Issue Kind

Change in current behaviour

Description

When the tool.poetry.source section in pyproject.toml is provided as a [single table] rather than [[array of tables]] the error poetry provides isn't very helpful:

The Poetry configuration is invalid:
  - data.source must be array

A more descriptive error and/or a reference to what section or line in the toml would be a little more friendly. Tried this with -vvv and the stack trace also doesn't give a clue to what part of the toml is actually the problem.

A more broad way to phrase it, if you like, might be "toml structure errors should report a line or section if possible"

Impact

Some more info in the error would make troubleshooting faster; as it is one either 'just knows' the expected structure or goes section by section, which might be slower or faster depending on the size of pyproject.toml.

Workarounds

None that I'm aware of