[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

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

From: Роман Донченко <DXDragon_at_yandex.ru>
Date: Wed, 24 Mar 2010 01:38:06 +0300

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");
}

Cheers,
Roman.
Received on 2010-03-23 23:38:37 CET

This is an archived mail posted to the Subversion Dev mailing list.