From 87e4d3194c5742a17d4f8029c9ee8f47fe7fa598 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Wed, 11 Mar 2026 18:13:30 -0700
Subject: [PATCH 01/13] fix-desugar-jdk8-libs-support

---
 rules/android_binary/r8.bzl | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/rules/android_binary/r8.bzl b/rules/android_binary/r8.bzl
index 9178f387..c34a51b5 100644
--- a/rules/android_binary/r8.bzl
+++ b/rules/android_binary/r8.bzl
@@ -17,6 +17,7 @@ load("//providers:providers.bzl", "AndroidDexInfo", "AndroidPreDexJarInfo")
 load("//rules:acls.bzl", "acls")
 load("//rules:android_neverlink_aspect.bzl", "StarlarkAndroidNeverlinkInfo")
 load("//rules:common.bzl", "common")
+load("//rules:dex.bzl", "dex")
 load("//rules:java.bzl", "java")
 load("//rules:min_sdk_version.bzl", "min_sdk_version")
 load(
@@ -80,6 +81,7 @@ def process_r8(ctx, validation_ctx, jvm_ctx, packaged_resources_ctx, build_info_
 
     android_jar = get_android_sdk(ctx).android_jar
     proguard_specs = proguard.get_proguard_specs(ctx, packaged_resources_ctx.resource_proguard_config)
+    desugared_lib_config = ctx.file._desugared_lib_config
 
     # Get min SDK version from attribute, manifest_values, or depot floor
     effective_min_sdk = min_sdk_version.DEPOT_FLOOR
@@ -107,12 +109,17 @@ def process_r8(ctx, validation_ctx, jvm_ctx, packaged_resources_ctx, build_info_
     args.add(deploy_jar)  # jar to optimize + desugar + dex
     args.add("--pg-map-output", proguard_mappings_output_file)
 
+    r8_inputs = [android_jar, deploy_jar] + proguard_specs
+    if ctx.fragments.android.desugar_java8_libs and desugared_lib_config:
+        args.add("--desugared-lib", desugared_lib_config)
+        r8_inputs.append(desugared_lib_config)
+
     java.run(
         ctx = ctx,
         host_javabase = common.get_host_javabase(ctx),
         executable = get_android_toolchain(ctx).r8.files_to_run,
         arguments = [args],
-        inputs = depset([android_jar, deploy_jar] + proguard_specs, transitive = [neverlink_jars]),
+        inputs = depset(r8_inputs, transitive = [neverlink_jars]),
         outputs = [dexes_zip, proguard_mappings_output_file],
         mnemonic = "AndroidR8",
         jvm_flags = ["-Xmx8G"],

From 85ffece87e116fc80dc8d53413ba2e922f551929 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Thu, 12 Mar 2026 10:33:32 -0700
Subject: [PATCH 02/13] Update r8.bzl

---
 rules/android_binary/r8.bzl | 1 -
 1 file changed, 1 deletion(-)

diff --git a/rules/android_binary/r8.bzl b/rules/android_binary/r8.bzl
index c34a51b5..53e5b1d3 100644
--- a/rules/android_binary/r8.bzl
+++ b/rules/android_binary/r8.bzl
@@ -17,7 +17,6 @@ load("//providers:providers.bzl", "AndroidDexInfo", "AndroidPreDexJarInfo")
 load("//rules:acls.bzl", "acls")
 load("//rules:android_neverlink_aspect.bzl", "StarlarkAndroidNeverlinkInfo")
 load("//rules:common.bzl", "common")
-load("//rules:dex.bzl", "dex")
 load("//rules:java.bzl", "java")
 load("//rules:min_sdk_version.bzl", "min_sdk_version")
 load(

From 8640a29b468399ab8c901be3b45fa5b5305d6dd9 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Wed, 18 Mar 2026 09:13:47 -0700
Subject: [PATCH 03/13] Add tests

---
 .../rules/android_binary/r8_integration/BUILD | 10 +++
 .../java/com/desugaring/AndroidManifest.xml   | 19 +++++
 .../r8_integration/java/com/desugaring/BUILD  | 16 ++++
 .../com/desugaring/DesugaringActivity.java    | 17 ++++
 .../java/com/desugaring/DurationUser.java     | 18 +++++
 .../java/com/desugaring/proguard.cfg          |  2 +
 .../desugaring/res/layout/activity_main.xml   |  5 ++
 .../com/desugaring/res/values/strings.xml     |  4 +
 .../r8_integration/r8_desugaring_test.py      | 80 +++++++++++++++++++
 9 files changed, 171 insertions(+)
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/BUILD
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml
 create mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml
 create mode 100644 test/rules/android_binary/r8_integration/r8_desugaring_test.py

