BufferError
PythonERRORNotableRuntime ErrorHIGH confidence
Buffer operation failed
Production Risk
Occurs in high-performance code using memoryview and mutable buffers; always release views before mutation.
What this means
Raised when a buffer-related operation cannot be performed, typically because an object's buffer is locked by another operation or the requested buffer operation is not supported.
Why it happens
- 1Trying to resize a bytearray while a memoryview is active
- 2Attempting a buffer operation on an object that does not support the buffer protocol
How to reproduce
Resizing a bytearray while a memoryview holds a reference.
trigger — this will error
trigger — this will error
buf = bytearray(b'hello world') view = memoryview(buf) buf.extend(b' extra') # Raises BufferError
expected output
BufferError: Existing exports of data: object cannot be re-sized
Fix
Release the memoryview before modifying the buffer
WHEN Working with memoryview and mutable buffers
Release the memoryview before modifying the buffer
buf = bytearray(b'hello world') view = memoryview(buf) # Use view for read operations data = bytes(view[:5]) view.release() # Release memoryview first buf.extend(b' extra') # Now safe to resize
Why this works
memoryview.release() drops the reference to the buffer, allowing the underlying bytearray to be resized.
Code examples
Triggerpython
buf = bytearray(b"hello") view = memoryview(buf) buf.extend(b" world") # BufferError: object cannot be re-sized
Handle with try/exceptpython
try:
buf.extend(extra)
except BufferError:
view.release()
buf.extend(extra)Avoid by releasing memoryview firstpython
view = memoryview(buf) data = bytes(view) # copy data out view.release() # release lock buf.extend(extra) # now safe
Same error in other languages
Sources
Official documentation ↗
Python Docs — Built-in Exceptions
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