Deprecate the TTFPATH & AFMPATH environment variables.

anntzer · anntzer · commit e8559db02def · 2020-01-09T17:21:56.000+01:00
These undocumented environment variables allow one to selectively add
paths to the font cache... but only if the font cache doesn't exist yet
(they don't force cache regen).  The font-cache regen API (_rebuild())
is also private (even though one can trigger it "publically" e.g. by
calling `findfont` with a nonexisting font...).

Instead, we now expose `addfont()` which is a documented API for
registering fonts with the font manager.
diff --git a/doc/api/next_api_changes/deprecations.rst b/doc/api/next_api_changes/deprecations.rst
@@ -131,3 +131,9 @@ This method is deprecated.  Use
 ``SymmetricalScale.SymmetricalTransform`` and
 ``SymmetricalScale.InvertedSymmetricalTransform`` are deprecated.  Directly
 access the transform classes from the :mod:`.scale` module.
+
+The ``TTFPATH`` and ``AFMPATH`` environment variables
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Support for the (undocumented) ``TTFPATH`` and ``AFMPATH`` environment
+variables is deprecated.  Additional fonts may be registered using
+``matplotlib.font_manager.fontManager.addfont()``.
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -971,6 +971,9 @@ def __init__(self, size=None, weight='normal'):
                     paths.extend(ttfpath.split(':'))
                 else:
                     paths.append(ttfpath)
+                cbook.warn_deprecated(
+                    "3.3", name=pathname, obj_type="environment variable",
+                    alternative="FontManager.addfont()")
         _log.debug('font search path %s', str(paths))
         #  Load TrueType fonts and create font dictionary.
 
