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authornkozlovskiy <nmk@ydb.tech>2023-09-29 12:24:06 +0300
committernkozlovskiy <nmk@ydb.tech>2023-09-29 12:41:34 +0300
commite0e3e1717e3d33762ce61950504f9637a6e669ed (patch)
treebca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/python/pytest/py3/_pytest/mark/expression.py
parent38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff)
downloadydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz
add ydb deps
Diffstat (limited to 'contrib/python/pytest/py3/_pytest/mark/expression.py')
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+r"""Evaluate match expressions, as used by `-k` and `-m`.
+
+The grammar is:
+
+expression: expr? EOF
+expr: and_expr ('or' and_expr)*
+and_expr: not_expr ('and' not_expr)*
+not_expr: 'not' not_expr | '(' expr ')' | ident
+ident: (\w|:|\+|-|\.|\[|\]|\\|/)+
+
+The semantics are:
+
+- Empty expression evaluates to False.
+- ident evaluates to True of False according to a provided matcher function.
+- or/and/not evaluate according to the usual boolean semantics.
+"""
+import ast
+import dataclasses
+import enum
+import re
+import sys
+import types
+from typing import Callable
+from typing import Iterator
+from typing import Mapping
+from typing import NoReturn
+from typing import Optional
+from typing import Sequence
+
+if sys.version_info >= (3, 8):
+ astNameConstant = ast.Constant
+else:
+ astNameConstant = ast.NameConstant
+
+
+__all__ = [
+ "Expression",
+ "ParseError",
+]
+
+
+class TokenType(enum.Enum):
+ LPAREN = "left parenthesis"
+ RPAREN = "right parenthesis"
+ OR = "or"
+ AND = "and"
+ NOT = "not"
+ IDENT = "identifier"
+ EOF = "end of input"
+
+
+@dataclasses.dataclass(frozen=True)
+class Token:
+ __slots__ = ("type", "value", "pos")
+ type: TokenType
+ value: str
+ pos: int
+
+
+class ParseError(Exception):
+ """The expression contains invalid syntax.
+
+ :param column: The column in the line where the error occurred (1-based).
+ :param message: A description of the error.
+ """
+
+ def __init__(self, column: int, message: str) -> None:
+ self.column = column
+ self.message = message
+
+ def __str__(self) -> str:
+ return f"at column {self.column}: {self.message}"
+
+
+class Scanner:
+ __slots__ = ("tokens", "current")
+
+ def __init__(self, input: str) -> None:
+ self.tokens = self.lex(input)
+ self.current = next(self.tokens)
+
+ def lex(self, input: str) -> Iterator[Token]:
+ pos = 0
+ while pos < len(input):
+ if input[pos] in (" ", "\t"):
+ pos += 1
+ elif input[pos] == "(":
+ yield Token(TokenType.LPAREN, "(", pos)
+ pos += 1
+ elif input[pos] == ")":
+ yield Token(TokenType.RPAREN, ")", pos)
+ pos += 1
+ else:
+ match = re.match(r"(:?\w|:|\+|-|\.|\[|\]|\\|/)+", input[pos:])
+ if match:
+ value = match.group(0)
+ if value == "or":
+ yield Token(TokenType.OR, value, pos)
+ elif value == "and":
+ yield Token(TokenType.AND, value, pos)
+ elif value == "not":
+ yield Token(TokenType.NOT, value, pos)
+ else:
+ yield Token(TokenType.IDENT, value, pos)
+ pos += len(value)
+ else:
+ raise ParseError(
+ pos + 1,
+ f'unexpected character "{input[pos]}"',
+ )
+ yield Token(TokenType.EOF, "", pos)
+
+ def accept(self, type: TokenType, *, reject: bool = False) -> Optional[Token]:
+ if self.current.type is type:
+ token = self.current
+ if token.type is not TokenType.EOF:
+ self.current = next(self.tokens)
+ return token
+ if reject:
+ self.reject((type,))
+ return None
+
+ def reject(self, expected: Sequence[TokenType]) -> NoReturn:
+ raise ParseError(
+ self.current.pos + 1,
+ "expected {}; got {}".format(
+ " OR ".join(type.value for type in expected),
+ self.current.type.value,
+ ),
+ )
+
+
+# True, False and None are legal match expression identifiers,
+# but illegal as Python identifiers. To fix this, this prefix
+# is added to identifiers in the conversion to Python AST.
+IDENT_PREFIX = "$"
+
+
+def expression(s: Scanner) -> ast.Expression:
+ if s.accept(TokenType.EOF):
+ ret: ast.expr = astNameConstant(False)
+ else:
+ ret = expr(s)
+ s.accept(TokenType.EOF, reject=True)
+ return ast.fix_missing_locations(ast.Expression(ret))
+
+
+def expr(s: Scanner) -> ast.expr:
+ ret = and_expr(s)
+ while s.accept(TokenType.OR):
+ rhs = and_expr(s)
+ ret = ast.BoolOp(ast.Or(), [ret, rhs])
+ return ret
+
+
+def and_expr(s: Scanner) -> ast.expr:
+ ret = not_expr(s)
+ while s.accept(TokenType.AND):
+ rhs = not_expr(s)
+ ret = ast.BoolOp(ast.And(), [ret, rhs])
+ return ret
+
+
+def not_expr(s: Scanner) -> ast.expr:
+ if s.accept(TokenType.NOT):
+ return ast.UnaryOp(ast.Not(), not_expr(s))
+ if s.accept(TokenType.LPAREN):
+ ret = expr(s)
+ s.accept(TokenType.RPAREN, reject=True)
+ return ret
+ ident = s.accept(TokenType.IDENT)
+ if ident:
+ return ast.Name(IDENT_PREFIX + ident.value, ast.Load())
+ s.reject((TokenType.NOT, TokenType.LPAREN, TokenType.IDENT))
+
+
+class MatcherAdapter(Mapping[str, bool]):
+ """Adapts a matcher function to a locals mapping as required by eval()."""
+
+ def __init__(self, matcher: Callable[[str], bool]) -> None:
+ self.matcher = matcher
+
+ def __getitem__(self, key: str) -> bool:
+ return self.matcher(key[len(IDENT_PREFIX) :])
+
+ def __iter__(self) -> Iterator[str]:
+ raise NotImplementedError()
+
+ def __len__(self) -> int:
+ raise NotImplementedError()
+
+
+class Expression:
+ """A compiled match expression as used by -k and -m.
+
+ The expression can be evaluated against different matchers.
+ """
+
+ __slots__ = ("code",)
+
+ def __init__(self, code: types.CodeType) -> None:
+ self.code = code
+
+ @classmethod
+ def compile(self, input: str) -> "Expression":
+ """Compile a match expression.
+
+ :param input: The input expression - one line.
+ """
+ astexpr = expression(Scanner(input))
+ code: types.CodeType = compile(
+ astexpr,
+ filename="<pytest match expression>",
+ mode="eval",
+ )
+ return Expression(code)
+
+ def evaluate(self, matcher: Callable[[str], bool]) -> bool:
+ """Evaluate the match expression.
+
+ :param matcher:
+ Given an identifier, should return whether it matches or not.
+ Should be prepared to handle arbitrary strings as input.
+
+ :returns: Whether the expression matches or not.
+ """
+ ret: bool = eval(self.code, {"__builtins__": {}}, MatcherAdapter(matcher))
+ return ret