写方法中的“预期类型'Union [str，bytearray]'取为'int'”警告

Question

我的脚本使用预先生成的数据模式逐块写入文件：

#  Data pattern generator    
def get_random_chunk_pattern():
            return ''.join(random.choice(ascii_uppercase + digits + ascii_lowercase) for _ in range(8))

....

# DedupChunk class CTOR:
class DedupChunk:
    def __init__(self, chunk_size, chunk_pattern, chunk_position=0, state=DedupChunkStates.PENDING):
        self._chunk_size = chunk_size  # chunk size in bytes
        self._chunk_pattern = chunk_pattern
        self._chunk_position = chunk_position
        self._state = state
        self.mapping = None

    @property
    def size(self):
        return self._chunk_size

    @property
    def pattern(self):
        return self._chunk_pattern

    @property
    def position(self):
        return self._chunk_position

    @property
    def state(self):
        return self._state

....

# Here Chunk object is being initialized (inside other class's CTOR):
chunk_size = random.randint(64, 192) * 1024  # in bytes
        while (position + chunk_size) < self.file_size:  # generating random chunks number
            self.chunks.append(DedupChunk(chunk_size, DedupChunkPattern.get_random_chunk_pattern(), position))

....

# Actual writing
    with open(self.path, 'rb+') as f:
        for chunk in self.chunks:
            f.write(chunk.pattern * (chunk.size // 8))

PyCharm``Expected type 'Union[str, bytearray]' got 'int' instead在写入方法中显示警告

但是，在中删除 f.write(chunk.pattern * chunk.size)或在外面进行除法时：

chunk.size //= 8
f.write(chunk.pattern * chunk.size)

警告消失

这里到底发生了什么？

谢谢

Answer 1

忽略此警告。IDE会（根据有限的信息）对运行时的数据类型进行最佳猜测，但猜测是错误的。也就是说，如果您不知道某物实际上是什么，可以期望乘以某物int会导致一个结果int。

如果您真的想解决此问题，请chunk.pattern通过为类编写文档字符串（或使用批注提供类型提示）来告诉IDE您期望什么。

例如。

class DedupChunk:
    """
    :type _chunk_pattern: str
    ... other fields
    """
    ... # rest of class