Bug 459320: [ImportRewrite] adds import for declared package when pasting to CU outside of classpath

2 files changed, 49 insertions, 3 deletions

diff --git a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ImportRewriteTest.java b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ImportRewriteTest.java
index e1d22922d3..f5c7ca01d7 100644
--- a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ImportRewriteTest.java
+++ b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/rewrite/describing/ImportRewriteTest.java
@@ -18,8 +18,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
-import junit.framework.Test;
-
+import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.ProjectScope;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.Platform;
@@ -49,6 +48,8 @@ import org.eclipse.text.edits.MultiTextEdit;
 import org.eclipse.text.edits.TextEdit;
 import org.osgi.service.prefs.BackingStoreException;
 
+import junit.framework.Test;
+
 @SuppressWarnings({"rawtypes", "unchecked"})
 public class ImportRewriteTest extends AbstractJavaModelTests {
 
@@ -1441,6 +1442,30 @@ public class ImportRewriteTest extends AbstractJavaModelTests {
 		expected.append("public class Clazz {}\n");
 		assertEqualString(cu.getSource(), expected.toString());
 	}
+	
+	// https://bugs.eclipse.org/459320
+	public void testAddImportToCuNotOnClasspath() throws Exception {
+		StringBuffer contents = new StringBuffer();
+		contents.append("package pack1;\n");
+		contents.append("\n");
+		contents.append("public class Clazz {}\n");
+		
+		createFolder("/P/alt-src/pack1/");
+		IFile clazz = createFile("/P/alt-src/pack1/Clazz.java", contents.toString());
+		ICompilationUnit cu = (ICompilationUnit) JavaCore.create(clazz);
+		cu.becomeWorkingCopy(null);
+		
+		try {
+			ImportRewrite rewrite = newImportsRewrite(cu, new String[] {}, 999, 999, true);
+			rewrite.setUseContextToFilterImplicitImports(true);
+			rewrite.addImport("pack1.AnotherClass");
+			apply(rewrite);
+			
+			assertEqualString(cu.getSource(), contents.toString());
+		} finally {
+			cu.discardWorkingCopy();
+		}
+	}
 
 	public void testAddImports1() throws Exception {
 
diff --git a/org.eclipse.jdt.core/dom/org/eclipse/jdt/internal/core/dom/rewrite/imports/ImportRewriteConfiguration.java b/org.eclipse.jdt.core/dom/org/eclipse/jdt/internal/core/dom/rewrite/imports/ImportRewriteConfiguration.java
index c77fee8582..2055df1c3a 100644
--- a/org.eclipse.jdt.core/dom/org/eclipse/jdt/internal/core/dom/rewrite/imports/ImportRewriteConfiguration.java
+++ b/org.eclipse.jdt.core/dom/org/eclipse/jdt/internal/core/dom/rewrite/imports/ImportRewriteConfiguration.java
@@ -18,6 +18,9 @@ import java.util.List;
 import java.util.Set;
 
 import org.eclipse.jdt.core.ICompilationUnit;
+import org.eclipse.jdt.core.IJavaElement;
+import org.eclipse.jdt.core.IPackageDeclaration;
+import org.eclipse.jdt.core.JavaModelException;
 import org.eclipse.jdt.internal.core.JavaProject;
 
 /**
@@ -159,7 +162,25 @@ public final class ImportRewriteConfiguration {
 
 				implicitImportContainerNames.add("java.lang"); //$NON-NLS-1$
 
-				String compilationUnitPackageName = compilationUnit.getParent().getElementName();
+				IJavaElement packageFragment = compilationUnit.getParent();
+				String compilationUnitPackageName = packageFragment.getElementName();
+				if (compilationUnitPackageName.isEmpty() && !packageFragment.exists() && compilationUnit.exists()) {
+					/*
+					 * For a file outside of the build path, JavaCore#create(IFile) creates an
+					 * ICompilationUnit with the file's parent folder as package fragment root, and a default package.
+					 * That "wrong" package is problematic for the ImportRewrite, since it doesn't get filtered
+					 * and eventually leads to unused import statements.
+					 */
+					try {
+						IPackageDeclaration[] packageDeclarations = compilationUnit.getPackageDeclarations();
+						if (packageDeclarations.length > 0) {
+							implicitImportContainerNames.add(packageDeclarations[0].getElementName());
+							return implicitImportContainerNames;
+						}
+					} catch (JavaModelException e) {
+						// continue
+					}
+				}
 				implicitImportContainerNames.add(compilationUnitPackageName);
 
 				return implicitImportContainerNames;