ASTParser sometimes failing at resolving package with modules

[mickaelistria]

Add this to ModuleBuilderTests

	public void testAutoModule3_ASTParser() throws Exception {
		IJavaProject javaProject = null, auto = null;
		try {
			auto = createJava9Project("auto", new String[] {"src"});
			createFolder("auto/src/p/a");
			createFile("auto/src/p/a/X.java",
				"package p.a;\n" +
				"public class X {}\n;");
			createFolder("auto/META-INF");
			createFile("auto/META-INF/MANIFEST.MF",
				"Manifest-Version: 1.0\n" +
				"Automatic-Module-Name: org.eclipse.lib.x\n");

			javaProject = createJava9Project("mod.one", new String[] {"src"});
			IClasspathAttribute[] attributes = { JavaCore.newClasspathAttribute(IClasspathAttribute.MODULE, "true") };
			addClasspathEntry(javaProject, JavaCore.newProjectEntry(auto.getPath(), null, false, attributes, false));

			String srcMod =
				"module mod.one { \n" +
				"	requires org.eclipse.lib.x;\n" + // from manifest attribute
				"}";
			createFile("/mod.one/src/module-info.java",
				srcMod);
			createFolder("mod.one/src/q");
			String srcX =
				"package q;\n" +
				"public class X {\n" +
				"	p.a.X f;\n" +
				"}";
			createFile("/mod.one/src/q/X.java", srcX);
			auto.getProject().build(IncrementalProjectBuilder.FULL_BUILD, null);

			ASTParser parser = ASTParser.newParser(AST.getJLSLatest());
			parser.setResolveBindings(true);
			parser.setProject(javaProject);
			parser.setSource(getWorkingCopy("/mod.one/src/q/X.java", srcX, true));
			CompilationUnit unit = (CompilationUnit) parser.createAST(null);
			assertArrayEquals(new IProblem[0], unit.getProblems());
		} finally {
			if (javaProject != null)
				deleteProject(javaProject);
			if (auto != null)
				deleteProject(auto);
		}
	}

and see it wrongly fail with

array lengths differed, expected.length=0 actual.length=1; arrays first differed at element [0]; expected:<end of array> but was:<Pb(1450) The type p.a.X is not accessible>
	at org.junit.internal.ComparisonCriteria.arrayEquals(ComparisonCriteria.java:89)
	at org.junit.internal.ComparisonCriteria.arrayEquals(ComparisonCriteria.java:28)
	at org.junit.Assert.internalArrayEquals(Assert.java:534)
	at org.junit.Assert.assertArrayEquals(Assert.java:285)
	at org.junit.Assert.assertArrayEquals(Assert.java:300)
	at org.eclipse.jdt.core.tests.model.ModuleBuilderTests.testAutoModule3_ASTParser(ModuleBuilderTests.java:5331)

When working on this with #2300, the proposed quickfix was causing a StackOverflowError that can be reproduced when applying the patch and running this from ResolveTests9

	public void testModuleInfo_ASTParser() throws CoreException {
		IFile providesFile = createFile("/Resolve/src/provides.java", "public class provides {}");
		IFile modInfo = null;
		try {
			getWorkingCopy(
					"/Resolve/src/test/ITest.java",
					"public interface ITest {}\n");
			getWorkingCopy(
					"/Resolve/src/test/TestClass.java",
					"public class TestClass implements ITest {}\n");

			this.wc = getWorkingCopy(
					"/Resolve/src/module-info.java",
					"module com.test {\n" +
					"  provides p1.Y with ResolveInterface;\n" +
					"}\n");

			ASTParser parser = ASTParser.newParser(AST.getJLSLatest());
			parser.setResolveBindings(true);
			parser.setProject(this.currentProject);
			parser.setSource(this.wc);
			CompilationUnit unit = (CompilationUnit) parser.createAST(null);
			assertArrayEquals(new IProblem[0], unit.getProblems());
		} finally {
			deleteResource(providesFile);
			if (modInfo != null)
				deleteResource(modInfo);
		}
	}