diff --git a/test/rules/android_binary/r8_integration/BUILD b/test/rules/android_binary/r8_integration/BUILD
index d3f4325f..dc2ca194 100644
--- a/test/rules/android_binary/r8_integration/BUILD
+++ b/test/rules/android_binary/r8_integration/BUILD
@@ -24,3 +24,13 @@ build_test(
     name = "android_binary_with_neverlink_deps_build_test",
     targets = ["//test/rules/android_binary/r8_integration/java/com/neverlink:android_binary_with_neverlink_deps"],
 )
+
+py_test(
+    name = "r8_desugaring_test",
+    srcs = ["r8_desugaring_test.py"],
+    args = ["$(location @androidsdk//:dexdump)"],
+    data = [
+        "//test/rules/android_binary/r8_integration/java/com/desugaring:desugaring_app_r8",
+        "@androidsdk//:dexdump",
+    ],
+)
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml b/test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml
new file mode 100644
index 00000000..67e5eae7
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.desugaring" >
+
+    <uses-sdk
+        android:minSdkVersion="28"
+        android:targetSdkVersion="34" />
+
+    <application>
+        <activity
+            android:name="com.desugaring.DesugaringActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/BUILD b/test/rules/android_binary/r8_integration/java/com/desugaring/BUILD
new file mode 100644
index 00000000..33409397
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/BUILD
@@ -0,0 +1,16 @@
+load("//rules:rules.bzl", "android_binary", "android_library")
+
+android_library(
+    name = "duration_lib",
+    srcs = ["DurationUser.java"],
+)
+
+android_binary(
+    name = "desugaring_app_r8",
+    srcs = ["DesugaringActivity.java"],
+    manifest = "AndroidManifest.xml",
+    proguard_specs = ["proguard.cfg"],
+    resource_files = glob(["res/**"]),
+    visibility = ["//test/rules/android_binary/r8_integration:__pkg__"],
+    deps = [":duration_lib"],
+)
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java b/test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java
new file mode 100644
index 00000000..d9c42a68
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java
@@ -0,0 +1,17 @@
+package com.desugaring;
+
+import android.app.Activity;
+import android.os.Bundle;
+import java.time.Duration;
+
+/** Activity that exercises Duration.toSeconds() to test core library desugaring. */
+public class DesugaringActivity extends Activity {
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        // Force the compiler to retain the call to DurationUser.getSeconds
+        long seconds = DurationUser.getSeconds(Duration.ofMinutes(5));
+        setTitle("Seconds: " + seconds);
+    }
+}
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java b/test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java
new file mode 100644
index 00000000..2c63bec7
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java
@@ -0,0 +1,18 @@
+package com.desugaring;
+
+import java.time.Duration;
+
+/**
+ * A class that uses Duration.toSeconds(), which was added in API 31.
+ * This simulates a third-party library (like Google Nav SDK) that calls
+ * methods not available on all supported API levels.
+ *
+ * Without core library desugaring, this causes NoSuchMethodError on
+ * API 26-30 devices.
+ */
+public class DurationUser {
+    public static long getSeconds(Duration duration) {
+        // Duration.toSeconds() requires API 31+
+        return duration.toSeconds();
+    }
+}
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg b/test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg
new file mode 100644
index 00000000..7ef29b7a
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg
@@ -0,0 +1,2 @@
+-dontobfuscate
+-keep class com.desugaring.DurationUser { *; }
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml b/test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml
new file mode 100644
index 00000000..bce65f74
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+</LinearLayout>
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml b/test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml
new file mode 100644
index 00000000..a5efdad9
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">Desugaring Test</string>
+</resources>
diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_test.py b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
new file mode 100644
index 00000000..a990b2c6
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
@@ -0,0 +1,80 @@
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests that R8 properly applies core library desugaring.
+
+Verifies that methods added after API 26 (like Duration.toSeconds() from
+API 31) are retargeted to their backported implementations when R8 processes
+an android_binary with core library desugaring enabled.
+"""
+
+import os
+import subprocess
+import sys
+import unittest
+import zipfile
+
+
+class R8DesugaringTest(unittest.TestCase):
+    """Tests R8 core library desugaring integration."""
+
+    def _get_dexdump_output(self, apk_name):
+        tmp = os.environ["TEST_TMPDIR"]
+        apk_directory = "test/rules/android_binary/r8_integration/java/com/desugaring"
+        apk_path = os.path.join(apk_directory, apk_name)
+        apk_tmp = os.path.join(tmp, apk_name)
+
+        all_output = []
+        with zipfile.ZipFile(apk_path) as zf:
+            for name in zf.namelist():
+                if name.endswith(".dex"):
+                    zf.extract(name, apk_tmp)
+                    dex_path = os.path.join(apk_tmp, name)
+                    proc = subprocess.run(
+                        [dexdump, "-d", dex_path],
+                        stdout=subprocess.PIPE,
+                        stderr=subprocess.PIPE,
+                        check=True,
+                    )
+                    all_output.append(proc.stdout.decode(errors="replace"))
+
+        return "\n".join(all_output)
+
+    def test_duration_to_seconds_is_desugared(self):
+        """Duration.toSeconds() (API 31) must not appear as a raw call in the DEX."""
+        output = self._get_dexdump_output("desugaring_app_r8.apk")
+
+        self.assertNotIn(
+            "Ljava/time/Duration;.toSeconds:()J",
+            output,
+            "Duration.toSeconds() was NOT desugared. This method requires API 31 "
+            "and will cause NoSuchMethodError on API 28-30 devices. "
+            "R8 must be passed --desugared-lib to retarget this call.",
+        )
+
+    def test_desugared_duration_class_present(self):
+        """The desugared library runtime must be included in the APK."""
+        output = self._get_dexdump_output("desugaring_app_r8.apk")
+
+        # The DurationUser class should still be in the DEX (kept by proguard rules)
+        self.assertIn(
+            "Class descriptor  : 'Lcom/desugaring/DurationUser;'",
+            output,
+            "DurationUser class not found in DEX output",
+        )
+
+
+if __name__ == "__main__":
+    dexdump = sys.argv.pop()
+    unittest.main(argv=None)

From 08df61bc68adfe73a99cf1c6ea61316d35a94510 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Wed, 18 Mar 2026 09:21:12 -0700
Subject: [PATCH 04/13] Update .bazelrc with --desugar_java8_libs

---
 .bazelrc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.bazelrc b/.bazelrc
index faa25c25..8a3a2950 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -28,3 +28,4 @@ build:windows --define=protobuf_allow_msvc=true
 
 common --enable_platform_specific_config
 
+common --desugar_java8_libs

From bfea0aa76d1ad48e00485e0fd5a4c093d8998433 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Wed, 18 Mar 2026 09:29:19 -0700
Subject: [PATCH 05/13] Test cleanup

---
 .../r8_integration/r8_desugaring_test.py      | 81 ++++++++-----------
 1 file changed, 33 insertions(+), 48 deletions(-)

diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_test.py b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
index a990b2c6..979fe8c3 100644
--- a/test/rules/android_binary/r8_integration/r8_desugaring_test.py
+++ b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
@@ -12,13 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Tests that R8 properly applies core library desugaring.
-
-Verifies that methods added after API 26 (like Duration.toSeconds() from
-API 31) are retargeted to their backported implementations when R8 processes
-an android_binary with core library desugaring enabled.
-"""
-
 import os
 import subprocess
 import sys
@@ -27,54 +20,46 @@
 
 
 class R8DesugaringTest(unittest.TestCase):
-    """Tests R8 core library desugaring integration."""
+  """Tests R8 core library desugaring integration."""
 
