Add unclosed group to grammar

devRD · ksunden · devRD · commit 57fda4f14012 · 2023-08-15T15:57:56.000+05:30
Co-authored-by: Kyle Sunden &lt;git@ksunden.space&gt;
diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
@@ -1865,6 +1865,8 @@ def csnames(group, names):
                 "|".join(map(re.escape, tex2uni)))
         )("sym").leaveWhitespace()
         p.unknown_symbol = Regex(r"\\[A-Za-z]+")("name")
+        def unclosed_group(self, s, loc, toks):
+            raise ParseFatalException(s, len(s), "Expected '}'")
 
         p.font           = csnames("font", self._fontnames)
         p.start_group    = Optional(r"\math" + oneOf(self._fontnames)("font")) + "{"
@@ -1894,6 +1896,7 @@ def csnames(group, names):
         p.function = csnames("name", self._function_names)
 
         p.group = p.start_group + ZeroOrMore(p.token)("group") + p.end_group
+        p.unclosed_group = (p.start_group + ZeroOrMore(p.token)("group") + StringEnd())
 
         p.frac  = cmd(r"\frac", p.required_group("num") + p.required_group("den"))
         p.dfrac = cmd(r"\dfrac", p.required_group("num") + p.required_group("den"))
@@ -1942,6 +1945,7 @@ def csnames(group, names):
         p.token <<= (
             p.simple
             | p.auto_delim
+            | p.unclosed_group
             | p.unknown_symbol  # Must be last
         )
 
@@ -2145,6 +2149,9 @@ def symbol(self, s, loc, toks):
     def unknown_symbol(self, s, loc, toks):
         raise ParseFatalException(s, loc, f"Unknown symbol: {toks['name']}")
 
+    def unclosed_group(self, s, loc, toks):
+        raise ParseFatalException(s, len(s), "Expected '}'")
+
     _accent_map = {
         r'hat':            r'\circumflexaccent',
         r'breve':          r'\combiningbreve',
diff --git a/lib/matplotlib/tests/test_mathtext.py b/lib/matplotlib/tests/test_mathtext.py
@@ -320,7 +320,7 @@ def test_fontinfo():
         (r'$a^2^2$', r'Double superscript'),
         (r'$a_2_2$', r'Double subscript'),
         (r'$a^2_a^2$', r'Double superscript'),
-        (r'$a = {b$', r'Expected end of text'),
+        (r'$a = {b$', r"Expected '}'"),
     ],
     ids=[
         'hspace without value',
@@ -349,7 +349,7 @@ def test_fontinfo():
         'double superscript',
         'double subscript',
         'super on sub without braces',
-        'math string with no closing braces'
+        'unclosed group'
     ]
 )
 def test_mathtext_exceptions(math, msg):