[mickaelistria]

Here is another example, which can be run from ReconcilerTests9

public void testBug544306_ASTParser() throws Exception {
	if (!isJRE9)
		return;
	IJavaProject p1 = createJava9Project("p1");
	IJavaProject p2 = createJava9Project("p2");
	try {
		createFolder("p1/src/p1");
		createFile("p1/src/p1/P1.java",
				"package p1;\n" +
				"public class P1 {\n" +
				"}\n");
		createFile("p1/src/module-info.java",
				"module p1 {\n" +
				"	exports p1;\n" +
				"}\n");

		IClasspathAttribute[] testAttrs = { JavaCore.newClasspathAttribute("test", "true") };
		addClasspathEntry(p2, JavaCore.newProjectEntry(p1.getPath(), null, false, testAttrs, false));
		addClasspathEntry(p2, JavaCore.newSourceEntry(new Path("/p2/src-test"), null, null, new Path("/p2/bin-test"), testAttrs));
		createFolder("p2/src/p2");
		createFolder("p2/src-test/p2");

		createFile("p2/src/module-info.java",
				"module p2 {\n" +
				"}\n");
		String testSource = "package p2;\n" +
		"import p1.P1;\n" +
		"class Test extends P1{ }";

		createFile("p2/src-test/p2/Test.java", testSource);
		waitForAutoBuild();
		IMarker[] markers = p1.getProject().findMarkers(null, true, IResource.DEPTH_INFINITE);
		assertMarkers("Unexpected markers",
				"",  markers);

		this.workingCopy.discardWorkingCopy();
		this.workingCopy = getCompilationUnit("p2/src-test/p2/Test.java").getWorkingCopy(this.wcOwner, null);
		ASTParser parser = ASTParser.newParser(AST.getJLSLatest());
		parser.setResolveBindings(true);
		parser.setSource(this.workingCopy);
		parser.setWorkingCopyOwner(this.wcOwner);
		CompilationUnit unit = (CompilationUnit)parser.createAST(null);
		assertArrayEquals(new IProblem[0], unit.getProblems());
		this.workingCopy.discardWorkingCopy();
	} finally {
		deleteProject(p1);
		deleteProject(p2);
	}
}

[stephan-herrmann]

Coming from #3273 (comment) I wanted to check the status of this (due to connection to StackOverflowError):

When working on this with #2300, the proposed quickfix was causing a StackOverflowError that can be reproduced when applying the patch and running this from ResolveTests9

	public void testModuleInfo_ASTParser() throws CoreException {
		IFile providesFile = createFile("/Resolve/src/provides.java", "public class provides {}");
		IFile modInfo = null;
		try {
			getWorkingCopy(
					"/Resolve/src/test/ITest.java",
					"public interface ITest {}\n");
			getWorkingCopy(
					"/Resolve/src/test/TestClass.java",
					"public class TestClass implements ITest {}\n");

			this.wc = getWorkingCopy(
					"/Resolve/src/module-info.java",
					"module com.test {\n" +
					"  provides p1.Y with ResolveInterface;\n" +
					"}\n");

			ASTParser parser = ASTParser.newParser(AST.getJLSLatest());
			parser.setResolveBindings(true);
			parser.setProject(this.currentProject);
			parser.setSource(this.wc);
			CompilationUnit unit = (CompilationUnit) parser.createAST(null);
			assertArrayEquals(new IProblem[0], unit.getProblems());
		} finally {
			deleteResource(providesFile);
			if (modInfo != null)
				deleteResource(modInfo);
		}
	}

Observations: On HEAD of master (before #3384) this test throws ISE("Missing system library"), likely due to unconfigured this.currentProject. Moving the test to ResolveTest23 it passes without further ado.

@mickaelistria do you have any further hints? The original stack trace? Note that ResolveTests9 has no relevant changes since this ticket was filed in April.

[mickaelistria]

Sorry, I have lost memory about this case and won't spend further time on it on short term. So if you think it's better, feel free to close it. If needed, I'll reopen or recreate it later.