-    def _get_dexdump_output(self, apk_name):
-        tmp = os.environ["TEST_TMPDIR"]
-        apk_directory = "test/rules/android_binary/r8_integration/java/com/desugaring"
-        apk_path = os.path.join(apk_directory, apk_name)
-        apk_tmp = os.path.join(tmp, apk_name)
+  def _get_dexdump_output(self, apk_name):
+    tmp = os.environ["TEST_TMPDIR"]
+    apk_directory = "test/rules/android_binary/r8_integration/java/com/desugaring"
+    apk_path = os.path.join(apk_directory, apk_name)
+    apk_tmp = os.path.join(tmp, apk_name)
 
-        all_output = []
-        with zipfile.ZipFile(apk_path) as zf:
-            for name in zf.namelist():
-                if name.endswith(".dex"):
-                    zf.extract(name, apk_tmp)
-                    dex_path = os.path.join(apk_tmp, name)
-                    proc = subprocess.run(
-                        [dexdump, "-d", dex_path],
-                        stdout=subprocess.PIPE,
-                        stderr=subprocess.PIPE,
-                        check=True,
-                    )
-                    all_output.append(proc.stdout.decode(errors="replace"))
+    with zipfile.ZipFile(apk_path) as zf:
+      zf.extract("classes.dex", apk_tmp)
 
-        return "\n".join(all_output)
+    dexdump_proc = subprocess.run(
+        [dexdump, "-d", os.path.join(apk_tmp, "classes.dex")],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        check=True,
+    )
+    return str(dexdump_proc.stdout)
 
-    def test_duration_to_seconds_is_desugared(self):
-        """Duration.toSeconds() (API 31) must not appear as a raw call in the DEX."""
-        output = self._get_dexdump_output("desugaring_app_r8.apk")
+  def test_duration_to_seconds_is_desugared(self):
+    output = self._get_dexdump_output("desugaring_app_r8.apk")
 
-        self.assertNotIn(
-            "Ljava/time/Duration;.toSeconds:()J",
-            output,
-            "Duration.toSeconds() was NOT desugared. This method requires API 31 "
-            "and will cause NoSuchMethodError on API 28-30 devices. "
-            "R8 must be passed --desugared-lib to retarget this call.",
-        )
+    # Duration.toSeconds() (API 31) must not appear as a raw call in the DEX.
+    # If present, R8 was not passed --desugared-lib and the call will cause
+    # NoSuchMethodError on API 28-30 devices.
+    self.assertNotIn(
+        "Ljava/time/Duration;.toSeconds:()J",
+        output,
+    )
 
-    def test_desugared_duration_class_present(self):
-        """The desugared library runtime must be included in the APK."""
-        output = self._get_dexdump_output("desugaring_app_r8.apk")
+  def test_desugared_duration_class_present(self):
+    output = self._get_dexdump_output("desugaring_app_r8.apk")
 
-        # The DurationUser class should still be in the DEX (kept by proguard rules)
-        self.assertIn(
-            "Class descriptor  : 'Lcom/desugaring/DurationUser;'",
-            output,
-            "DurationUser class not found in DEX output",
-        )
+    # The DurationUser class should still be in the DEX (kept by proguard rules)
+    self.assertIn(
+        "Class descriptor  : 'Lcom/desugaring/DurationUser;'",
+        output,
+    )
 
 
 if __name__ == "__main__":
-    dexdump = sys.argv.pop()
-    unittest.main(argv=None)
+  dexdump = sys.argv.pop()
+  unittest.main(argv=None)

From 8288b12500030cf774d2d9ad000b52ad74c06e45 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Thu, 19 Mar 2026 06:58:09 -0700
Subject: [PATCH 06/13] More fixes

---
 test/rules/android_binary/r8_integration/r8_desugaring_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_test.py b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
index 979fe8c3..49a06261 100644
--- a/test/rules/android_binary/r8_integration/r8_desugaring_test.py
+++ b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
@@ -37,7 +37,7 @@ def _get_dexdump_output(self, apk_name):
         stderr=subprocess.PIPE,
         check=True,
     )
-    return str(dexdump_proc.stdout)
+    return dexdump_proc.stdout.decode()
 
   def test_duration_to_seconds_is_desugared(self):
     output = self._get_dexdump_output("desugaring_app_r8.apk")

From 22cb503be16fd9f3e3e0eed64fee9ac9536a8f56 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 11:00:44 -0700
Subject: [PATCH 07/13] Add more tests to cover edge cases

---
 .../r8_integration/r8_desugaring_test.py      | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_test.py b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
index 49a06261..87a33617 100644
--- a/test/rules/android_binary/r8_integration/r8_desugaring_test.py
+++ b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
@@ -39,6 +39,27 @@ def _get_dexdump_output(self, apk_name):
     )
     return dexdump_proc.stdout.decode()
 
+  def _get_all_dex_output(self, apk_name):
+    """Get dexdump output for ALL dex files in the APK (without disassembly)."""
+    tmp = os.environ["TEST_TMPDIR"]
+    apk_directory = "test/rules/android_binary/r8_integration/java/com/desugaring"
+    apk_path = os.path.join(apk_directory, apk_name)
+    apk_tmp = os.path.join(tmp, apk_name + "_all")
+
+    all_output = ""
+    with zipfile.ZipFile(apk_path) as zf:
+      dex_files = sorted(name for name in zf.namelist() if name.endswith(".dex"))
+      for dex_file in dex_files:
+        zf.extract(dex_file, apk_tmp)
+        dexdump_proc = subprocess.run(
+            [dexdump, os.path.join(apk_tmp, dex_file)],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            check=True,
+        )
+        all_output += dexdump_proc.stdout.decode(errors="replace")
+    return all_output
+
   def test_duration_to_seconds_is_desugared(self):
     output = self._get_dexdump_output("desugaring_app_r8.apk")
 
