From aa41dac8d85e5a90e0d7f3aa17801478bbce45e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A5rten=20Kongstad?= <amhk@google.com>
Date: Wed, 22 May 2024 15:13:54 +0200
Subject: [PATCH] check-flagged-apis: make interfaces inherit from
 java/lang/Object

When parsing API signature files, check-flagged-apis relies on
ClassItem.superClass to get the parent class of a class or interface.
That method always returns null for interfaces.

When generating api-versions.xml, metalava marks interface classes as
inheriting from java/lang/Object:

  <class name="android/os/Parcelable" since="1">
    <extends name="java/lang/Object"/>
    [...]
  </class>

This confuses check-flagged-apis when comparing data parsed from both
sources, as the symbol signatures will be identical, but the superclass
entries differ. Work around this by explicitly marking all interfaces
as inheriting from java/lang/Object when parsing API signature files.

Bug: 334870672
Test: atest --host check-flagged-apis-test
Change-Id: Icbb8f7d4c3d4232a083289a778b347e33a0856ab
---
 .../checkflaggedapis/CheckFlaggedApisTest.kt  | 20 +++++++++++++++++++
 .../src/com/android/checkflaggedapis/Main.kt  |  6 +++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/tools/check-flagged-apis/src/com/android/checkflaggedapis/CheckFlaggedApisTest.kt b/tools/check-flagged-apis/src/com/android/checkflaggedapis/CheckFlaggedApisTest.kt
index 111ea91f85..8e285f6216 100644
--- a/tools/check-flagged-apis/src/com/android/checkflaggedapis/CheckFlaggedApisTest.kt
+++ b/tools/check-flagged-apis/src/com/android/checkflaggedapis/CheckFlaggedApisTest.kt
@@ -120,6 +120,26 @@ class CheckFlaggedApisTest {
     assertEquals(expected, actual)
   }
 
+  @Test
+  fun testParseApiSignatureInterfacesInheritFromJavaLangObject() {
+    val apiSignature =
+        """
+          // Signature format: 2.0
+          package android {
+            @FlaggedApi("android.flag.foo") public interface Interface {
+            }
+          }
+        """
+            .trim()
+    val expected =
+        setOf(
+            Pair(
+                Symbol.createClass("android/Interface", "java/lang/Object", setOf()),
+                Flag("android.flag.foo")))
+    val actual = parseApiSignature("in-memory", apiSignature.byteInputStream())
+    assertEquals(expected, actual)
+  }
+
   @Test
   fun testParseFlagValues() {
     val expected: Map<Flag, Boolean> =
diff --git a/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt b/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt
index a277ce815f..1d2440dee8 100644
--- a/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt
+++ b/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt
@@ -205,7 +205,11 @@ internal fun parseApiSignature(path: String, input: InputStream): Set<Pair<Symbo
             val symbol =
                 Symbol.createClass(
                     cls.baselineElementId(),
-                    cls.superClass()?.baselineElementId(),
+                    if (cls.isInterface()) {
+                      "java/lang/Object"
+                    } else {
+                      cls.superClass()?.baselineElementId()
+                    },
                     cls.allInterfaces()
                         .map { it.baselineElementId() }
                         .filter { it != cls.baselineElementId() }