Plugin generated generate-documentation command must include necessary -I for target to build correctly (SwiftJava can't docc)

[ktoso]

The docc plugin should be able to generate docs for libraries, like SwiftJava which need to pass -I in order to include the necessary libraries that they're wrapping.

For example, for such target:

    .target(
      name: "JavaKit",
      dependencies: [
        "JavaRuntime",
        "JavaKitMacros",
        "JavaTypes",
        "JavaKitConfigurationShared", // for Configuration reading at runtime
      ],
      exclude: ["swift-java.config"],
      swiftSettings: [
        .swiftLanguageMode(.v5),
        .unsafeFlags([
          "-I\(javaIncludePath)", 
          "-I\(javaPlatformIncludePath)"
        ], 
        .when(platforms: [.macOS, .linux, .windows]))
      ],
      linkerSettings: [
        .unsafeFlags(
          [
            "-L\(javaHome)/lib/server",
            "-Xlinker", "-rpath",
            "-Xlinker", "\(javaHome)/lib/server",
          ],
          .when(platforms: [.linux, .macOS])
        ),
        .unsafeFlags(
          [
            "-L\(javaHome)/lib"
          ],
          .when(platforms: [.windows])),
        .linkedLibrary(
          "jvm",
          .when(platforms: [.linux, .macOS, .windows])
        ),
      ]
    ),

Expected behavior

The generated command should carry along all -I options from the target that was built.

Expected command for SwiftJava for example:

 /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/bin/swift-symbolgraph-extract -module-name JavaKit -target arm64-apple-macosx15.0 -module-cache-path /Users/ktoso/code/swift-java/.build/arm64-apple-macosx/debug/ModuleCache -I /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/lib/swift/macosx/testing -L /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/lib/swift/macosx/testing -plugin-path /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/lib/swift/host/plugins/testing -sdk /Library/Developer/CommandLineTools/SDKs/MacOSX14.5.sdk -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks -I /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib -L /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib -Xcc -fmodule-map-file=/Users/ktoso/code/swift-java/Sources/JavaRuntime/include/module.modulemap -Xcc -I -Xcc /Users/ktoso/code/swift-java/Sources/JavaRuntime/include -I /Users/ktoso/code/swift-java/.build/arm64-apple-macosx/debug/Modules -minimum-access-level public -skip-inherited-docs -emit-extension-block-symbols -output-dir /Users/ktoso/code/swift-java/.build/arm64-apple-macosx/extracted-symbols/swift-java/JavaKit \
-I (THE "-I\(javaIncludePath)" FROM PACKAGE.SWIFT FOR THIS TARGET) \
-I (THE "-I\(javaPlatformIncludePath)" FROM PACKAGE.SWIFT FOR THIS TARGET) \

note the last two lines

Actual behavior

The plugin generates

 /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/bin/swift-symbolgraph-extract -module-name JavaKit -target arm64-apple-macosx15.0 -module-cache-path /Users/ktoso/code/swift-java/.build/arm64-apple-macosx/debug/ModuleCache -I /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/lib/swift/macosx/testing -L /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/lib/swift/macosx/testing -plugin-path /Users/ktoso/Library/Developer/Toolchains/swift-6.1.2-RELEASE.xctoolchain/usr/lib/swift/host/plugins/testing -sdk /Library/Developer/CommandLineTools/SDKs/MacOSX14.5.sdk -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks -F /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks -I /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib -L /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/usr/lib -Xcc -fmodule-map-file=/Users/ktoso/code/swift-java/Sources/JavaRuntime/include/module.modulemap -Xcc -I -Xcc /Users/ktoso/code/swift-java/Sources/JavaRuntime/include -I /Users/ktoso/code/swift-java/.build/arm64-apple-macosx/debug/Modules -minimum-access-level public -skip-inherited-docs -emit-extension-block-symbols -output-dir /Users/ktoso/code/swift-java/.build/arm64-apple-macosx/extracted-symbols/swift-java/JavaKit 

which is missing necessary include paths, and therefore fails to build:

<module-includes>:1:9: note: in file included from <module-includes>:1:
#import "JavaRuntime.h"
        ^
/Users/ktoso/code/swift-java/Sources/JavaRuntime/include/JavaRuntime.h:18:10: error: 'jni.h' file not found
#include <jni.h> 🔥🔥🔥
         ^
<unknown>:0: error: could not build Objective-C module 'JavaRuntime'
Error: Failed to load the module 'JavaKit'. Are you missing build dependencies or include/framework directories?
See the previous error messages for details. Aborting.

Steps to Reproduce

git clone https://github.com/swiftlang/swift-java
cd swift-java
swift package --allow-writing-to-directory .docs generate-documentation --output-path .docs --target JavaKit

In case the JavaKit target was renamed it may already be named SwiftJNI, ping me if confused.

Swift-DocC Plugin Version Information

Swift-DocC plugin version: latest head at 7935a77
Swift Compiler version:

-> % swift -version
Apple Swift version 6.1.2 (swift-6.1.2-RELEASE)
Target: arm64-apple-macosx14.0