@@ -59,6 +80,24 @@ def test_desugared_duration_class_present(self):
         output,
     )
 
+  def test_desugared_library_classes_present(self):
+    """Desugared library backport classes (j$.*) must be in the APK.
+
+    When R8 rewrites java.* API calls to j$.* backport calls via
+    --desugared-lib, the j$.* implementation classes must be compiled into DEX
+    and included in the APK. Without them, the app crashes at runtime with:
+      NoClassDefFoundError: Failed resolution of: Lj$/...;
+    (e.g. j$/net/URLEncoder, j$/time/Duration, etc.)
+    """
+    output = self._get_all_dex_output("desugaring_app_r8.apk")
+
+    # There must be at least one j$.* class definition in the combined DEX
+    # output. These are the desugared library backport implementations.
+    self.assertRegex(
+        output,
+        r"Class descriptor\s+:\s+'Lj\$/",
+    )
+
 
 if __name__ == "__main__":
   dexdump = sys.argv.pop()

From a3d242d5a87a57f2b7bb2bb683dcbb1a2593a431 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 11:01:06 -0700
Subject: [PATCH 08/13] And push the actual solution

---
 rules/android_binary/r8.bzl | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/rules/android_binary/r8.bzl b/rules/android_binary/r8.bzl
index 53e5b1d3..9c8c0dbe 100644
--- a/rules/android_binary/r8.bzl
+++ b/rules/android_binary/r8.bzl
@@ -17,6 +17,7 @@ load("//providers:providers.bzl", "AndroidDexInfo", "AndroidPreDexJarInfo")
 load("//rules:acls.bzl", "acls")
 load("//rules:android_neverlink_aspect.bzl", "StarlarkAndroidNeverlinkInfo")
 load("//rules:common.bzl", "common")
+load("//rules:dex.bzl", _dex = "dex")
 load("//rules:java.bzl", "java")
 load("//rules:min_sdk_version.bzl", "min_sdk_version")
 load(
@@ -125,9 +126,28 @@ def process_r8(ctx, validation_ctx, jvm_ctx, packaged_resources_ctx, build_info_
         progress_message = "R8 Optimizing, Desugaring, and Dexing %{label}",
     )
 
+    # When R8 runs with --desugared-lib, it rewrites java.* API calls to j$.*
+    # backport references, but does NOT include the j$.* implementation classes
+    # in its output. Append the prebuilt desugared library DEX so the j$.*
+    # classes are available at runtime.
+    if ctx.fragments.android.desugar_java8_libs and desugared_lib_config:
+        final_classes_dex_zip = ctx.actions.declare_file(ctx.label.name + "_final_dexes.zip")
+        java8_legacy_dex = utils.only(
+            get_android_toolchain(ctx).java8_legacy_dex.files.to_list(),
+        )
+        _dex.append_desugar_dexes(
+            ctx,
+            output = final_classes_dex_zip,
+            input = dexes_zip,
+            dexes = [java8_legacy_dex],
+            dex_zips_merger = get_android_toolchain(ctx).dex_zips_merger.files_to_run,
+        )
+    else:
+        final_classes_dex_zip = dexes_zip
+
     android_dex_info = AndroidDexInfo(
         deploy_jar = deploy_jar,
-        final_classes_dex_zip = dexes_zip,
+        final_classes_dex_zip = final_classes_dex_zip,
         # R8 preserves the Java resources (i.e. non-Java-class files) in its output zip, so no need
         # to provide a Java resources zip.
         java_resource_jar = None,
@@ -136,7 +156,7 @@ def process_r8(ctx, validation_ctx, jvm_ctx, packaged_resources_ctx, build_info_
     return ProviderInfo(
         name = "r8_ctx",
         value = struct(
-            final_classes_dex_zip = dexes_zip,
+            final_classes_dex_zip = final_classes_dex_zip,
             dex_info = android_dex_info,
             providers = [
                 android_dex_info,

From 6ba19ed8139030f2e3e24bdf015844026599e405 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 12:20:02 -0700
Subject: [PATCH 09/13] Build out some better integration tests

---
 .bazelrc                                      |   2 -
 BUILD                                         |   2 +
 rules/BUILD                                   |   1 +
 .../rules/android_binary/r8_integration/BUILD |  38 ++-
 .../r8_integration/r8_desugaring_helper.sh    | 236 ++++++++++++++++++
 .../r8_desugaring_integration_test.sh         |  86 +++++++
 .../r8_integration/r8_desugaring_test.py      | 104 --------
 7 files changed, 357 insertions(+), 112 deletions(-)
 create mode 100755 test/rules/android_binary/r8_integration/r8_desugaring_helper.sh
 create mode 100755 test/rules/android_binary/r8_integration/r8_desugaring_integration_test.sh
 delete mode 100644 test/rules/android_binary/r8_integration/r8_desugaring_test.py

diff --git a/.bazelrc b/.bazelrc
index 8a3a2950..d0ec2874 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -27,5 +27,3 @@ common:windows --host_per_file_copt=external/.*@/w
 build:windows --define=protobuf_allow_msvc=true
 
 common --enable_platform_specific_config
-
-common --desugar_java8_libs
diff --git a/BUILD b/BUILD
index 5cd188c2..b17116fd 100644
--- a/BUILD
+++ b/BUILD
@@ -6,6 +6,8 @@ package(
     default_visibility = ["//visibility:public"],
 )
 
