review: fix: search in previous cases for variable declarations

src/main/java/spoon/reflect/visitor/filter/PotentialVariableDeclarationFunction.java

@@ -7,11 +7,15 @@
  */
 package spoon.reflect.visitor.filter;
 
+import spoon.reflect.code.CaseKind;
 import spoon.reflect.code.CtBodyHolder;
+import spoon.reflect.code.CtCase;
 import spoon.reflect.code.CtCatch;
 import spoon.reflect.code.CtCatchVariable;
 import spoon.reflect.code.CtLocalVariable;
+import spoon.reflect.code.CtStatement;
 import spoon.reflect.code.CtStatementList;
+import spoon.reflect.code.CtSwitch;
 import spoon.reflect.declaration.CtElement;
 import spoon.reflect.declaration.CtExecutable;
 import spoon.reflect.declaration.CtField;
@@ -27,6 +31,8 @@
 import spoon.reflect.visitor.chain.CtQuery;
 import spoon.reflect.visitor.chain.CtQueryAware;
 
+import java.util.List;
+
 /**
  * This mapping function searches for all {@link CtVariable} instances,
  * which might be a declaration of an input {@link CtElement}.
@@ -114,6 +120,23 @@ public void apply(CtElement input, CtConsumer<Object> outputConsumer) {
 				if (query.isTerminated()) {
 					return;
 				}
+			} else if (parent instanceof CtSwitch
+					&& scopeElement instanceof CtCase && ((CtCase<?>) scopeElement).getCaseKind() == CaseKind.COLON) {
+				SiblingsFunction siblingsFunction = new SiblingsFunction().mode(SiblingsFunction.Mode.PREVIOUS);
+				List<CtCase<?>> list = input.getFactory().createQuery()
+						.map(siblingsFunction)
+						.setInput(scopeElement)
+						.filterChildren(new TypeFilter<>(CtCase.class))
+						.list();
+
+				for (CtCase<?> c : list) {
+					for (CtStatement statement : c.getStatements()) {
+						if (statement instanceof CtLocalVariable && ((CtLocalVariable<?>) statement).getSimpleName().equals(variableName)) {
+							sendToOutput((CtVariable<?>) statement, outputConsumer);
+							return;
+						}
+					}
+				}
 			} else if (parent instanceof CtBodyHolder || parent instanceof CtStatementList) {
 				//visit all previous CtVariable siblings of scopeElement element in parent BodyHolder or Statement list
 				siblingsQuery.setInput(scopeElement).forEach(outputConsumer);

src/test/java/spoon/test/model/SwitchCaseTest.java

@@ -24,6 +24,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Nested;
@@ -41,13 +42,16 @@
 import spoon.reflect.code.CtStatement;
 import spoon.reflect.code.CtSwitch;
 import spoon.reflect.code.CtSwitchExpression;
+import spoon.reflect.code.CtVariableAccess;
 import spoon.reflect.code.CtYieldStatement;
 import spoon.reflect.declaration.CtClass;
 import spoon.reflect.declaration.CtElement;
 import spoon.reflect.declaration.CtMethod;
+import spoon.reflect.declaration.CtVariable;
 import spoon.reflect.factory.Factory;
 import spoon.reflect.visitor.filter.TypeFilter;
 import spoon.support.compiler.VirtualFile;
+import spoon.test.GitHubIssue;
 
 @DisplayName("Switchcase Tests")
 public class SwitchCaseTest {
@@ -229,6 +233,35 @@ public void testSwitchColons() {
 			);
 		}
 
+		@GitHubIssue(issueNumber = 4696, fixed = true)
+		void testVariableScopeInSwitch() {
+			// contract: different cases do not introduce different scopes in colon-switches
+			String code = "public class A {\n" +
+					"  public void function(int value) {\n" +
+					"    switch (value) {\n" +
+					"      case 1: { String test; }\n" + // decoy variable declaration, should not be found
+					"        String test;\n" +
+					"        test = \"first\";\n" +
+					"        break;\n" +
+					"      default:\n" +
+					"        test = \"not first\";\n" +
+					"    }\n" +
+					"  }\n" +
+					"}";
+			CtModel model = createModelFromString(code);
+			List<CtVariableAccess<?>> accesses = model.<CtVariableAccess<?>>getElements(new TypeFilter<>(CtVariableAccess.class))
+					.stream()
+					.filter(a -> a.getVariable().getSimpleName().equals("test"))
+					.collect(Collectors.<CtVariableAccess<?>>toList());
+			assertEquals(2, accesses.size());
+
+			// access their declarations
+			CtVariable<?> caseOneVariableDeclaration = accesses.get(0).getVariable().getDeclaration();
+			CtVariable<?> defaultVariableDeclaration = accesses.get(1).getVariable().getDeclaration();
+
+			// expect the declarations to be equal (writing to the same variable)
+			assertEquals(caseOneVariableDeclaration, defaultVariableDeclaration);
+		}
 	}
 
 	@Nested