export doesn't allow overwriting current document (?)

[Noel Grandin]

On 2019/02/07 2:28 PM, Caolán McNamara wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1673198 points out that if
> you import a pdf document and then try and re-export that pdf to
> overwrite the original, the overwrite is not allowed. (Though there is
> no such general problem with save/save-as to overwrite the original
> document)
> 

Given how we cache and re-read external stuff like images, perhaps at one point in time, we could end up reading from 
the same file that we are writing to during the export process?

Which depending on the order of the operations, is a bug that might only show up on an OS like Windows, which does not 
have an inode-based filesystem.