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Re: [PATCH] Allow "cease invocation" return from Python callback for repos.svn_repos_history2()

From: Alexey Neyman <stilor_at_att.net>
Date: Tue, 23 Mar 2010 17:05:29 -0700

On Tuesday 23 March 2010 03:38:06 pm Роман Донченко wrote:
> Alexey Neyman <stilor_at_att.net> писал в своём письме Fri, 19 Mar 2010
>
> 02:26:28 +0300:
> > ...
> >
> > With stock 1.6.6, it produces the following traceback:
> >
> > ---------------------------------------------------------------------
> >---- svn: Commit blocked by pre-commit hook (exit code 1) with output:
> > Traceback (most recent call last):
> > File "/tmp/c.repo/hooks/pre-commit", line 35, in <module>
> > core.run_app(verify, sys.argv[1], sys.argv[2])
> > File "/usr/local/lib/svn-python/svn/core.py", line 281, in run_app
> > return func(application_pool, *args, **kw)
> > File "/tmp/c.repo/hooks/pre-commit", line 31, in verify
> > repos.svn_repos_replay2(txn_root, "", -1, True, e_ptr, e_baton,
> > None, pool)
> > File "/usr/local/lib/svn-python/libsvn/repos.py", line 311, in
> > svn_repos_replay2
> > return apply(_repos.svn_repos_replay2, args)
> > File "/tmp/c.repo/hooks/pre-commit", line 22, in open_directory
> > repos.svn_repos_history2(self.fs_ptr, path, history_lookup, None,
> > 0, self.base_rev, True, self.pool)
> > File "/usr/local/lib/svn-python/libsvn/repos.py", line 407, in
> > svn_repos_history2
> > return apply(_repos.svn_repos_history2, args)
> > File "/tmp/c.repo/hooks/pre-commit", line 21, in history_lookup
> > raise
> > core.SubversionException(apr_err=core.SVN_ERR_CEASE_INVOCATION,
> > message="Hi from history_lookup")
> > svn.core.SubversionException: ('Hi from history_lookup', 200021)
> > ---------------------------------------------------------------------
> >----
> >
> > Changed to the following code (difference from previous version is
> > that it
> > Py_DECREF's everything):
> >
> > ---------------------------------------------------------------------
> >---- static svn_error_t *callback_exception_error(void)
> > {
> > PyObject *err = PyErr_Occurred();
> > PyObject *svn_module = NULL, *exc_class = NULL;
> > PyObject *message = NULL, *apr_err = NULL;
> > svn_error_t *rv = NULL;
> >
> > if ((svn_module = PyImport_ImportModule((char *)"svn.core")) ==
> > NULL) goto finished;
> > if ((exc_class = PyObject_GetAttrString(svn_module,
> > (char *)"SubversionException")) == NULL)
> > goto finished;
> > if (PyErr_GivenExceptionMatches(exc_class, err))
> > {
> > apr_err = PyObject_GetAttrString(err, (char *)"apr_err");
> > message = PyObject_GetAttrString(err, (char *)"message");
> > if (message && apr_err && PyString_Check(message) &&
> > PyInt_Check(apr_err))
> > rv = svn_error_create(PyInt_AsLong(apr_err), NULL,
> > PyString_AsString(message));
> > }
> > finished:
> > Py_XDECREF(svn_module);
> > Py_XDECREF(exc_class);
> > Py_XDECREF(apr_err);
> > Py_XDECREF(message);
> > return rv ? rv : svn_error_create(SVN_ERR_SWIG_PY_EXCEPTION_SET,
> > NULL, "Python callback raised an exception"); }
> > ---------------------------------------------------------------------
> >----
> >
> > With this, pre-commit produces this traceback:
> >
> > ---------------------------------------------------------------------
> >---- svn: Commit blocked by pre-commit hook (exit code 1) with output:
> > Traceback (most recent call last):
> > File "/tmp/c.repo/hooks/pre-commit", line 35, in <module>
> > core.run_app(verify, sys.argv[1], sys.argv[2])
> > File "/usr/local/lib/svn-python/svn/core.py", line 281, in run_app
> > return func(application_pool, *args, **kw)
> > File "/tmp/c.repo/hooks/pre-commit", line 31, in verify
> > repos.svn_repos_replay2(txn_root, "", -1, True, e_ptr, e_baton,
> > None, pool)
> > File "/usr/local/lib/svn-python/libsvn/repos.py", line 311, in
> > svn_repos_replay2
> > return apply(_repos.svn_repos_replay2, args)
> > SystemError: NULL result without error in PyObject_Call
> > ---------------------------------------------------------------------
> >----
>
> OK, I think I got it. It couldn't find "apr_err", because
> PyErr_Occurred returns the exception _type_, and I'm pretty sure that
> the SystemError is due to not clearing the exception (although I don't
> know for sure, since I switched to PyErr_Fetch, and that automatically
> clears it). Please test with this version, which works for me:
>
> static svn_error_t *callback_exception_error(void)
> {
> PyObject *svn_module = NULL, *svn_exc = NULL;
> PyObject *message = NULL, *apr_err = NULL;
> PyObject *exc, *exc_type, *exc_traceback;
> svn_error_t *rv = NULL;
>
> PyErr_Fetch(&exc_type, &exc, &exc_traceback);
>
> if ((svn_module = PyImport_ImportModule("svn.core")) == NULL)
> goto finished;
> if ((svn_exc = PyObject_GetAttrString(svn_module,
> "SubversionException")) == NULL)
> goto finished;
>
> if (PyErr_GivenExceptionMatches(exc_type, svn_exc))
> {
> Py_DECREF(exc_type);
> Py_DECREF(exc_traceback);
> }
> else
> {
> PyErr_Restore(exc_type, exc, exc_traceback);
> goto finished;
> }
>
> if ((apr_err = PyObject_GetAttrString(exc, "apr_err")) == NULL)
> goto finished;
> if ((message = PyObject_GetAttrString(exc, "message")) == NULL)
> goto finished;
>
> Py_DECREF(exc);
>
> /* A possible improvement here would be to convert the whole
> SubversionException chain. */
> if (PyString_Check(message) && PyInt_Check(apr_err))
> rv = svn_error_create(PyInt_AsLong(apr_err), NULL,
> PyString_AsString(message));
>
> finished:
> Py_XDECREF(svn_module);
> Py_XDECREF(svn_exc);
> Py_XDECREF(apr_err);
> Py_XDECREF(message);
> return rv ? rv : svn_error_create(SVN_ERR_SWIG_PY_EXCEPTION_SET,
> NULL, "Python callback raised an exception"); }
> }

Works for me, thanks! I'll try to write a test case for 'make
check-swig-py'.

Is this going to be checked to trunk only, or could it be checked in to
upcoming 1.6.10 as well? I tried the same code with SVN I am currently
using (1.6.6), it works as well.

Regards,
Alexey.
Received on 2010-03-24 01:06:01 CET

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