+exports_files(["MODULE.bazel"])
+
 license(
     name = "license",
     package_name = "bazelbuild/rules_android",
diff --git a/rules/BUILD b/rules/BUILD
index b0d524b1..e924b6b7 100644
--- a/rules/BUILD
+++ b/rules/BUILD
@@ -109,6 +109,7 @@ bzl_library(
     visibility = [
         "//mobile_install:__pkg__",
         "//stardoc:__pkg__",
+        "//test/rules/android_binary/r8_integration:__pkg__",
         "//test/rules/android_sdk_repository:__pkg__",
     ],
     deps = [
diff --git a/test/rules/android_binary/r8_integration/BUILD b/test/rules/android_binary/r8_integration/BUILD
index dc2ca194..5cc853f3 100644
--- a/test/rules/android_binary/r8_integration/BUILD
+++ b/test/rules/android_binary/r8_integration/BUILD
@@ -1,5 +1,11 @@
+load("@bazel_binaries//:defs.bzl", "bazel_binaries")
 load("@bazel_skylib//rules:build_test.bzl", "build_test")
+load(
+    "@rules_bazel_integration_test//bazel_integration_test:defs.bzl",
+    "script_test",
+)
 load("@rules_python//python:py_test.bzl", "py_test")
+load("@rules_shell//shell:sh_library.bzl", "sh_library")
 load(":test.bzl", "r8_neverlink_deps_test")
 
 py_test(
@@ -25,12 +31,32 @@ build_test(
     targets = ["//test/rules/android_binary/r8_integration/java/com/neverlink:android_binary_with_neverlink_deps"],
 )
 
