Migration to V4 protocol version fail

[lleleux]

Hi,

When I try to migrate from v3 to v4, I have this error :

I'm on Ubuntu 20.10, and my /home is on another partition than /tmp.

I asked to write the new version to /tmp, and it worked. But I have the same problem when I copy the protocol to my /home, update it, and try to save it.

As a workaround, I work on another partition for the moment.

Thank you for your work.

Laurent

[lleleux]

If I'm not wrong, you are using the "rename" function to move the file from /tmp to the new location. But I think it doesn't work cross partitions. You need maybe to copy and then unlink the file.

If this can help you ;-)

[jthrilly]

Thanks @lleleux! You're almost certainly right about the root cause. We had a bit of an internal discussion about "renaming" vs "moving" (where moving is first copying and then unlinking). It seems there is in fact a difference between the two.

Thank you for catching this. A fix will be coming as soon as we are all back in the office.

[wwqrd]

This might also explain some of the issues with the snap packages (which are sand-boxed with their own virtual /tmp/ dir), since protocols are created in the temp dir before being renamed to user space.

[wwqrd]

Should be resolved by #691 which changes the rename method to copy