Description

msullivan

opened on Sep 24, 2026

Issue body actions

Bug report

Bug description:

If we do a lazy import of two submodules in the same package tree (like pkg.a and pkg.b), then accessing pkg.a will cause pkg.b to get imported first. I think this is because pkg gets bound specifically to a lazy_import object for pkg.b. (In fact, just accessing pkg also imports pkg.b).

main.py:

lazy import pkg.a
lazy import pkg.b

print(globals()['pkg'])  # <lazy_import 'pkg.b'>

pkg.a  # triggers import of pkg (of course), pkg.b (sketchy!!), pkg.a (of course)

pkg/
├── __init__.py   # print("pkg")
├── a.py          # print("pkg.a")
└── b.py          # print("pkg.b")

This prints:

<lazy_import 'pkg.b'>
pkg
pkg.b
pkg.a

CPython versions tested on:

3.15

Operating systems tested on:

Linux

Linked PRs

• gh-158140: Do not eagerly import sibling submodules on lazy import #158491
• gh-158140: Resolve lazily imported sibling submodules independently #158521
• [3.15] gh-158140: Resolve lazily imported sibling submodules independently (GH-158521) #158613
• gh-158140: Resolve lazy submodules independently with custom import hooks #158815

Activity

1. msullivan

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Sep 24, 2026
2. aisk

   added

   topic-lazy-imports

   on Sep 25, 2026
3. StanFromIreland

   added

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   on Sep 25, 2026
4. pablogsal

   added

   release-blocker

   on Sep 30, 2026
5. github-project-automation

   added this to Release and Deferred blockers 🚫on Sep 30, 2026
6. github-project-automation

   moved this to Todo in Release and Deferred blockers 🚫on Sep 30, 2026
7. pablogsal

   added 2 commits that reference this issue on Oct 1, 2026

   pythongh-158140: Resolve lazily imported sibling submodules independe…

   56babbc

   pythongh-158140: Resolve lazy siblings through the pending-child regi…

   4e83bfa
8. Yhg1s

   added a commit that references this issue on Oct 2, 2026

   gh-158140: Resolve lazily imported sibling submodules independently (#…

   00a1c3a
9. Yhg1s

   closed this as completedin #158521on Oct 2, 2026
10. github-project-automation

    moved this from Todo to Done in Release and Deferred blockers 🚫on Oct 2, 2026
11. hugovk

    added a commit that references this issue on Oct 2, 2026

    [3.15] gh-158140: Resolve lazily imported sibling submodules independ…

    03bb26f
12. pablogsal

    added 4 commits that reference this issue on Oct 5, 2026

    pythongh-158140: Resolve lazy submodules independently with custom im…

    4f72c54

    pythongh-158140: Resolve lazy submodules independently with custom im…

    979f879

    pythongh-158140: Resolve lazy submodules independently with custom im…

    63a9bca

    pythongh-158140: Resolve lazy submodules independently with custom im…

    200bac8
13. Kronuz

    added a commit that references this issue on Oct 5, 2026

    [3.15] pythongh-158140: Resolve lazily imported sibling submodules in…

    bcb3aa6
14. ambv

    added a commit that references this issue on Oct 20, 2026

    pythongh-158140: Resolve lazy submodules independently with custom im…

    94b13f3

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