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Keep the placeholder structure private to lazyimportobject.c. Move the resolution and attribute lookup code there so it can use the structure without exposing its fields to the eval loop or import code.
Let importlib handle module locks instead of holding the global import lock while resolving a placeholder. Keep active placeholders in a set on the thread and remove them on every exit, including allocation failures. Use the same cycle and recursion checks when a hook returns a placeholder. Keep the source references alive until all attribute lookups finish.
Keep an existing cause or context when resolution fails. Add the import location as a note in that case, without adding the same note twice. Errors without an existing chain still get the declaration as their cause.
Only reuse a concrete attribute from a module that has finished loading. Leave lazy attributes for resolution so module hooks still get a chance. Check the module again after reading its spec, and keep interrupts visible.
Normalize the fromlist before calling the filter and check its items before registering imports. Use one cleanup path and the existing filter accessor. Pass the same five arguments to custom lazy hooks as to __import__.
Resolve lazy __getattr__ and __dir__ hooks before calling them. Treat a hook already being resolved as unavailable so it can import a sibling. Bind a loaded child before removing its pending entry. Recheck the module dict when another thread may have completed the load. Reuse modules already in sys.modules during package cycles, and simplify child registration.
Remember the namespace where lookup found the placeholder and use one helper to resolve and replace it. Only replace a binding that still holds the same placeholder, preserving assignments and deletions during import. Check and replace ordinary dict entries atomically. Keep the mapping protocol for custom namespaces and allow reads from readonly namespaces. Reuse the global lookup helper in the eval loop and remove the duplicate.
Loading a child can replace the parent binding with the module before we fetch the imported attribute. Keep the module returned by the normal importer so the shared helper can replace it in its actual parent namespace. Other values and deletions still prevent replacement, and custom hooks keep control of their assignments.
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Fixes #158140. With
lazy import pkg.afollowed bylazy import pkg.b, accessingpkg.acurrently importspkg.bfirst. Resolve the package and each pending child independently, while preserving assigned package attributes, import hooks, invalid-import errors and retries after failed imports.This is stacked on #158282 at
ad34faea95935c9cedfb940930e3c377322a4e09. Its commits are included until that PR lands. The fix-only diff shows the changes for this issue.lazy import pkg.a) also imports a later importedpkg.b#158140