that refptr<T> could be used as keys in e.g. dict (unordered_map) or
      set (unordered_set). set<refptr> will soon be used by C version of
      context package.
    • Kirill Smelkov's avatar
      libgolang: Provide select(vector<_selcase>) · 66e1e756
      Kirill Smelkov authored
      We already provide select for array and std::initializer_list. However
      when cases are constructed at runtime dynamically both array and
      initializer_list are not convenient to use.
      -> Provide select() overload that accepts vector<_selcase>.
      This functionality will soon be used in C version of context package.
    • Kirill Smelkov's avatar
      sync: Fixup package documentation · 85df1e40
      Kirill Smelkov authored
      - indicated that WorkGroup is not provided in Go version (amends
        40f3b90c "sync: Provide package documentation").
      - fix typo in sync.pxd subject (amends 34b7a1f4 "golang: Expose Sema and
        Mutex as public Python and Cython/nogil API")
    • Kirill Smelkov's avatar
      golang: tests: Silence inspect deprecation warning · 45f4df9e
      Kirill Smelkov authored
      Every time tests are run under Python3 the following warnings are printed:
          .../golang/golang_test.py:990: DeprecationWarning: inspect.getargspec() is deprecated since Python 3.0, use inspect.signature() or inspect.getfullargspec()
            assert inspect.formatargspec(*inspect.getargspec(MyClass.zzz)) == '(self, v, x=2, **kkkkwww)'
          .../golang/golang_test.py:990: DeprecationWarning: `formatargspec` is deprecated since Python 3.5. Use `signature` and the `Signature` object directly
            assert inspect.formatargspec(*inspect.getargspec(MyClass.zzz)) == '(self, v, x=2, **kkkkwww)'
      However since we are not going to drop Python2 support soon, and there is no
      reffered "use-instead" functionality on Python2, let's simply silence the
      warning for now.
    • Kirill Smelkov's avatar
      context: Switch to comparing value keys by identity instead of equality · 281defb2
      Kirill Smelkov authored
      It will be some extra work to define general equality when moving
      context code into C. However that is unnecessary as usually a key is
      specific to one particular package, and value associated with that key
      is struct, or some other aggregate, that is holding all package-specific
      context values.
      Switching to compare keys by identity preserves that use-case while
      making transition to C easier.
    • Kirill Smelkov's avatar
      context: Don't use dict in _ValueCtx · f76c11f3
      Kirill Smelkov authored
      We always store just one key in there.
      This will simplify transition to C.
    • Kirill Smelkov's avatar
      context: tests: Don't compare .done() by "is" · 20761c55
      Kirill Smelkov authored
      This continues 2c8063f4 (*: Channels must be compared by ==, not by "is"
      even for nilchan) and changes comparision of .done() for different
      contexts from "is" to ==.
      The reason is that soon we are going to move contexts into C, and this
      way in context tree there potentially can be PyCtx -> CCtx -> PyCtx
      chains, and while all those contexts could have the same C-level channel,
      it would be difficult to propagate the knowledge that Python-level
      pychan wrapper should be also exactly the same.
      We already treat channel objects as pointers and require to compare them
      by ==, so there should be no loss here. However to keep performance of
      we continue to require that .done() for a particular python context
      object returns exactly the same channel object every time.
  2. 13 Nov, 2019 1 commit
  3. 11 Nov, 2019 2 commits
  4. 07 Nov, 2019 10 commits
    • Kirill Smelkov's avatar
      *: Suppress DeprecationWarning on `import imp` · ec2e882b
      Kirill Smelkov authored
      As of 20191107 imp is present in Python 3.8 source tree and is _used_
      there - see e.g.
      And they say imp will be there until at least Python 4 - see e.g.
      This fixes test_defer_excchain_dump failure under python3-dbg, where
      E           Failed: not equal:
      E           Differences (unified diff with -expected +actual):
      E               @@ -1,4 +1,6 @@
      E               +PYGOLANG/golang/_gopath.py:37: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
      E               +  import imp
      was added into traceback printed on stderr.
      Fixes: bb9a94c3 (golang: Teach defer to chain exceptions (PEP 3134) even on Python2)
    • Kirill Smelkov's avatar
      time: Move/Port timers to C++/Pyx nogil · b073f6df
      Kirill Smelkov authored
      Provide time.Ticker, time.Timer and friends that can be used directly
      from C++ and Pyx/nogil codes. Python-level classes become small wrapper
      around pyx/nogil ones.
      This is the first patch that moves to Pyx/nogil classes that are
      dynamically allocated on heap. refptr<T> is used to automatically manage
      lifetime of such objects. At Pyx level exposed API is very similar to
      Python-one, while internally it uses refptr<T> and friends.
