Java: Add integration test for buildless lambda recovery

java/ql/integration-tests/java/lambda-expression-buildless-recovery/ExtractionErrors.expected

@@ -0,0 +1,3 @@
+| Frontend errors in file:  (2 errors during annotation processing) | 2 |
+| Frontend errors in file: Test.java (7 javac errors) | 2 |
+| Unknown errors in file: Test.java (5) | 2 |

java/ql/integration-tests/java/lambda-expression-buildless-recovery/ExtractionErrors.qlref

@@ -0,0 +1 @@
+Diagnostics/ExtractionErrors.ql

java/ql/integration-tests/java/lambda-expression-buildless-recovery/Test.java

@@ -0,0 +1,35 @@
+// The import below is intentionally commented out to test buildless recovery.
+// import java.util.stream.Stream;
+
+public class LambdaBuildlessRecoveryTest {
+
+    private Stream<String> getStringStream() {
+        return getStringStream();
+    }
+
+    public void testSimpleLambdaExpression() {
+        int unused = 0;
+        Stream<String> s = getStringStream();
+        Stream<String> mapped = s.map(x -> x);
+        mapped.forEach(System.out::println);
+    }
+
+    public void testLambdaWithBlockBody() {
+        int unused = 42;
+        Stream<String> s = getStringStream();
+        Stream<String> filtered = s.filter(item -> {
+            int unused = 42;
+            String proc = item.toUpperCase();
+            return proc.length() > 0;
+        });
+        filtered.forEach(System.out::println);
+    }
+
+    public void testVariableCapture() {
+        int unused = 99;
+        String prefix = "proc_";
+        Stream<String> s = getStringStream();
+        Stream<String> result = s.map(item -> prefix + item);
+        result.forEach(System.out::println);
+    }
+}

java/ql/integration-tests/java/lambda-expression-buildless-recovery/test.py

@@ -0,0 +1,5 @@
+def test(codeql, java, use_java_17):
+    codeql.database.create(
+        build_mode="none",
+        source_root="."
+    )

java/ql/integration-tests/java/lambda-expression-buildless-recovery/unused_variable.expected

@@ -0,0 +1,4 @@
+| Test.java:11:9:11:23 | int unused |
+| Test.java:18:9:18:24 | int unused |
+| Test.java:21:13:21:28 | int unused |
+| Test.java:29:9:29:24 | int unused |

java/ql/integration-tests/java/lambda-expression-buildless-recovery/unused_variable.ql

@@ -0,0 +1,5 @@
+import java
+
+from LocalVariableDecl v
+where not exists(v.getAnAccess()) and exists(v.getFile().getRelativePath())
+select v