Forbid nested ternary operations.

mesonbuild/mparser.py

@@ -353,6 +353,7 @@ class Parser:
     def __init__(self, code):
         self.stream = Lexer().lex(code)
         self.getsym()
+        self.in_ternary = False
 
     def getsym(self):
         try:
@@ -393,9 +394,14 @@ class Parser:
                                      left.lineno, left.colno)
             return AssignmentNode(left.lineno, left.colno, left.value, value)
         elif self.accept('questionmark'):
+            if self.in_ternary:
+                raise ParseException('Nested ternary operators are not allowed.',
+                                     left.lineno, left.colno)
+            self.in_ternary = True
             trueblock = self.e1()
             self.expect('colon')
             falseblock = self.e1()
+            self.in_ternary = False
             return TernaryNode(left.lineno, left.colno, left, trueblock, falseblock)
         return left
 

test cases/failing/30 nested ternary/meson.build

@@ -0,0 +1,3 @@
+project('nested ternary', 'c')
+
+x = true ? (false ? 1 : 0) : 2