Recursive Item Mapping for Nested Lists in Compose

[KumoLiu]

Fixes #8186.

Description

A few sentences describing the changes proposed in this pull request.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[ziw-liu]

Hi @KumoLiu and thanks for the fix! Is this branch ready for testing?

[KumoLiu]

Hi @KumoLiu and thanks for the fix! Is this branch ready for testing?

Hi @ziw-liu, the current fix solves the problem you raised, but it leads to something else, such as not having a handle for those who don't want a recursive map. I still need to revise this PR further. Thanks.

[ericspod]

@atbenmurray please review this as well as we just discussed.

[atbenmurray]

Looking at it, map_items=True has always acted as map_items=1, so at least we aren't changing the behaviour of using bool and now the int indicates the maximum amount of nesting that can be expected. This would also be the case if we use a multi sample transform after a multi sample transform. Its a bit opaque semantically that we do this and might benefit from additional commenting.

[KumoLiu]

Hi @atbenmurray, thanks for the suggestion, I enhance the docstring in the latest commit. Please help take a look whether it looks clearer to you.

[atbenmurray]

minor tweak required due to a typo in my earlier suggestion

[atbenmurray]

Happy with these comments!