On armv7hl, some get_cursor_data calls return 0 instead of None.

[rathann]

To help us understand and resolve your issue please check that you have provided
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• Matplotlib version, Python version and Platform (Windows, OSX, Linux ...)

1.5.2rc2, 2.7.11/3.5.1, Fedora rawhide

• How did you install Matplotlib and Python (pip, anaconda, from source ...)

From source (building a new version of Fedora package).

• If possible please supply a Short, Self Contained, Correct, Example
  that demonstrates the issue i.e a small piece of code which reproduces the issue
  and can be run with out any other (or as few as possible) external dependencies.

The following three tests fail due to get_cursor_data() calls returning 0 instead of None.

diff -up matplotlib-1.5.1/lib/matplotlib/tests/test_image.py.tests matplotlib-1.5.1/lib/matplotlib/tests/test_image.py
--- matplotlib-1.5.1/lib/matplotlib/tests/test_image.py.tests   2016-05-23 14:04:41.000000000 +0200
+++ matplotlib-1.5.1/lib/matplotlib/tests/test_image.py 2016-06-02 00:28:37.076703843 +0200
@@ -186,7 +186,8 @@ def test_cursor_data():

     event = MouseEvent('motion_notify_event', fig.canvas, xdisp, ydisp)
     z = im.get_cursor_data(event)
-    assert z is None, "Did not get None, got %d" % z
+    #0 instead of None on armv7hl
+    #assert z is None, "Did not get None, got %d" % z

     # Hmm, something is wrong here... I get 0, not None...
     # But, this works further down in the tests with extents flipped
@@ -224,14 +225,16 @@ def test_cursor_data():

     event = MouseEvent('motion_notify_event', fig.canvas, xdisp, ydisp)
     z = im.get_cursor_data(event)
-    assert z is None, "Did not get None, got %d" % z
+    #0 instead of None on armv7hl
+    #assert z is None, "Did not get None, got %d" % z

     x, y = 0.01, -0.01
     xdisp, ydisp = ax.transData.transform_point([x, y])

     event = MouseEvent('motion_notify_event', fig.canvas, xdisp, ydisp)
     z = im.get_cursor_data(event)
-    assert z is None, "Did not get None, got %d" % z
+    #0 instead of None on armv7hl
+    #assert z is None, "Did not get None, got %d" % z


 @image_comparison(baseline_images=['image_clip'])

[tacaswell]

We see this from the debian build on arm as well.

[tacaswell]

re-milestoned, this is not a blocking issue for 2.0

[rathann]

FYI, this is reproducible with 2.0.0b4 on armv7hl (ARMv7 HFP) and aarch64 (ARM v8) as well.

[tacaswell]

#9304 has a patch for this.