Fix folding of 2 consecutive methods

If the second method starts in the same line the first one ends then
there will still be 2 foldings.

Fixes eclipse-jdt#1539

org.eclipse.jdt.ui.tests/ui/org/eclipse/jdt/ui/tests/folding/FoldingTest.java

@@ -0,0 +1,101 @@
+package org.eclipse.jdt.ui.tests.folding;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+import org.eclipse.core.runtime.CoreException;
+
+import org.eclipse.jface.text.IRegion;
+import org.eclipse.jface.text.Position;
+import org.eclipse.jface.text.Region;
+import org.eclipse.jface.text.source.Annotation;
+import org.eclipse.jface.text.source.projection.ProjectionAnnotation;
+import org.eclipse.jface.text.source.projection.ProjectionAnnotationModel;
+
+import org.eclipse.ui.PartInitException;
+
+import org.eclipse.jdt.core.ICompilationUnit;
+import org.eclipse.jdt.core.IJavaProject;
+import org.eclipse.jdt.core.IPackageFragment;
+import org.eclipse.jdt.core.IPackageFragmentRoot;
+import org.eclipse.jdt.core.JavaModelException;
+
+import org.eclipse.jdt.ui.tests.core.rules.ProjectTestSetup;
+
+import org.eclipse.jdt.internal.ui.javaeditor.EditorUtility;
+import org.eclipse.jdt.internal.ui.javaeditor.JavaEditor;
+
+
+
+public class FoldingTest {
+	 @Rule
+    public ProjectTestSetup projectSetup = new ProjectTestSetup();
+
+    private IJavaProject jProject;
+    private IPackageFragmentRoot sourceFolder;
+    private IPackageFragment packageFragment;
+
+	@Before
+    public void setUp() throws CoreException {
+        jProject = projectSetup.getProject();
+        sourceFolder = jProject.findPackageFragmentRoot(jProject.getResource().getFullPath().append("src"));
+        if (sourceFolder == null) {
+            sourceFolder = org.eclipse.jdt.testplugin.JavaProjectHelper.addSourceContainer(jProject, "src");
+        }
+        packageFragment = sourceFolder.createPackageFragment("org.example.test", false, null);
+    }
+
+    @After
+    public void tearDown() throws CoreException {
+        org.eclipse.jdt.testplugin.JavaProjectHelper.delete(jProject);
+    }
+
+    @Test
+    public void testMethodDeclarationFoldingWithSameLineStart() throws JavaModelException, PartInitException {
+        String str = """
+            package org.example.test;
+            public class Q {
+                void a() {
+        		    int i = 0;
+                }void b() {
+                }
+            }
+            """;
+        List<IRegion> regions = getProjectionRangesOfFile(str);
+        assertTrue(regions.size() >= 2);
+
+        regions.sort((r1, r2) -> Integer.compare(r1.getOffset(), r2.getOffset()));
+        IRegion methodARegion = regions.get(0);
+        IRegion methodBRegion = regions.get(1);
+        int methodAEnd = methodARegion.getOffset() + methodARegion.getLength();
+        int methodBStart = methodBRegion.getOffset();
+
+        assertTrue(methodBStart >= methodAEnd);
+    }
+
+
+	private List<IRegion> getProjectionRangesOfFile(String str) throws JavaModelException, PartInitException {
+        ICompilationUnit cu = packageFragment.createCompilationUnit("TestFolding.java", str, true, null);
+        JavaEditor editor = (JavaEditor) EditorUtility.openInEditor(cu);
+        ProjectionAnnotationModel model = editor.getAdapter(ProjectionAnnotationModel.class);
+        List<IRegion> regions = new ArrayList<>();
+        Iterator<Annotation> it = model.getAnnotationIterator();
+        while (it.hasNext()) {
+            Annotation a = it.next();
+            if (a instanceof ProjectionAnnotation) {
+                Position p = model.getPosition(a);
+                regions.add(new Region(p.getOffset(), p.getLength()));
+            }
+        }
+        return regions;
+    }
+
+}

org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/text/folding/DefaultJavaFoldingStructureProvider.java

@@ -1279,23 +1279,15 @@ protected final IRegion alignRegion(IRegion region, FoldingStructureComputationC
 		IDocument document= ctx.getDocument();
 
 		try {
-
 			int start= document.getLineOfOffset(region.getOffset());
-			int end= document.getLineOfOffset(region.getOffset() + region.getLength());
+			int end= document.getLineOfOffset(region.getOffset() + region.getLength() - 1);
 			if (start >= end)
 				return null;
-
-			int offset= document.getLineOffset(start);
-			int endOffset;
-			if (document.getNumberOfLines() > end + 1)
-				endOffset= document.getLineOffset(end + 1);
-			else
-				endOffset= document.getLineOffset(end) + document.getLineLength(end);
+			int offset = document.getLineOffset(start);
+			int endOffset = document.getLineOffset(end);
 
 			return new Region(offset, endOffset - offset);
-
 		} catch (BadLocationException x) {
-			// concurrent modification
 			return null;
 		}
 	}