matplotlib-devel

[matplotlib-devel] imread() in master branch doesn't work

[Benjamin R. <ben...@ou...>]

Tried using plt.imread() today on a PNG file, and I am getting this PyCXX
error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ben/Programs/matplotlib/lib/matplotlib/pyplot.py", line 1746,
in imread
    return _imread(*args, **kwargs)
  File "/home/ben/Programs/matplotlib/lib/matplotlib/image.py", line 1218,
in imread
    return handler(fd)
TypeError: PyCXX: Error creating object of type N2Py6ObjectE from (nil)

Using master branch on Python 2.7 on 32-bit Ubuntu Oneric.  Seems to happen
to both color and b&w images.  scipy.ndimage.imread() still works fine,
though.

Ben Root

Re: [matplotlib-devel] imread() in master branch doesn't work

[Eric F. <ef...@ha...>]

On 01/14/2012 09:02 AM, Benjamin Root wrote:
> Tried using plt.imread() today on a PNG file, and I am getting this
> PyCXX error:
>
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
>    File "/home/ben/Programs/matplotlib/lib/matplotlib/pyplot.py", line
> 1746, in imread
>      return _imread(*args, **kwargs)
>    File "/home/ben/Programs/matplotlib/lib/matplotlib/image.py", line
> 1218, in imread
>      return handler(fd)
> TypeError: PyCXX: Error creating object of type N2Py6ObjectE from (nil)
>
> Using master branch on Python 2.7 on 32-bit Ubuntu Oneric.  Seems to
> happen to both color and b&w images.  scipy.ndimage.imread() still works
> fine, though.
>
> Ben Root

I get the same thing with master on 64-bit ubuntu natty, but not with 
v1.1.x.  Mike did quite a bit of work on src/_png.cpp between those two. 
  The most recent commit to that file is not causing the problem, but I 
have not tracked it down beyond that.

Eric

Re: [matplotlib-devel] imread() in master branch doesn't work

[Michael D. <md...@st...>]

I can't confirm this on RHEL5 64-bit or Fedora 16 64-bit.

Have you tried removing the build and installed directories and 
rebuilding from scratch?

I'm shooting in the dark, but does the attached patch resolve your issue?

diff --git a/src/_png.cpp b/src/_png.cpp
index 9437c87..c17dec9 100644
--- a/src/_png.cpp
+++ b/src/_png.cpp
@@ -553,7 +553,7 @@ _png_module::_read_png(const Py::Object& py_fileobj, 
const b

      if (PyErr_Occurred()) {
          Py_DECREF((PyObject *)A);
-        return NULL;
+        throw Py::Exception();
      } else {
          return (PyObject *)A;

Mike

On 01/14/2012 04:51 PM, Eric Firing wrote:
> On 01/14/2012 09:02 AM, Benjamin Root wrote:
>> Tried using plt.imread() today on a PNG file, and I am getting this
>> PyCXX error:
>>
>> Traceback (most recent call last):
>>     File "<stdin>", line 1, in<module>
>>     File "/home/ben/Programs/matplotlib/lib/matplotlib/pyplot.py", line
>> 1746, in imread
>>       return _imread(*args, **kwargs)
>>     File "/home/ben/Programs/matplotlib/lib/matplotlib/image.py", line
>> 1218, in imread
>>       return handler(fd)
>> TypeError: PyCXX: Error creating object of type N2Py6ObjectE from (nil)
>>
>> Using master branch on Python 2.7 on 32-bit Ubuntu Oneric.  Seems to
>> happen to both color and b&w images.  scipy.ndimage.imread() still works
>> fine, though.
>>
>> Ben Root
> I get the same thing with master on 64-bit ubuntu natty, but not with
> v1.1.x.  Mike did quite a bit of work on src/_png.cpp between those two.
>    The most recent commit to that file is not causing the problem, but I
> have not tracked it down beyond that.
>
> Eric
>
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> Mar 27 - Feb 2
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-- 
Michael Droettboom
Science Software Branch
Space Telescope Science Institute
Baltimore, Maryland, USA

Re: [matplotlib-devel] imread() in master branch doesn't work

[Eric F. <ef...@ha...>]

Mike,

Git bisect showed that the problem was your merge commit bca1fb0; you 
were merging a changeset relative to a very old version, and I'm pretty 
sure that you accidentally kept the old version of a line.  I switched 
it back to the new version:

https://github.com/matplotlib/matplotlib/commit/c9cefdcf50742fd041636b20aa48d3a821d3299d

Maybe your suggested patch below is still a good idea, but I think that 
is now an independent question.

