11282.breaking.rst

Sanitized the handling of the default parameter when defining configuration options.

Previously if default was not supplied for parser.addini <pytest.Parser.addini> and the configuration option value was not defined in a test session, then calls to config.getini <pytest.Config.getini> returned an empty list or an empty string depending on whether type was supplied or not respectively, which is clearly incorrect. Also, None was not honored even if default=None was used explicitly while defining the option.

Now the behavior of parser.addini <pytest.Parser.addini> is as follows:

• If default is NOT passed but type is provided, then a type-specific default will be returned. For example type=bool will return False, type=str will return "", etc.
• If default=None is passed and the option is not defined in a test session, then None will be returned, regardless of the type.
• If neither default nor type are provided, assume type=str and return "" as default (this is as per previous behavior).

The team decided to not introduce a deprecation period for this change, as doing so would be complicated both in terms of communicating this to the community as well as implementing it, and also because the team believes this change should not break existing plugins except in rare cases.