-py_test(
-    name = "r8_desugaring_test",
-    srcs = ["r8_desugaring_test.py"],
-    args = ["$(location @androidsdk//:dexdump)"],
+sh_library(
+    name = "r8_desugaring_helper",
+    testonly = True,
+    srcs = ["r8_desugaring_helper.sh"],
     data = [
-        "//test/rules/android_binary/r8_integration/java/com/desugaring:desugaring_app_r8",
-        "@androidsdk//:dexdump",
+        "//:MODULE.bazel",
+        "//rules:bzl",
+    ],
+    visibility = ["//visibility:private"],
+    deps = [
+        "//test/bashunit",
+        "@rules_shell//shell/runfiles",
+    ],
+)
+
+script_test(
+    name = "r8_desugaring_integration_test",
+    size = "enormous",
+    srcs = ["r8_desugaring_integration_test.sh"],
+    bazel_binaries = bazel_binaries,
+    bazel_version = bazel_binaries.versions.current,
+    tags = ["manual"],
+    timeout = "eternal",
+    deps = [
+        ":r8_desugaring_helper",
+        "//test/bashunit",
+        "@rules_shell//shell/runfiles",
     ],
 )
diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_helper.sh b/test/rules/android_binary/r8_integration/r8_desugaring_helper.sh
new file mode 100755
index 00000000..3ef49123
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/r8_desugaring_helper.sh
@@ -0,0 +1,236 @@
+#!/bin/bash
+#
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Helper functions for R8 desugaring integration tests.
+
+# --- begin runfiles.bash initialization v2 ---
+# Copy-pasted from the Bazel Bash runfiles library v2.
+set -uo pipefail; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$0.runfiles/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+# --- end runfiles.bash initialization v2 ---
+
+source "$(rlocation rules_android/test/bashunit/unittest.bash)" || \
+  (echo >&2 "Failed to locate bashunit.sh" && exit 1)
+
+_WORKSPACE_INITIALIZED=false
+
+# Resolve the real filesystem path of the rules_android source tree.
+function get_rules_android_path() {
+  local module_bazel="$(rlocation rules_android/MODULE.bazel)"
+  if [[ -z "${module_bazel}" || ! -f "${module_bazel}" ]]; then
+    fail "Failed to locate rules_android MODULE.bazel"
+  fi
+  local real_path
+  real_path="$(python3 -c "import os; print(os.path.realpath('${module_bazel}'))")"
+  dirname "${real_path}"
+}
+
+# set_up is called before each test by bashunit. We only initialize the
+# workspace once since the inner Bazel build is expensive. Subsequent tests
+# reuse the same workspace and inner Bazel server.
+function set_up() {
+  if [[ "${_WORKSPACE_INITIALIZED}" == "true" ]]; then
+    return
+  fi
+  _WORKSPACE_INITIALIZED=true
+
+  # Clean out the workspace.
+  rm -rf *
+
+  set_up_workspace
+  create_desugaring_app
+}
+
+function set_up_workspace() {
+  local rules_dir="$(get_rules_android_path)"
+
+  # Find the Android SDK path from environment.
+  local sdk_path="${ANDROID_HOME:-${ANDROID_SDK_ROOT:-}}"
+  if [[ -z "${sdk_path}" ]]; then
+    fail "ANDROID_HOME or ANDROID_SDK_ROOT must be set"
+  fi
+
+  cat > MODULE.bazel <<EOF
+module(name = "desugaring_test")
+
+bazel_dep(name = "rules_java", version = "9.3.0")
+bazel_dep(name = "bazel_skylib", version = "1.8.1")
+bazel_dep(name = "rules_android", version = "0.7.1")
+
+local_path_override(
+    module_name = "rules_android",
+    path = "${rules_dir}",
+)
+
+remote_android_extensions = use_extension(
+    "@rules_android//bzlmod_extensions:android_extensions.bzl",
+    "remote_android_tools_extensions")
+use_repo(remote_android_extensions, "android_tools")
+
+android_sdk_repository_extension = use_extension(
+    "@rules_android//rules/android_sdk_repository:rule.bzl",
+    "android_sdk_repository_extension")
+android_sdk_repository_extension.configure(path = "${sdk_path}")
+use_repo(android_sdk_repository_extension, "androidsdk")
+
+register_toolchains("@androidsdk//:sdk-toolchain", "@androidsdk//:all")
+EOF
+
+  cat > .bazelrc <<EOF
+common --action_env=ANDROID_HOME=${sdk_path}
+common --noenable_workspace
+common --enable_bzlmod
+common --java_language_version=17
+common --java_runtime_version=17
+common --tool_java_language_version=17
+common --tool_java_runtime_version=17
+common --enable_platform_specific_config
+common:linux --cxxopt=-std=c++17
+common:linux --host_cxxopt=-std=c++17
+common:macos --cxxopt=-std=c++17
+common:macos --host_cxxopt=-std=c++17
+common:windows --cxxopt=/std:c++17
+common:windows --host_cxxopt=/std:c++17
+common:linux --per_file_copt=external/.*@-w
+common:linux --host_per_file_copt=external/.*@-w
+common:macos --per_file_copt=external/.*@-w
+common:macos --host_per_file_copt=external/.*@-w
+common:windows --per_file_copt=external/.*@/w
+common:windows --host_per_file_copt=external/.*@/w
+common --repositories_without_autoloads=bazel_features_version,bazel_features_globals,cc_compatibility_proxy
+EOF
+}
+
+function create_desugaring_app() {
+  mkdir -p app/res/layout app/res/values
+
+  cat > app/BUILD <<'EOF'
+load("@rules_android//rules:rules.bzl", "android_binary")
+
+android_binary(
+    name = "desugaring_app",
+    srcs = [
+        "DesugaringActivity.java",
+        "DurationUser.java",
+    ],
+    manifest = "AndroidManifest.xml",
+    proguard_specs = ["proguard.cfg"],
+    resource_files = glob(["res/**"]),
+)
+EOF
+
+  cat > app/AndroidManifest.xml <<'EOF'
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.desugaring.test">
+    <application>
+        <activity android:name=".DesugaringActivity"
+                  android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>
+EOF
+
+  cat > app/DesugaringActivity.java <<'EOF'
+package com.desugaring.test;
+
+import android.app.Activity;
+import android.os.Bundle;
+import java.time.Duration;
+
+public class DesugaringActivity extends Activity {
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        long seconds = DurationUser.getSeconds(Duration.ofMinutes(5));
+        setTitle("Seconds: " + seconds);
+    }
+}
+EOF
+
+  cat > app/DurationUser.java <<'EOF'
+package com.desugaring.test;
+
+import java.time.Duration;
+
+public class DurationUser {
+    public static long getSeconds(Duration duration) {
+        return duration.toSeconds();
+    }
+}
+EOF
+
+  cat > app/proguard.cfg <<'EOF'
+-dontobfuscate
+-keep class com.desugaring.test.DurationUser { *; }
+-keep class com.desugaring.test.DesugaringActivity { *; }
+EOF
+
+  cat > app/res/layout/activity_main.xml <<'EOF'
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />
+EOF
+
+  cat > app/res/values/strings.xml <<'EOF'
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">DesugarTest</string>
+</resources>
+EOF
+}
+
+# Build the desugaring app with extra Bazel flags.
+# Usage: build_desugaring_app [--desugar_java8_libs | --nodesugar_java8_libs]
+function build_desugaring_app() {
+  "${BIT_BAZEL_BINARY}" build "$@" -- //app:desugaring_app >& $TEST_log || \
+    fail "Failed to build desugaring app"
+}
+
+# Returns 0 if any dex in the APK contains a string matching the given pattern.
+# Usage: apk_dex_contains <grep_pattern>
+function apk_dex_contains() {
+  local pattern="$1"
+  local apk_path="bazel-bin/app/desugaring_app.apk"
+  if [[ ! -f "${apk_path}" ]]; then
+    echo "APK not found at ${apk_path}" >&2
+    return 1
+  fi
+
+  local tmpdir=$(mktemp -d)