Eric


On 01/17/2012 05:37 AM, Michael Droettboom wrote:
> I can't confirm this on RHEL5 64-bit or Fedora 16 64-bit.
>
> Have you tried removing the build and installed directories and
> rebuilding from scratch?
>
> I'm shooting in the dark, but does the attached patch resolve your issue?
>
> diff --git a/src/_png.cpp b/src/_png.cpp
> index 9437c87..c17dec9 100644
> --- a/src/_png.cpp
> +++ b/src/_png.cpp
> @@ -553,7 +553,7 @@ _png_module::_read_png(const Py::Object&  py_fileobj,
> const b
>
>        if (PyErr_Occurred()) {
>            Py_DECREF((PyObject *)A);
> -        return NULL;
> +        throw Py::Exception();
>        } else {
>            return (PyObject *)A;
>
> Mike
>
> On 01/14/2012 04:51 PM, Eric Firing wrote:
>> On 01/14/2012 09:02 AM, Benjamin Root wrote:
>>> Tried using plt.imread() today on a PNG file, and I am getting this
>>> PyCXX error:
>>>
>>> Traceback (most recent call last):
>>>      File "<stdin>", line 1, in<module>
>>>      File "/home/ben/Programs/matplotlib/lib/matplotlib/pyplot.py", line
>>> 1746, in imread
>>>        return _imread(*args, **kwargs)
>>>      File "/home/ben/Programs/matplotlib/lib/matplotlib/image.py", line
>>> 1218, in imread
>>>        return handler(fd)
>>> TypeError: PyCXX: Error creating object of type N2Py6ObjectE from (nil)
>>>
>>> Using master branch on Python 2.7 on 32-bit Ubuntu Oneric.  Seems to
>>> happen to both color and b&w images.  scipy.ndimage.imread() still works
>>> fine, though.
>>>
>>> Ben Root
>> I get the same thing with master on 64-bit ubuntu natty, but not with
>> v1.1.x.  Mike did quite a bit of work on src/_png.cpp between those two.
>>     The most recent commit to that file is not causing the problem, but I
>> have not tracked it down beyond that.
>>
>> Eric
>>
>> ------------------------------------------------------------------------------
>> RSA(R) Conference 2012
>> Mar 27 - Feb 2
>> Save $400 by Jan. 27
>> Register now!
>> http://p.sf.net/sfu/rsa-sfdev2dev2
>> _______________________________________________
>> Matplotlib-devel mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
>
>

Re: [matplotlib-devel] imread() in master branch doesn't work

[Michael D. <md...@st...>]

Ah.  That explains why I couldn't reproduce it -- I didn't realize the 
issue had already been closed.

Mike

On 01/17/2012 12:53 PM, Eric Firing wrote:
> Mike,
>
> Git bisect showed that the problem was your merge commit bca1fb0; you
> were merging a changeset relative to a very old version, and I'm pretty
> sure that you accidentally kept the old version of a line.  I switched
> it back to the new version:
>
> https://github.com/matplotlib/matplotlib/commit/c9cefdcf50742fd041636b20aa48d3a821d3299d
>
> Maybe your suggested patch below is still a good idea, but I think that
> is now an independent question.
>
> Eric
>
>
> On 01/17/2012 05:37 AM, Michael Droettboom wrote:
>> I can't confirm this on RHEL5 64-bit or Fedora 16 64-bit.
>>
>> Have you tried removing the build and installed directories and
>> rebuilding from scratch?
>>
>> I'm shooting in the dark, but does the attached patch resolve your issue?
>>
>> diff --git a/src/_png.cpp b/src/_png.cpp
>> index 9437c87..c17dec9 100644
>> --- a/src/_png.cpp
>> +++ b/src/_png.cpp
>> @@ -553,7 +553,7 @@ _png_module::_read_png(const Py::Object&   py_fileobj,
>> const b
>>
>>         if (PyErr_Occurred()) {
>>             Py_DECREF((PyObject *)A);
>> -        return NULL;
>> +        throw Py::Exception();
>>         } else {
>>             return (PyObject *)A;
>>
>> Mike
>>
>> On 01/14/2012 04:51 PM, Eric Firing wrote:
>>> On 01/14/2012 09:02 AM, Benjamin Root wrote:
>>>> Tried using plt.imread() today on a PNG file, and I am getting this
>>>> PyCXX error:
>>>>
>>>> Traceback (most recent call last):
>>>>       File "<stdin>", line 1, in<module>
>>>>       File "/home/ben/Programs/matplotlib/lib/matplotlib/pyplot.py", line
>>>> 1746, in imread
>>>>         return _imread(*args, **kwargs)
>>>>       File "/home/ben/Programs/matplotlib/lib/matplotlib/image.py", line
>>>> 1218, in imread
>>>>         return handler(fd)
>>>> TypeError: PyCXX: Error creating object of type N2Py6ObjectE from (nil)
>>>>
>>>> Using master branch on Python 2.7 on 32-bit Ubuntu Oneric.  Seems to
>>>> happen to both color and b&w images.  scipy.ndimage.imread() still works
>>>> fine, though.
>>>>
>>>> Ben Root
>>> I get the same thing with master on 64-bit ubuntu natty, but not with
>>> v1.1.x.  Mike did quite a bit of work on src/_png.cpp between those two.
>>>      The most recent commit to that file is not causing the problem, but I
>>> have not tracked it down beyond that.
>>>
>>> Eric
>>>
>>> ------------------------------------------------------------------------------
>>> RSA(R) Conference 2012
>>> Mar 27 - Feb 2
>>> Save $400 by Jan. 27
>>> Register now!
>>> http://p.sf.net/sfu/rsa-sfdev2dev2
>>> _______________________________________________
>>> Matplotlib-devel mailing list
>>> Mat...@li...
>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
>>
>
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-- 
Michael Droettboom
Science Software Branch
Space Telescope Science Institute
Baltimore, Maryland, USA