Add support for enum value comparison (#7418)

enum value is expressed as string with either fully qualified name,
simple name with enum class of just the enum value.

Author: jpbempel

dd-java-agent/agent-debugger/debugger-el/src/main/java/com/datadog/debugger/el/expressions/ComparisonOperator.java

@@ -21,11 +21,52 @@ public Boolean apply(Value<?> left, Value<?> right) {
         }
         return compare(leftNumber, rightNumber) == 0;
       }
+      if (left.getValue() instanceof Enum || right.getValue() instanceof Enum) {
+        return applyEqualityForEnum(left, right);
+      }
       if (left.getValue().getClass() == right.getValue().getClass()) {
         return Objects.equals(left.getValue(), right.getValue());
       }
       return Boolean.FALSE;
     }
+
+    private Boolean applyEqualityForEnum(Value<?> left, Value<?> right) {
+      if (left.getValue() instanceof Enum && right instanceof StringValue) {
+        return doApplyEqualityForEnum(left, right);
+      }
+      if (left instanceof StringValue && right.getValue() instanceof Enum) {
+        return doApplyEqualityForEnum(right, left);
+      }
+      throw new EvaluationException(
+          "Equality operator is not supported for the given types: "
+              + left.getValue().getClass().getName()
+              + " and "
+              + right.getValue().getClass().getName(),
+          null);
+    }
+
+    private Boolean doApplyEqualityForEnum(Value<?> enumExpr, Value<?> enumValueExpr) {
+      Enum<?> enumValue = (Enum<?>) enumExpr.getValue();
+      String enumValueStr = (String) enumValueExpr.getValue();
+      Class<? extends Enum> enumClass = enumValue.getClass();
+      Enum[] enumConstants = enumClass.getEnumConstants();
+      for (Enum<?> enumConstant : enumConstants) {
+        // Check if string constant as value expression matches for enum constant
+        // the endsWith allow to match either:
+        // - the full enum constant name (com.datadog.debugger.MyEnum.ONE)
+        // - the simple name with enum class name (MyEnum.ONE)
+        // - the simple name (ONE)
+        // The second check against enumValue is to ensure the instance filtered based on the
+        // name is still correct because the name can partially match (CLOSE in OPENCLOSE)
+        // with an enum defined like (OPEN, CLOSE, OPENCLOSE)
+        if (enumValueStr.endsWith(enumConstant.name())) {
+          if (enumValue.equals(enumConstant)) {
+            return Boolean.TRUE;
+          }
+        }
+      }
+      return Boolean.FALSE;
+    }
   },
   GE(">=") {
     @Override

dd-java-agent/agent-debugger/debugger-el/src/test/java/com/datadog/debugger/el/expressions/ComparisonExpressionTest.java

@@ -16,6 +16,7 @@
 import com.datadog.debugger.el.values.StringValue;
 import datadog.trace.bootstrap.debugger.el.ValueReferenceResolver;
 import java.math.BigDecimal;
+import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
 import java.util.Random;
 import java.util.stream.Stream;
@@ -164,7 +165,37 @@ private static Stream<Arguments> expressions() {
             new StringValue("java.lang.Double"),
             INSTANCEOF,
             true,
-            "1.0 instanceof \"java.lang.Double\""));
+            "1.0 instanceof \"java.lang.Double\""),
+        Arguments.of(
+            new ObjectValue(StandardOpenOption.READ),
+            new StringValue("READ"),
+            EQ,
+            true,
+            "java.nio.file.StandardOpenOption == \"READ\""),
+        Arguments.of(
+            new ObjectValue(StandardOpenOption.READ),
+            new StringValue("StandardOpenOption.READ"),
+            EQ,
+            true,
+            "java.nio.file.StandardOpenOption == \"StandardOpenOption.READ\""),
+        Arguments.of(
+            new ObjectValue(StandardOpenOption.READ),
+            new StringValue("java.nio.file.StandardOpenOption.READ"),
+            EQ,
+            true,
+            "java.nio.file.StandardOpenOption == \"java.nio.file.StandardOpenOption.READ\""),
+        Arguments.of(
+            new ObjectValue(StandardOpenOption.CREATE),
+            new StringValue("READ"),
+            EQ,
+            false,
+            "java.nio.file.StandardOpenOption == \"READ\""),
+        Arguments.of(
+            new StringValue("READ"),
+            new ObjectValue(StandardOpenOption.READ),
+            EQ,
+            true,
+            "\"READ\" == java.nio.file.StandardOpenOption"));
   }
 
   @ParameterizedTest

dd-java-agent/agent-debugger/src/test/java/com/datadog/debugger/agent/CapturedSnapshotTest.java

@@ -1776,6 +1776,34 @@ public void enumValues() throws IOException, URISyntaxException {
         "TWO");
   }
 
+  @Test
+  public void enumCondition() throws IOException, URISyntaxException {
+    final String CLASS_NAME = "com.datadog.debugger.CapturedSnapshot23";
+    LogProbe probe =
+        createProbeBuilder(PROBE_ID, CLASS_NAME, "convert", null)
+            .evaluateAt(MethodLocation.EXIT)
+            .when(
+                new ProbeCondition(
+                    DSL.when(
+                        DSL.and(
+                            DSL.eq(DSL.ref("@return"), DSL.value("TWO")),
+                            DSL.eq(DSL.ref("@return"), DSL.value("MyEnum.TWO")),
+                            DSL.eq(
+                                DSL.ref("@return"),
+                                DSL.value("com.datadog.debugger.CapturedSnapshot23$MyEnum.TWO")))),
+                    "@return == 'TWO' && @return == 'MyEnum.TWO' && @return == 'com.datadog.debugger.CapturedSnapshot23$MyEnum.TWO'"))
+            .build();
+    TestSnapshotListener listener = installProbes(CLASS_NAME, probe);
+    Class<?> testClass = compileAndLoadClass(CLASS_NAME);
+    int result = Reflect.onClass(testClass).call("main", "2").get();
+    assertEquals(2, result);
+    Snapshot snapshot = assertOneSnapshot(listener);
+    assertCaptureReturnValue(
+        snapshot.getCaptures().getReturn(),
+        "com.datadog.debugger.CapturedSnapshot23$MyEnum",
+        "TWO");
+  }
+
   @Test
   public void recursiveCapture() throws IOException, URISyntaxException {
     final String CLASS_NAME = "com.datadog.debugger.CapturedSnapshot24";