External materialization fails if table is empty

[guenp]

When using an external materializations (external.sql), one of the first steps is to write the table to an external file:

copy "memory"."foo"."table_json__dbt_tmp" to '/foo/bar/baz/table_json.json' (format json)

if the model is empty, this should create an empty file.

this works locally, however, when using a remote location on s3://... the SQL command fails silently, and a remote file is not created.
This causes for the next step in the macro (creating a view) to fail with a 404 error:

Runtime Error in model table_json (models/table_json.sql)
HTTP Error: Unable to connect to URL "https:/my_bucket/table_json.json": 404 (Not Found)