[BrandonY]

Hi, GCS engineer here. The lower limit on composing objects is one source object, in which case you are not so much composing as you are copying with style. Zero source objects is an error. I will file a note about the docs, thanks.

[toomuchtodo]

Thank you so much! Is there a limit on size of objects besides the 5TB max described in the docs, similar to other object stores where multiparts have lower limits than the total composed object?

[BrandonY]

There is also a lower bound of 0 bytes :)

You can compose a 4TB object with a 1 byte object, or you can compose 32 150GB objects, just so long as the destination object doesn't go over 5 terabytes.

[toomuchtodo]

Brilliant! Thank you again!