8000 Simplify and tighten parse_fontconfig_pattern. · matplotlib/matplotlib@c216c09 · GitHub
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Simplify and tighten parse_fontconfig_pattern.
- Warn on unknown constant names, e.g. ``DejaVu Sans:unknown`` (as opposed e.g. to ``DejaVu Sans:bold``); they were previously silently ignored. - Rewrite the parser into something much simpler, moving nearly all the logic into a single block post-processing the result of parseString, instead of splitting everything into many small parse actions. In particular this makes the parser mostly stateless (except for the cache held by pyparsing itself), instead of having the various parts communicate through the _properties attribute.
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-92
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‎doc/api/next_api_changes/deprecations/24220-AL.rst

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@@ -0,0 +1,5 @@
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``parse_fontconfig_pattern`` will no longer ignore unknown constant names
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Previously, in a fontconfig pattern like ``DejaVu Sans:foo``, the unknown
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``foo`` constant name would be silently ignored. This now raises a warning,
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and will become an error in the future.

‎lib/matplotlib/_fontconfig_pattern.py

Lines changed: 45 additions & 91 deletions
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@@ -9,22 +9,29 @@
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# there would have created cyclical dependency problems, because it also needs
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# to be available from `matplotlib.rcsetup` (for parsing matplotlibrc files).
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12-
from functools import lru_cache
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from functools import lru_cache, partial
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import re
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1515
import numpy as np
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from pyparsing import (
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Literal, Optional, ParseException, Regex, StringEnd, Suppress, ZeroOrMore,
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)
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Optional, ParseException, Regex, StringEnd, Suppress, ZeroOrMore)
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19+
from matplotlib import _api
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1921

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family_punc = r'\\\-:,'
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family_unescape = re.compile(r'\\([%s])' % family_punc).sub
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_family_unescape = partial(re.compile(r'\\(?=[%s])' % family_punc).sub, '')
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family_escape = re.compile(r'([%s])' % family_punc).sub
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value_punc = r'\\=_:,'
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value_unescape = re.compile(r'\\([%s])' % value_punc).sub
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_value_unescape = partial(re.compile(r'\\(?=[%s])' % value_punc).sub, '')
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value_escape = re.compile(r'([%s])' % value_punc).sub
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# Remove after module deprecation elapses (3.8); then remove underscores
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# from _family_unescape and _value_unescape.
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family_unescape = re.compile(r'\\([%s])' % family_punc).sub
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value_unescape = re.compile(r'\\([%s])' % value_punc).sub
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class FontconfigPatternParser:
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"""
@@ -58,63 +65,27 @@ class FontconfigPatternParser:
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'semicondensed': ('width', 'semi-condensed'),
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'expanded': ('width', 'expanded'),
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'extraexpanded': ('width', 'extra-expanded'),
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'ultraexpanded': ('width', 'ultra-expanded')
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}
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'ultraexpanded': ('width', 'ultra-expanded'),
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}
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def __init__(self):
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family = Regex(
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r'([^%s]|(\\[%s]))*' % (family_punc, family_punc)
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).setParseAction(self._family)
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size = Regex(
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r"([0-9]+\.?[0-9]*|\.[0-9]+)"
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).setParseAction(self._size)
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name = Regex(
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r'[a-z]+'
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).setParseAction(self._name)
77-
78-
value = Regex(
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r'([^%s]|(\\[%s]))*' % (value_punc, value_punc)
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).setParseAction(self._value)
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82-
families = (
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family
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+ ZeroOrMore(
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Literal(',')
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+ family)
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).setParseAction(self._families)
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point_sizes = (
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size
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+ ZeroOrMore(
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Literal(',')
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+ size)
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).setParseAction(self._point_sizes)
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property = (
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(name
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+ Suppress(Literal('='))
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+ value
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+ ZeroOrMore(
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Suppress(Literal(','))
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+ value))
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| name
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).setParseAction(self._property)
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def comma_separated(elem):
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return elem + ZeroOrMore(Suppress(",") + elem)
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family = Regex(r"([^%s]|(\\[%s]))*" % (family_punc, family_punc))
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size = Regex(r"([0-9]+\.?[0-9]*|\.[0-9]+)")
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name = Regex(r"[a-z]+")
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value = Regex(r"([^%s]|(\\[%s]))*" % (value_punc, value_punc))
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prop = (
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(name + Suppress("=") + comma_separated(value))
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| name # replace by oneOf(self._constants) in mpl 3.9.
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)
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pattern = (
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Optional(
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families)
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+ Optional(
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Literal('-')
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+ point_sizes)
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+ ZeroOrMore(
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Literal(':')
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+ property)
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Optional(comma_separated(family)("families"))
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+ Optional("-" + comma_separated(size)("sizes"))
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+ ZeroOrMore(":" + prop("properties*"))
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+ StringEnd()
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)
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self._parser = pattern
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self.ParseException = ParseException
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@@ -124,47 +95,30 @@ def parse(self, pattern):
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of key/value pairs useful for initializing a
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`.font_manager.FontProperties` object.
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"""
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props = self._properties = {}
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try:
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self._parser.parseString(pattern)
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parse = self._parser.parseString(pattern)
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except ParseException as err:
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# explain becomes a plain method on pyparsing 3 (err.explain(0)).
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raise ValueError("\n" + ParseException.explain(err, 0)) from None
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self._properties = None
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self._parser.resetCache()
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props = {}
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if "families" in parse:
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props["family"] = [*map(_family_unescape, parse["families"])]
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if "sizes" in parse:
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props["size"] = [*parse["sizes"]]
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for prop in parse.get("properties", []):
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if len(prop) == 1:
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if prop[0] not in self._constants:
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_api.warn_deprecated(
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"3.7", message=f"Support for unknown constants "
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f"({prop[0]!r}) is deprecated since %(since)s and "
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f"will be removed %(removal)s.")
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continue
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prop = self._constants[prop[0]]
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k, *v = prop
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props.setdefault(k, []).extend(map(_value_unescape, v))
135120
return props
136121

