[Mirror] Handle fields of thin metatypes. #76309
Merged
+66
−0
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Fields containing metatypes with no possible subtypes are thin i.e. they have no storage. There is only one possible value they can have: the corresponding type. Mirror attempted to copy the nonexistent field value from the nonexistent storage, producing garbage. Instead, special-case thin metatypes and copy the instance type out of the metatype metadata rather than trying to copy it from the field. rdar://108280543
mikeash
force-pushed
the
mirror-thin-metatypes
branch
from
65a512b
to
7d34513
Compare
|
@swift-ci please test |
stmontgomery
approved these changes
Sep 9, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fields containing metatypes with no possible subtypes are thin i.e. they have no storage. There is only one possible value they can have: the corresponding type. Mirror attempted to copy the nonexistent field value from the nonexistent storage, producing garbage. Instead, special-case thin metatypes and copy the instance type out of the metatype metadata rather than trying to copy it from the field.
rdar://108280543