SAM Build: path is on mount 'D:', start on mount 'C:'

[JadenSimon]

A toolkit user was having issues with SAM build when the target build directory and the code were on different drives (see aws/aws-toolkit-vscode#2296). By default the toolkit will create a temporary directory to build in which happened to be on a different drive, so the solution was to manually specify one on the same drive.

The failure occurs here:

aws-sam-cli/samcli/commands/_utils/template.py

Line 233 in ec9f5d8

return os.path.relpath(

Is this an edge-case for windows machines that needs to be looked into? From what I understand relative paths between drives are impossible so cross-drive resolution would just always fail here.

[wchengru]

Thanks for reporting this. One possible solution is to use the absolute path instead of relative one in this case. We will investigate how to resolve it.

[shearn89]

This error also appears to occur when working from a network drive that has been mapped: in my case, I have a directory mapped from a network share as Drive H, and I get:

ValueError: path is on mount 'H:', start on mount '\\\\servername\\fsname'

I can work around it by copying the repo to C:.