Ignore superMethods from non-Stub parents

In commit 9252e5ce, the logic did not ensure that the super method
belonged to the Stub class, and not any arbitrary method in a parent.

Refactor EnforcePermissionUtils by:
 - Removing isContainedInSubclassOfStub() in favour of containingStub(),
   which returns the Stub PsiClass. Document that this method does not
   mean that the argument is necessary an AIDL-generated method.
 - Update getContainingAidlInterface() to pass the PsiClass to
   findSuperMethod. This ensures that only the Stub class and its
   parents are considered.
 - Drop the check for IINTERFACE_INTERFACE. This is already verified in
   the inner call to isStub().

The same logic is applied manually to EnforcePermissionDetector, as each
condition in getContainingAidlInterface() raises a different error
message.

Add a test to confirm the behaviour of EnforcePermissionDetector.

Bug: 307433823
Test: atest --host AndroidGlobalLintCheckerTest
Test: atest --host AndroidFrameworkLintCheckerTest
Test: enforce_permission_counter
Change-Id: If791b6d8741e5db483589446484bb68061b67b70

3 files changed, 42 insertions, 20 deletions

diff --git a/tools/lint/common/src/main/java/com/google/android/lint/aidl/EnforcePermissionUtils.kt b/tools/lint/common/src/main/java/com/google/android/lint/aidl/EnforcePermissionUtils.kt
index d41fee3fc0dc..24d203fd1116 100644
--- a/tools/lint/common/src/main/java/com/google/android/lint/aidl/EnforcePermissionUtils.kt
+++ b/tools/lint/common/src/main/java/com/google/android/lint/aidl/EnforcePermissionUtils.kt
@@ -24,33 +24,31 @@ import com.intellij.psi.PsiReferenceList
 import org.jetbrains.uast.UMethod
 
 /**
- * Given a UMethod, determine if this method is
- * the entrypoint to an interface generated by AIDL,
- * returning the interface name if so, otherwise returning null
+ * Given a UMethod, determine if this method is the entrypoint to an interface
+ * generated by AIDL, returning the interface name if so, otherwise returning
+ * null
  */
 fun getContainingAidlInterface(context: JavaContext, node: UMethod): String? {
-    if (!isContainedInSubclassOfStub(context, node)) return null
-    for (superMethod in node.findSuperMethods()) {
-        for (extendsInterface in superMethod.containingClass?.extendsList?.referenceElements
-            ?: continue) {
-            if (extendsInterface.qualifiedName == IINTERFACE_INTERFACE) {
-                return superMethod.containingClass?.name
-            }
-        }
-    }
-    return null
+    val containingStub = containingStub(context, node) ?: return null
+    val superMethod = node.findSuperMethods(containingStub)
+    if (superMethod.isEmpty()) return null
+    return containingStub.containingClass?.name
 }
 
-fun isContainedInSubclassOfStub(context: JavaContext, node: UMethod?): Boolean {
+/* Returns the containing Stub class if any. This is not sufficient to infer
+ * that the method itself extends an AIDL generated method. See
+ * getContainingAidlInterface for that purpose.
+ */
+fun containingStub(context: JavaContext, node: UMethod?): PsiClass? {
     var superClass = node?.containingClass?.superClass
     while (superClass != null) {
-        if (isStub(context, superClass)) return true
+        if (isStub(context, superClass)) return superClass
         superClass = superClass.superClass
     }
-    return false
+    return null
 }
 
-fun isStub(context: JavaContext, psiClass: PsiClass?): Boolean {
+private fun isStub(context: JavaContext, psiClass: PsiClass?): Boolean {
     if (psiClass == null) return false
     if (psiClass.name != "Stub") return false
     if (!context.evaluator.isStatic(psiClass)) return false
diff --git a/tools/lint/global/checks/src/main/java/com/google/android/lint/aidl/EnforcePermissionDetector.kt b/tools/lint/global/checks/src/main/java/com/google/android/lint/aidl/EnforcePermissionDetector.kt
index 83b8f163abee..4455a9cda3a8 100644
--- a/tools/lint/global/checks/src/main/java/com/google/android/lint/aidl/EnforcePermissionDetector.kt
+++ b/tools/lint/global/checks/src/main/java/com/google/android/lint/aidl/EnforcePermissionDetector.kt
@@ -168,7 +168,7 @@ class EnforcePermissionDetector : Detector(), SourceCodeScanner {
             annotationInfo.origin == AnnotationOrigin.METHOD) {
             /* Ignore implementations that are not a sub-class of Stub (i.e., Proxy). */
             val uMethod = element as? UMethod ?: return
-            if (!isContainedInSubclassOfStub(context, uMethod)) {
+            if (getContainingAidlInterface(context, uMethod) == null) {
                 return
             }
             val overridingMethod = element.sourcePsi as PsiMethod
@@ -184,7 +184,8 @@ class EnforcePermissionDetector : Detector(), SourceCodeScanner {
             if (context.evaluator.isAbstract(node)) return
             if (!node.hasAnnotation(ANNOTATION_ENFORCE_PERMISSION)) return
 
-            if (!isContainedInSubclassOfStub(context, node)) {
+            val stubClass = containingStub(context, node)
+            if (stubClass == null) {
                 context.report(
                     ISSUE_MISUSING_ENFORCE_PERMISSION,
                     node,
@@ -196,7 +197,7 @@ class EnforcePermissionDetector : Detector(), SourceCodeScanner {
 
             /* Check that we are connected to the super class */
             val overridingMethod = node as PsiMethod
-            val parents = overridingMethod.findSuperMethods()
+            val parents = overridingMethod.findSuperMethods(stubClass)
             if (parents.isEmpty()) {
                 context.report(
                     ISSUE_MISUSING_ENFORCE_PERMISSION,
diff --git a/tools/lint/global/checks/src/test/java/com/google/android/lint/aidl/EnforcePermissionDetectorTest.kt b/tools/lint/global/checks/src/test/java/com/google/android/lint/aidl/EnforcePermissionDetectorTest.kt
index d8afcb977594..2afca05f8130 100644
--- a/tools/lint/global/checks/src/test/java/com/google/android/lint/aidl/EnforcePermissionDetectorTest.kt
+++ b/tools/lint/global/checks/src/test/java/com/google/android/lint/aidl/EnforcePermissionDetectorTest.kt
@@ -176,6 +176,29 @@ class EnforcePermissionDetectorTest : LintDetectorTest() {
                 """.addLineContinuation())
     }
 
+    fun testDetectNoIssuesAnnotationOnNonStubMethod() {
+        lint().files(java(
+            """
+            package test.pkg;
+            public class TestClass43 extends IFooMethod.Stub {
+                public void aRegularMethodNotPartOfStub() {
+                }
+            }
+            """).indented(), java(
+            """
+            package test.pkg;
+            public class TestClass44 extends TestClass43 {
+              @Override
+              public void aRegularMethodNotPartOfStub() {
+              }
+            }
+            """).indented(),
+                *stubs
+        )
+        .run()
+        .expectClean()
+    }
+
     fun testDetectIssuesEmptyAnnotationOnMethod() {
         lint().files(java(
             """