matplotlib · anntzer · Jun 10, 2017 · Jun 2, 2017 · Jun 3, 2017 · Jun 3, 2017
diff --git a/doc/api/api_changes/2017-06-03-ES_unique_renderer.rst b/doc/api/api_changes/2017-06-03-ES_unique_renderer.rst
@@ -0,0 +1,11 @@
+Unique identifier added to `RendererBase` classes
+`````````````````````````````````````````````````
+
+Since ``id()`` is not guaranteed to be unique between objects that exist at
+different times, a new private property ``_uid`` has been added to
+`RendererBase` which is used along with the renderer's ``id()`` to cache
+certain expensive operations.
+
+If a custom renderer does not subclass `RendererBase` or `MixedModeRenderer`,
+it is not required to implement this ``_uid`` property, but this may produce
+incorrect behavior when the renderers' ``id()`` clashes.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -41,6 +41,7 @@
 from contextlib import contextmanager
 import importlib
 import io
+import itertools
 import os
 import sys
 import time
@@ -100,6 +101,12 @@
 }
 
 
+# Used to ensure that caching based on renderer id() is unique without being as
+# expensive as a real UUID. 0 is used for renderers that don't derive from
+# here, so start at 1.
+_unique_renderer_id = itertools.count(1)
+
+
 def register_backend(format, backend, description=None):
     """
     Register a backend for saving to a given file format.
@@ -212,6 +219,10 @@ class RendererBase(object):
 
     """
     def __init__(self):
+        # A lightweight id for unique-ification purposes. Along with id(self),
+        # the combination should be unique enough to use as part of a cache key.
+        self._uid = next(_unique_renderer_id)
+
         self._texmanager = None
 
         self._text2path = textpath.TextToPath()

diff --git a/lib/matplotlib/backends/backend_mixed.py b/lib/matplotlib/backends/backend_mixed.py
@@ -5,6 +5,7 @@
 
 import six
 
+import matplotlib.backend_bases
 from matplotlib.backends.backend_agg import RendererAgg
 from matplotlib.tight_bbox import process_figure_for_rasterizing
 
@@ -49,6 +50,9 @@ def __init__(self, figure, width, height, dpi, vector_renderer,
         if raster_renderer_class is None:
             raster_renderer_class = RendererAgg
 
+        # See matplotlib.backend_bases.RendererBase._uid.
+        self._uid = next(matplotlib.backend_bases._unique_renderer_id)
+
         self._raster_renderer_class = raster_renderer_class
         self._width = width
         self._height = height

diff --git a/lib/matplotlib/tests/test_backend_pdf.py b/lib/matplotlib/tests/test_backend_pdf.py
@@ -178,6 +178,8 @@ def test_grayscale_alpha():
     ax.set_yticks([])
 
 
+# This tests tends to hit a TeX cache lock on AppVeyor.
+@pytest.mark.flaky(reruns=3)
 @needs_tex
 def test_missing_psfont(monkeypatch):
     """An error is raised if a TeX font lacks a Type-1 equivalent"""

diff --git a/lib/matplotlib/tests/test_backend_ps.py b/lib/matplotlib/tests/test_backend_ps.py
@@ -27,6 +27,8 @@
     reason="This test needs a TeX installation")
 
 
+# This tests tends to hit a TeX cache lock on AppVeyor.
+@pytest.mark.flaky(reruns=3)
 @pytest.mark.parametrize('format, use_log, rcParams', [
     ('ps', False, {}),
     needs_ghostscript(('ps', False, {'ps.usedistiller': 'ghostscript'})),

diff --git a/lib/matplotlib/tests/test_mathtext.py b/lib/matplotlib/tests/test_mathtext.py
@@ -167,9 +167,6 @@ def baseline_images(request, fontset, index):
     return ['%s_%s_%02d' % (request.param, fontset, index)]
 
 
-# See #7911 for why these tests are flaky and #7107 for why they are not so
-# easy to fix.
-@pytest.mark.flaky(reruns=3)
 @pytest.mark.parametrize('index, test', enumerate(math_tests),
                          ids=[str(index) for index in range(len(math_tests))])
 @pytest.mark.parametrize('fontset',
@@ -184,9 +181,6 @@ def test_mathtext_rendering(baseline_images, fontset, index, test):
              horizontalalignment='center', verticalalignment='center')
 
 
-# See #7911 for why these tests are flaky and #7107 for why they are not so
-# easy to fix.
-@pytest.mark.flaky(reruns=3)
 @pytest.mark.parametrize('index, test', enumerate(font_tests),
                          ids=[str(index) for index in range(len(font_tests))])
 @pytest.mark.parametrize('fontset',

diff --git a/lib/matplotlib/tests/test_tightlayout.py b/lib/matplotlib/tests/test_tightlayout.py
@@ -58,7 +58,7 @@ def test_tight_layout3():
 
 
 @image_comparison(baseline_images=['tight_layout4'],
-                  freetype_version=('2.4.5', '2.4.9'))
+                  freetype_version=('2.5.5', '2.6.1'))
 def test_tight_layout4():
     'Test tight_layout for subplot2grid'
 

diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -907,11 +907,12 @@ def get_prop_tup(self, renderer=None):
         need to know if the text has changed.
         """
         x, y = self.get_unitless_position()
+        renderer = renderer or self._renderer
         return (x, y, self.get_text(), self._color,
                 self._verticalalignment, self._horizontalalignment,
                 hash(self._fontproperties),
                 self._rotation, self._rotation_mode,
-                self.figure.dpi, id(renderer or self._renderer),
+                self.figure.dpi, id(renderer), getattr(renderer, '_uid', 0),
                 self._linespacing
                 )