[native-image] Classpath not honored when adding resources

[ozppupbg]

Hello,

I have an application, which reads its version information from the META-INF/MANIFEST.MF file. I added this file to the image resources, but the file I get at runtime is not from my jar.

I checked the resource inclusion with the option "-H:Log=registerResource:" and see 5 or 6 MANIFEST.MF files added.
Of course the last one wins and is the one present in the native image. As my only input is a single jar file I would have expected my version be in the image. But interesting enough it is neither the first MANIFEST.MF file in the classpath, but one in the middle.
As all jar files except mine, are from "graalvm/lib/svm/builder/" I don't see an easy way to fix this from my side.

I'm using the latest GraalVM Community Edition 19.3.0 amd64 for Linux.

Thank you!

Regards,

Oz

[jaikiran]

Hello @ozppupbg,

I have an application, which reads its version information from the META-INF/MANIFEST.MF file.

Which API do you use to get hold of that file? Can you paste that snippet? Is it the ClassLoader.getResource or ClassLoader.getResourceAsStream? Can you try ClassLoader.getResources instead?

[ozppupbg]

Hello @jaikiran,

I tried clazz.getResource, but for now have settled with manifestPath = "resource:META-INF/MANIFEST.MF"; manifest = new Manifest(new URL(manifestPath).openStream());, which should work, as it is native-image specific.

By now I also verified, that all included MANIFEST.MF files seem to present in the binary as strings.

These should be the code parts resposible for getting the resource file if I use this method:

graal/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/JavaNetSubstitutions.java

Lines 187 to 197 in d30871f

	public InputStream getInputStream() throws IOException {
	Resources.ResourcesSupport support = ImageSingletons.lookup(Resources.ResourcesSupport.class);
	// remove "protcol:" from url to get the resource name
	String resName = url.toString().substring(1 + JavaNetSubstitutions.RESOURCE_PROTOCOL.length());
	final List<byte[]> bytes = support.resources.get(resName);
	if (bytes == null || bytes.size() < 1) {
	return null;
	} else {
	return new ByteArrayInputStream(bytes.get(0));
	}
	}

graal/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/Resources.java

Lines 72 to 108 in 36e9f9b

	@Platforms(Platform.HOSTED_ONLY.class)
	public static void registerResource(String name, InputStream is) {
	ResourcesSupport support = ImageSingletons.lookup(ResourcesSupport.class);
	byte[] arr = new byte[4096];
	int pos = 0;
	try {
	for (;;) {
	if (pos == arr.length) {
	byte[] tmp = new byte[arr.length * 2];
	System.arraycopy(arr, 0, tmp, 0, arr.length);
	arr = tmp;
	}
	int len = is.read(arr, pos, arr.length - pos);
	if (len == -1) {
	break;
	}
	pos += len;
	}
	} catch (IOException ex) {
	throw VMError.shouldNotReachHere(ex);
	}
	byte[] res = new byte[pos];
	System.arraycopy(arr, 0, res, 0, pos);
	List<byte[]> list = support.resources.get(name);
	if (list == null) {
	list = new ArrayList<>();
	support.resources.put(name, list);
	}
	list.add(res);
	}
	public static List<byte[]> get(String name) {
	return ImageSingletons.lookup(ResourcesSupport.class).resources.get(name);
	}

If multiple resources with the same name are registered, the first one should be "winning".

Regards,

Oz

[peter-hofer]

Thank you for your report @ozppupbg and apologies for the late reply. The resources should indeed be in the order in which they are found on the class path for ClassLoader.getResources and getSystemResources, and getResource and getSystemResource should pick the first one. However, this is still different to how multiple ClassLoaders (can) provide resources and might not be a universal solution.

[jovanstevanovic]

PR #3315 will fix this issue.

[jovanstevanovic]

The PR that fixes this problem is on a master for a while, so I'm going to close this issue.