    • Kirill Smelkov's avatar
      libgolang: Switch _chan refcounting to refobj · e614d641
      Kirill Smelkov authored
      Refobj was just added in previous patch as the class that provides base
      functionality for reference-counted objects.
    • Kirill Smelkov's avatar
      libgolang: Objects refcounting (initial draft) · e82b4fab
      Kirill Smelkov authored
      Since we are going to move more pygolang functionality into C++ (timers,
      context, ...), and since C++ does not have garbage collector, we will
      need to find a way to automatically manage memory in leak/error free way.
      Let's do this via refptr<T> smart pointer (inspired by WebKit's RefPtr<T>),
      which, similarly to chan<T> automatically manages pointed object's
      lifetime through reference counting.
      refptr<T> will be used in follow-up patches.
      Top-level documentation is TODO.
    • Kirill Smelkov's avatar
      golang: Provide way to wrap pyx/nogil-level chan[T] into pychan · 07f9430d
      Kirill Smelkov authored
      This will be needed in Python-wrappers for C-level code which exposes
      channels. For example in time package whose implementation will soon be
      moved to nogil world fully.
    • Kirill Smelkov's avatar
      readme: Provide more detailed example for pychan -> chan[T] conversion · 69b80926
      Kirill Smelkov authored
      3121b290 (golang: Teach pychan to work with channels of C types, not
      only PyObjects) added ability to convert pychan to chan[T], but
      described that ability only briefly in README. Provide more details in
      that description before we add description and implementation for
      reflexive pychan <- chan[T] wrapping.
    • Kirill Smelkov's avatar
      libgolang: Split time and sync into their own packages · 1a9dae3b
      Kirill Smelkov authored
      We already have some sync functionality implemented in C++ (e.g.
      sync.Once, sync.WaitGroup) and we are going to add more and also move
      timers implementation to C++. It is getting crowded for that
      functionality to still live in libgolang.{h,cpp}
      -> Split sync & time functionality into their own C++ packages (still
      built-into libgolang.so)
    • Kirill Smelkov's avatar
      time: Provide package documentation · 419c8950
      Kirill Smelkov authored
      Briefly describe provided functionality instead of only referring to
    • Kirill Smelkov's avatar
      sync: Provide package documentation · 40f3b90c
      Kirill Smelkov authored
      Briefly describe provided functionality instead of only referring to
    • Kirill Smelkov's avatar
      pyx.build: Extension.depends += sync.pxd, time.pxd · b06ec3d4
      Kirill Smelkov authored
      Make built extensions depend on golang/{sync,time}.pxd and rebuild if
      those files change. A bit overkill to depend globally, but more correct,
      since an extension that is using pygolang can be using those packages.
      Before the patch - without those depends - since distutils does not
      implement proper dependency tracking, extensions - even those that
      actually depend on sync/time pxd, were not rebuilt.
      sync.pxd was missed to be added in 34b7a1f4 (golang: Expose Sema and
      Mutex as public Python and Cython/nogil API). time.pxd was missed to be
      added in ce8152a2 (pyx api: Provide sleep).
  5. 06 Nov, 2019 3 commits
  6. 04 Nov, 2019 6 commits
  7. 31 Oct, 2019 1 commit
    • Kirill Smelkov's avatar
      libgolang: Fix build with old gcc · 77719d8a
      Kirill Smelkov authored
      Gcc 5.4 from Ubuntu 16.04 LTS complains e.g.
          ./golang/libgolang.h: In function ‘golang::_selcase golang::_selrecv_(golang::_chan*, void*, bool*)’:
          ./golang/libgolang.h:227:5: sorry, unimplemented: non-trivial designated initializers not supported
      The problem started to appear after 47111d3e (libgolang: Teach select to accept
      inplace tx data) when we moved _selcase.ptxrx inside union.
      Let's add workaround for older compilers, even though e.g. gcc 8.3 from Debian
      10 accepts existing code just fine.
  8. 30 Oct, 2019 1 commit
    • Kirill Smelkov's avatar
      sync: Move/Port WaitGroup to C++/Pyx nogil · b316e504
      Kirill Smelkov authored
      Provide sync.WaitGroup that can be used directly from C++ and Pyx/nogil codes.
      Python-level sync.WaitGroup becomes small wrapper around pyx/nogil one.
      Python-level tests should be enough to cover C++/Pyx functionality at
      zero-level approximation.
