The initial implementation (in #7246) introduced the `importlib` mode, which
never added the imported module to `sys.modules`, so it included a test
to ensure calling `import_path` twice would yield different modules.
Not adding modules to `sys.modules` proved problematic, so we began to add the imported module to `sys.modules`
in #7870, but failed to realize that given we are now changing `sys.modules`, we might
as well avoid importing it more than once.
Then #10088 came along, passing `importlib` also when importing application modules
(as opposed to only test modules before), which caused problems due to imports
having side-effects and the expectation being that they are imported only once.
With this PR, `import_path` returns the module immediately if already in
`sys.modules`.
Fix#10811Fix#10341
Bruno Oliveira