137-
def _family(self, s, loc, tokens):
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return [family_unescape(r'\1', str(tokens[0]))]
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def _size(self, s, loc, tokens):
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return [float(tokens[0])]
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def _name(self, s, loc, tokens):
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return [str(tokens[0])]
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def _value(self, s, loc, tokens):
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return [value_unescape(r'\1', str(tokens[0]))]
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def _families(self, s, loc, tokens):
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self._properties['family'] = [str(x) for x in tokens]
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return []
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def _point_sizes(self, s, loc, tokens):
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self._properties['size'] = [str(x) for x in tokens]
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return []
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157-
def _property(self, s, loc, tokens):
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if len(tokens) == 1:
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if tokens[0] in self._constants:
160-
key, val = self._constants[tokens[0]]
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self._properties.setdefault(key, []).append(val)
162-
else:
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key = tokens[0]
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val = tokens[1:]
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self._properties.setdefault(key, []).extend(val)
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return []
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169123
# `parse_fontconfig_pattern` is a bottleneck during the tests because it is
170124
# repeatedly called when the rcParams are reset (to validate the default

‎lib/matplotlib/tests/test_fontconfig_pattern.py

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,5 @@
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import pytest
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from matplotlib.font_manager import FontProperties
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35

@@ -60,11 +62,16 @@ def test_fontconfig_str():
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assert getattr(font, k)() == getattr(right, k)(), test + k
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6264
test = "full "
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s = ("serif:size=24:style=oblique:variant=small-caps:weight=bold"
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s = ("serif-24:style=oblique:variant=small-caps:weight=bold"
6466
":stretch=expanded")
6567
font = FontProperties(s)
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right = FontProperties(family="serif", size=24, weight="bold",
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style="oblique", variant="small-caps",
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stretch="expanded")
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for k in keys:
7072
assert getattr(font, k)() == getattr(right, k)(), test + k
73+
74+
75+
def test_fontconfig_unknown_constant():
76+
with pytest.warns(DeprecationWarning):
77+
FontProperties(":unknown")

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