swift-java jextract: `--mode` argument ignored

[gmondada]

The --mode jni argument is ignored on swift-java jextract. Code is generated in ffm mode.

To reproduce the problem, just run the command:

cd /tmp
swift-java jextract --mode jni --swift-module Foo --input-swift foo_in --output-swift foo_out/swift --output-java foo_out/java

The output is:

[info][swift-java] Run JExtractCommand: swift-java jextract --mode jni --swift-module Foo --input-swift foo_in --output-swift foo_out/swift --output-java foo_out/java
[info][swift-java] Current work directory: /private/tmp
[debug][swift-java] Load config from module base directory: /private/tmp/Sources/Foo
[debug][swift-java] Running 'swift-java jextract' in mode: ffm
[debug][swift-java] Dependent configs: 0
[warning][JExtractSwiftLib/Swift2Java.swift:39](run()) Configured java package is '', consider specifying concrete package for generated sources. 
[info][JExtractSwiftLib/Swift2Java.swift:46](run()) Input swift = foo_in 
[info][JExtractSwiftLib/Swift2Java.swift:48](run()) Input paths = [foo_in] 
[info][JExtractSwiftLib/Swift2Java.swift:55](run()) Input path: foo_in 
[swift-java] Generated: FooModule+SwiftJava.swift (at foo_out/swift/FooModule+SwiftJava.swift -- file:///private/tmp/)
[swift-java] Generated Swift sources (module: 'Foo') in: foo_out/swift/
[swift-java] Generated: Foo.java (at foo_out/java/Foo.java -- file:///private/tmp/)
[swift-java] Generated Java sources (package: '') in: foo_out/java/
[swift-java] Imported Swift module 'Foo': done.
[debug][swift-java] Done: swift-java jextract --mode jni --swift-module Foo --input-swift foo_in --output-swift foo_out/swift --output-java foo_out/java

On the 4th line, you see that the selected mode is ffm.

I can work around the problem by creating a swift-java.config file in the Sources/Foo folder.

Environment:

• MacOS 15.6.1
• swift-6.2-RELEASE (OSS)
• swift-java: 9236194