+  unzip -o "${apk_path}" '*.dex' -d "${tmpdir}" > /dev/null 2>&1
+
+  local found=false
+  for dex in "${tmpdir}"/classes*.dex; do
+    if [[ -f "${dex}" ]] && strings "${dex}" | grep -q "${pattern}"; then
+      found=true
+      break
+    fi
+  done
+
+  rm -rf "${tmpdir}"
+  [[ "${found}" == "true" ]]
+}
diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_integration_test.sh b/test/rules/android_binary/r8_integration/r8_desugaring_integration_test.sh
new file mode 100755
index 00000000..0fe90e72
--- /dev/null
+++ b/test/rules/android_binary/r8_integration/r8_desugaring_integration_test.sh
@@ -0,0 +1,86 @@
+#!/bin/bash
+#
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Integration tests for R8 desugaring with and without --desugar_java8_libs.
+#
+# These tests verify that:
+# 1. When --desugar_java8_libs is enabled, R8 rewrites java.* calls to j$.*
+#    backports AND the j$.* implementation classes are included in the APK.
+# 2. When --nodesugar_java8_libs is set, no j$.* classes appear in the APK
+#    and java.* calls remain as-is.
+# 3. DurationUser is retained in both cases (proguard keep rule).
+
+# --- begin runfiles.bash initialization v2 ---
+# Copy-pasted from the Bazel Bash runfiles library v2.
+set -uo pipefail; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$0.runfiles/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+# --- end runfiles.bash initialization v2 ---
+
+source "$(rlocation rules_android/test/bashunit/unittest.bash)" || \
+  (echo >&2 "Failed to locate bashunit.sh" && exit 1)
+
+source "$(rlocation rules_android/test/rules/android_binary/r8_integration/r8_desugaring_helper.sh)" || \
+  (echo >&2 "Failed to locate r8_desugaring_helper.sh" && exit 1)
+
+# Test: with --desugar_java8_libs enabled, R8 desugars java.time APIs and the
+# backport implementation classes (j$.*) are included in the APK.
+function test_desugaring_enabled() {
+  build_desugaring_app --desugar_java8_libs
+
+  # DurationUser must be retained by proguard keep rules.
+  apk_dex_contains 'Lcom/desugaring/test/DurationUser;' || \
+    fail "DurationUser class not found in DEX"
+
+  # Duration.toSeconds() (API 31) must be desugared: the raw java.time
+  # invocation is rewritten to a j$.time backport, so the original
+  # method reference should not appear in the constant pool.
+  if apk_dex_contains 'java/time/Duration;.*toSeconds'; then
+    fail "Expected Duration.toSeconds() to be desugared but raw java/time reference found"
+  fi
+
+  # The j$.* backport implementation classes must be present. Without them
+  # the app crashes at runtime with NoClassDefFoundError (e.g. j$/net/URLEncoder).
+  apk_dex_contains 'Lj\$/' || \
+    fail "Expected j\$.* desugared library classes in the APK"
+}
+
+# Test: with --nodesugar_java8_libs, R8 does not rewrite java.* references
+# and no desugared library DEX is appended.
+function test_desugaring_disabled() {
+  build_desugaring_app --nodesugar_java8_libs
+
+  # DurationUser must still be retained regardless of the desugaring flag.
+  apk_dex_contains 'Lcom/desugaring/test/DurationUser;' || \
+    fail "DurationUser class not found in DEX"
+
+  # Without desugaring, java.time.Duration.toSeconds() remains as a direct
+  # call in the DEX. (It will crash on API < 31 devices, but the reference
+  # should be present.)
+  apk_dex_contains 'java/time/Duration' || \
+    fail "Expected raw java/time/Duration reference when desugaring is disabled"
+
+  # No j$.* classes should be present.
+  if apk_dex_contains 'Lj\$/'; then
+    fail "Unexpected j\$.* desugared library classes when desugaring is disabled"
+  fi
+}
+
+run_suite "R8 desugaring integration tests"
diff --git a/test/rules/android_binary/r8_integration/r8_desugaring_test.py b/test/rules/android_binary/r8_integration/r8_desugaring_test.py
deleted file mode 100644
index 87a33617..00000000
--- a/test/rules/android_binary/r8_integration/r8_desugaring_test.py
+++ /dev/null
@@ -1,104 +0,0 @@
-# Copyright 2024 The Bazel Authors. All rights reserved.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-import os
-import subprocess
-import sys
-import unittest
-import zipfile
-
-
-class R8DesugaringTest(unittest.TestCase):
-  """Tests R8 core library desugaring integration."""
-
-  def _get_dexdump_output(self, apk_name):
-    tmp = os.environ["TEST_TMPDIR"]
-    apk_directory = "test/rules/android_binary/r8_integration/java/com/desugaring"
-    apk_path = os.path.join(apk_directory, apk_name)
-    apk_tmp = os.path.join(tmp, apk_name)
-
-    with zipfile.ZipFile(apk_path) as zf:
-      zf.extract("classes.dex", apk_tmp)
-
-    dexdump_proc = subprocess.run(
-        [dexdump, "-d", os.path.join(apk_tmp, "classes.dex")],
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
-        check=True,
-    )
-    return dexdump_proc.stdout.decode()
-
-  def _get_all_dex_output(self, apk_name):
-    """Get dexdump output for ALL dex files in the APK (without disassembly)."""
-    tmp = os.environ["TEST_TMPDIR"]
-    apk_directory = "test/rules/android_binary/r8_integration/java/com/desugaring"
-    apk_path = os.path.join(apk_directory, apk_name)
-    apk_tmp = os.path.join(tmp, apk_name + "_all")
-
-    all_output = ""
-    with zipfile.ZipFile(apk_path) as zf:
-      dex_files = sorted(name for name in zf.namelist() if name.endswith(".dex"))
-      for dex_file in dex_files:
-        zf.extract(dex_file, apk_tmp)
-        dexdump_proc = subprocess.run(
-            [dexdump, os.path.join(apk_tmp, dex_file)],
-            stdout=subprocess.PIPE,
-            stderr=subprocess.PIPE,
-            check=True,
-        )
-        all_output += dexdump_proc.stdout.decode(errors="replace")
-    return all_output
-
-  def test_duration_to_seconds_is_desugared(self):
-    output = self._get_dexdump_output("desugaring_app_r8.apk")
-
-    # Duration.toSeconds() (API 31) must not appear as a raw call in the DEX.
-    # If present, R8 was not passed --desugared-lib and the call will cause
-    # NoSuchMethodError on API 28-30 devices.
-    self.assertNotIn(
-        "Ljava/time/Duration;.toSeconds:()J",
-        output,
-    )
-
-  def test_desugared_duration_class_present(self):
-    output = self._get_dexdump_output("desugaring_app_r8.apk")
-
-    # The DurationUser class should still be in the DEX (kept by proguard rules)
-    self.assertIn(
-        "Class descriptor  : 'Lcom/desugaring/DurationUser;'",
-        output,
-    )
-
-  def test_desugared_library_classes_present(self):
-    """Desugared library backport classes (j$.*) must be in the APK.
-
-    When R8 rewrites java.* API calls to j$.* backport calls via
-    --desugared-lib, the j$.* implementation classes must be compiled into DEX
-    and included in the APK. Without them, the app crashes at runtime with:
-      NoClassDefFoundError: Failed resolution of: Lj$/...;
-    (e.g. j$/net/URLEncoder, j$/time/Duration, etc.)
-    """
-    output = self._get_all_dex_output("desugaring_app_r8.apk")
-
-    # There must be at least one j$.* class definition in the combined DEX
-    # output. These are the desugared library backport implementations.
-    self.assertRegex(
-        output,
-        r"Class descriptor\s+:\s+'Lj\$/",
-    )
-
-
-if __name__ == "__main__":
-  dexdump = sys.argv.pop()
-  unittest.main(argv=None)

