Unhelpful error message for misspelled repository name: "invalid tar file"

[AaronWatters]

Novice users find this error message unhelpful, please improve it.

starting build for URL: https://github.com/abcdef/ghijk
fetching source at https://github.com/abcdef/ghijk
could not build image abcdef-ghijk: Error: invalid tar file

[freeman-lab]

Thanks for flagging, one option would be to do a client-side check that the repository exists on the website before even starting the build. We're currently doing that just to check for valid repository names, but not to check that it exists.

[minrk]

binder-project/binder-build#4 should give a better error when the repo download fails for any reason. The resulting 404 might at least point the user in the right direction.