swiftlang / swiftlang/swift-java
Translating Foundation types requires explicit Foundation import
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Description
The Foundation types are currently translated in full only when there is an explicit Foundation import in the source files where they are used. IIUC, this way Swift Java guards against user-defined Data types since it can't typecheck the Data use site. This behavior is visible in Samples/SwiftJavaExtractFFMSampleApp/Sources/MySwiftLibrary/MySwiftLibrary.swift if you switch import Foundation to import AppKit, which I think exports the Foundation through the modulemap, and run the sample. The jextract task succeeds, but the Java compilation fails because the Data.java wrapper is missing the expected APIs.
Similarly, the @_exported import Foundation doesn't seem to work.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with Samples/SwiftJavaExtractFFMSampleApp/Sources/MySwiftLibrary/MySwiftLibrary.swift and reproduce the issue by replacing import Foundation with import AppKit, then run the jextract task. Compare the generated wrappers and Java compilation results, including the @_exported import Foundation case. Done means Foundation types such as Data receive the expected APIs and the sample compiles successfully without an explicit Foundation import.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java, swift
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 48/100