  9. 24 Oct, 2019 1 commit
  10. 22 Oct, 2019 1 commit
    • Kirill Smelkov's avatar
      libgolang: Expose defer as public C++ API · 1d153a45
      Kirill Smelkov authored
      Libgolang, since 3b241983 (Port/move channels to C/C++/Pyx), already had
      defer macro implemented and used, but only internally. The reason it was
      not yet exposed as public API is that there is a difference with Go's
      defer in that deferred function is called at end of current scope
      instead of end of current function, and I was a bit reluctant to expose
      defer with different-than-Go semantic.
      However even with this difference defer is useful, and the difference
      can be documented. Unfortunately it is not easy to correctly fix the
      difference, so the most practical way for now is to expose defer as it is.
      I've also contemplated how to avoid using macro, but without a macro,
      users will have to explicitly declare placeholder variable for every
      defer call which goes against usability.
      Since defer is exposed as macro, I've also contemplated to expose it as
      something like `libgolang_defer` with the idea to avoid name conflicts,
      and so that users - that are using defer - will be doing `#define defer
      libgolang_defer`. However I ended up not doing that and exposing `defer`
      macro with its own name. My rationale is:
      - grepping /usr/include/ for \<defer\> on my system did not showed any
        real usage.
      - Qt also #defines `slots` and `signals` and that does not cause
        problems in practice.
      -> expose `defer` macro into public C++ API as is, so that it can be
      used not only inside libgolang.cpp . For example I myself need defer
      functionality in C++ part of wendelin.core.
  11. 18 Oct, 2019 2 commits
    • Kirill Smelkov's avatar
      golang: Fix recover to clear current exception · 9e6ff8bd
      Kirill Smelkov authored
      Else the exception, even if it was recovered from, will be included as
      cause for next raised exception. See added test for details.
    • Kirill Smelkov's avatar
      golang: Teach defer to chain exceptions (PEP 3134) even on Python2 · bb9a94c3
      Kirill Smelkov authored
      Python3 chains exceptions, so that e.g. if exc1 is raised and, while it
      was not handled, another exc2 is raised, exc2 will be linked to exc1 via
      exc2.__context__ attribute and exc1 will be included into exc2 traceback
      printout. However many projects still use Python2 and there is no
      similar chaining functionality there. This way exc1 is completely lost.
      Since defer code is in our hands, we can teach it to implement exception
      chaining even on Python2 by carefully analyzing what happens in
      Implementing chaining itself is relatively easy, but is only part of the
      story. Even if an exception is chained with its cause, but exception
      dump does not show the cause, the chaining will be practically useless.
      With this in mind this patches settles not only on implementing chaining
      itself, but on also giving a promise that chained cause exceptions will
      be included into traceback dumps as well.
      To realize this promise we adjust all exception dumping funcitons in
      traceback module and carefully install adjusted
      traceback.print_exception() into sys.excepthook. This amends python
      interactive sessions and programs run by python interpreter to include
      causes in exception dumps. "Careful" here means that we don't change
      sys.excepthook if on golang module load we see that sys.excepthook was already
      changed by some other module - e.g. due to IPython session running
      because IPython installs its own sys.excepthook. In such cases we don't
      install our sys.excepthook, but we also provide integration patches that
      add exception chaining support for traceback dump functionality in
      popular third-party software. The patches (currently for IPython and
      Pytest) are activated automatically, but only when/if corresponding
      software is imported and actually used. This should give practically
      good implementation of the promise - a user can now rely on seeing
      exception cause in traceback dump whatever way python programs are run.
      The implementation takes https://pypi.org/project/pep3134/ experience
      into account [1]. peak.utils.imports [2,3] is used to be notified when/if
      third-party module is imported.
      [1] https://github.com/9seconds/pep3134/
      [2] https://pypi.org/project/Importing/
      [3] http://peak.telecommunity.com/DevCenter/Importing
      This patch originally started as hacky workaround in wendelin.core
      because in wcfs tests I was frequently hitting situations, where
      exception raised by an assert was hidden by another exception raised in
      further generic teardown check. For example wcfs tests check that wcfs
      is unmounted after every test run [4] and if that fails it was hiding
      problems raised by an assert. As the result I was constantly guessing
      and adding code like [5] to find what was actually breaking. At some
      point I added hacky workaround for defer to print cause exception not to
      loose it [6]. [7] has more context and background discussion on this topic.
      [4] https://lab.nexedi.com/kirr/wendelin.core/blob/49e73a6d/wcfs/wcfs_test.py#L70
      [5] https://lab.nexedi.com/kirr/wendelin.core/blob/49e73a6d/wcfs/wcfs_test.py#L853-857
      [6] kirr/wendelin.core@c00d94c7
      [7] zodbtools!13 (comment 81553)
      After this patch, on Python2
      is no longer just a syntatic sugar for