From ce04ea54ac8cfad818f62c2b80859000012dc808 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 12:48:18 -0700
Subject: [PATCH 10/13] Remove test/rules/android_binary/r8_integration

---
 .../java/com/desugaring/AndroidManifest.xml   | 19 -------------------
 .../r8_integration/java/com/desugaring/BUILD  | 16 ----------------
 .../com/desugaring/DesugaringActivity.java    | 17 -----------------
 .../java/com/desugaring/DurationUser.java     | 18 ------------------
 .../java/com/desugaring/proguard.cfg          |  2 --
 .../desugaring/res/layout/activity_main.xml   |  5 -----
 .../com/desugaring/res/values/strings.xml     |  4 ----
 7 files changed, 81 deletions(-)
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/BUILD
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml
 delete mode 100644 test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml

diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml b/test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml
deleted file mode 100644
index 67e5eae7..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/AndroidManifest.xml
+++ /dev/null
@@ -1,19 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.desugaring" >
-
-    <uses-sdk
-        android:minSdkVersion="28"
-        android:targetSdkVersion="34" />
-
-    <application>
-        <activity
-            android:name="com.desugaring.DesugaringActivity"
-            android:exported="true">
-            <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
-        </activity>
-    </application>
-</manifest>
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/BUILD b/test/rules/android_binary/r8_integration/java/com/desugaring/BUILD
deleted file mode 100644
index 33409397..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/BUILD
+++ /dev/null
@@ -1,16 +0,0 @@
-load("//rules:rules.bzl", "android_binary", "android_library")
-
-android_library(
-    name = "duration_lib",
-    srcs = ["DurationUser.java"],
-)
-
-android_binary(
-    name = "desugaring_app_r8",
-    srcs = ["DesugaringActivity.java"],
-    manifest = "AndroidManifest.xml",
-    proguard_specs = ["proguard.cfg"],
-    resource_files = glob(["res/**"]),
-    visibility = ["//test/rules/android_binary/r8_integration:__pkg__"],
-    deps = [":duration_lib"],
-)
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java b/test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java
deleted file mode 100644
index d9c42a68..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/DesugaringActivity.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package com.desugaring;
-
-import android.app.Activity;
-import android.os.Bundle;
-import java.time.Duration;
-
-/** Activity that exercises Duration.toSeconds() to test core library desugaring. */
-public class DesugaringActivity extends Activity {
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-        // Force the compiler to retain the call to DurationUser.getSeconds
-        long seconds = DurationUser.getSeconds(Duration.ofMinutes(5));
-        setTitle("Seconds: " + seconds);
-    }
-}
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java b/test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java
deleted file mode 100644
index 2c63bec7..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/DurationUser.java
+++ /dev/null
@@ -1,18 +0,0 @@
-package com.desugaring;
-
-import java.time.Duration;
-
-/**
- * A class that uses Duration.toSeconds(), which was added in API 31.
- * This simulates a third-party library (like Google Nav SDK) that calls
- * methods not available on all supported API levels.
- *
- * Without core library desugaring, this causes NoSuchMethodError on
- * API 26-30 devices.
- */
-public class DurationUser {
-    public static long getSeconds(Duration duration) {
-        // Duration.toSeconds() requires API 31+
-        return duration.toSeconds();
-    }
-}
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg b/test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg
deleted file mode 100644
index 7ef29b7a..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/proguard.cfg
+++ /dev/null
@@ -1,2 +0,0 @@
--dontobfuscate
--keep class com.desugaring.DurationUser { *; }
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml b/test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml
deleted file mode 100644
index bce65f74..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/res/layout/activity_main.xml
+++ /dev/null
@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent">
-</LinearLayout>
diff --git a/test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml b/test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml
deleted file mode 100644
index a5efdad9..00000000
--- a/test/rules/android_binary/r8_integration/java/com/desugaring/res/values/strings.xml
+++ /dev/null
@@ -1,4 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<resources>
-    <string name="app_name">Desugaring Test</string>
-</resources>

From c12dfa35f12d5af195f871c75627fcf6d879e537 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 12:48:32 -0700
Subject: [PATCH 11/13] Maybe more

---
 .../javatests/com/google/devtools/build/android/dexer/BUILD | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD b/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
index 16e5a699..79d2acfb 100644
--- a/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
+++ b/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
@@ -58,9 +58,9 @@ java_test(
         ":simple_jar",
     ],
     jvm_flags = [
-        "-Djsimplejar=google3/$(location :jsimple_jar)",
-        "-Dmultidexjar=google3/$(location :multidex_jar)",
-        "-Dsimplejar=google3/$(location :simple_jar)",
+        "-Djsimplejar=_main/$(location :jsimple_jar)",
+        "-Dmultidexjar=_main/$(location :multidex_jar)",
+        "-Dsimplejar=_main/$(location :simple_jar)",
     ],
     runtime_deps = [
         ":tests",

From c53da039421d5fca81dd4d622e00242eea04b275 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 13:03:53 -0700
Subject: [PATCH 12/13] Maybe more

---
 .../javatests/com/google/devtools/build/android/dexer/BUILD | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD b/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
index 79d2acfb..644bf548 100644
--- a/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
+++ b/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
@@ -58,9 +58,9 @@ java_test(
         ":simple_jar",
     ],
     jvm_flags = [
-        "-Djsimplejar=_main/$(location :jsimple_jar)",
-        "-Dmultidexjar=_main/$(location :multidex_jar)",
-        "-Dsimplejar=_main/$(location :simple_jar)",
+        "-Djsimplejar=$(rlocationpath :jsimple_jar)",
+        "-Dmultidexjar=$(rlocationpath :multidex_jar)",
+        "-Dsimplejar=$(rlocationpath :simple_jar)",
     ],
     runtime_deps = [
         ":tests",

From 6270b93245f11b448bb3c291e9958edbb9fe3e64 Mon Sep 17 00:00:00 2001
From: Ben Lee <ben@ben.cm>
Date: Fri, 20 Mar 2026 15:10:25 -0700
Subject: [PATCH 13/13] Revert

---
 .../javatests/com/google/devtools/build/android/dexer/BUILD | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD b/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
index 644bf548..16e5a699 100644
--- a/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
+++ b/src/tools/javatests/com/google/devtools/build/android/dexer/BUILD
@@ -58,9 +58,9 @@ java_test(
         ":simple_jar",
     ],
     jvm_flags = [
-        "-Djsimplejar=$(rlocationpath :jsimple_jar)",
-        "-Dmultidexjar=$(rlocationpath :multidex_jar)",
-        "-Dsimplejar=$(rlocationpath :simple_jar)",
+        "-Djsimplejar=google3/$(location :jsimple_jar)",
+        "-Dmultidexjar=google3/$(location :multidex_jar)",
+        "-Dsimplejar=google3/$(location :simple_jar)",
     ],
     runtime_deps = [
         ":tests",