AAPT2: Workaround for feature splits without namespacing

Android Instant Apps in its current iteration does not use namespaces,
but due to limitations on the Android resource runtime, needs to make
it look like it does.

This is due to a bug that treats any package ID that's not 0x01 or 0x7F
as a shared library. Shared libraries require unique package names.

As a workaround, and since Android Instant Apps can not have a feature
depend on another feature, we can alter the resource package name of a
feature split just before writing it out to disk. This avoids using a
unique package name while linking, thereby avoiding namespace issues.

Bug: 68820737
Test: manual
Merged-In: Ic553ed42656436bbb949393d0248ee7bb9d37860
Change-Id: Ic553ed42656436bbb949393d0248ee7bb9d37860

diff --git a/tests/FeatureSplit/base/Android.mk b/tests/FeatureSplit/base/Android.mk
index 93f6d7a..6da1b38 100644 (file)
--- a/tests/FeatureSplit/base/Android.mk
+++ b/tests/FeatureSplit/base/Android.mk
@@ -17,6 +17,7 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
+LOCAL_USE_AAPT2 := true
 LOCAL_SRC_FILES := $(call all-subdir-java-files)
 LOCAL_PACKAGE_NAME := FeatureSplitBase
 LOCAL_EXPORT_PACKAGE_RESOURCES := true

diff --git a/tests/FeatureSplit/feature1/res/values/values.xml b/tests/FeatureSplit/feature1/res/values/values.xml
index 10dbd97..7d58865 100644 (file)
--- a/tests/FeatureSplit/feature1/res/values/values.xml
+++ b/tests/FeatureSplit/feature1/res/values/values.xml
@@ -20,7 +20,7 @@
     <integer name="test_integer2">200</integer>
     <color name="test_color2">#00ff00</color>
     <string-array name="string_array2">
-        <item>@*string/app_title</item>
+        <item>@string/app_title</item>
     </string-array>
 </resources>
 

diff --git a/tools/aapt2/ResourceValues.cpp b/tools/aapt2/ResourceValues.cpp
index a5ddc52..0fe1a1f 100644 (file)
--- a/tools/aapt2/ResourceValues.cpp
+++ b/tools/aapt2/ResourceValues.cpp
@@ -95,7 +95,7 @@ bool Reference::Equals(const Value* value) const {
 bool Reference::Flatten(android::Res_value* out_value) const {
   const ResourceId resid = id.value_or_default(ResourceId(0));
   const bool dynamic = resid.is_valid_dynamic() && resid.package_id() != kFrameworkPackageId &&
-                       resid.package_id() != kAppPackageId;
+                       resid.package_id() < kAppPackageId;
 
   if (reference_type == Reference::Type::kResource) {
     if (dynamic) {

diff --git a/tools/aapt2/cmd/Link.cpp b/tools/aapt2/cmd/Link.cpp
index fea11ed..5fc35b8 100644 (file)
--- a/tools/aapt2/cmd/Link.cpp
+++ b/tools/aapt2/cmd/Link.cpp
@@ -754,6 +754,9 @@ class LinkCommand {
     for (auto& entry : asset_source->GetAssignedPackageIds()) {
       if (entry.first > kFrameworkPackageId && entry.first < kAppPackageId) {
         final_table_.included_packages_[entry.first] = entry.second;
+      } else if (entry.first == kAppPackageId) {
+        // Capture the included base feature package.
+        included_feature_base_ = entry.second;
       }
     }
 
@@ -1408,17 +1411,53 @@ class LinkCommand {
       return false;
     }
 
-    if (context_->GetPackageType() == PackageType::kStaticLib) {
-      if (!FlattenTableToPb(table, writer)) {
-        return false;
+    // Hack to fix b/68820737.
+    // We need to modify the ResourceTable's package name, but that should NOT affect
+    // anything else being generated, which includes the Java classes.
+    // If required, the package name is modifed before flattening, and then modified back
+    // to its original name.
+    ResourceTablePackage* package_to_rewrite = nullptr;
+    if (context_->GetPackageId() > kAppPackageId &&
+        included_feature_base_ == make_value(context_->GetCompilationPackage())) {
+      // The base APK is included, and this is a feature split. If the base package is
+      // the same as this package, then we are building an old style Android Instant Apps feature
+      // split and must apply this workaround to avoid requiring namespaces support.
+      package_to_rewrite = table->FindPackage(context_->GetCompilationPackage());
+      if (package_to_rewrite != nullptr) {
+        CHECK_EQ(1u, table->packages.size()) << "can't change name of package when > 1 package";
+
+        std::string new_package_name =
+            StringPrintf("%s.%s", package_to_rewrite->name.c_str(),
+                         app_info_.split_name.value_or_default("feature").c_str());
+
+        if (context_->IsVerbose()) {
+          context_->GetDiagnostics()->Note(
+              DiagMessage() << "rewriting resource package name for feature split to '"
+                            << new_package_name << "'");
+        }
+        package_to_rewrite->name = new_package_name;
       }
+    }
+
+    bool success;
+    if (context_->GetPackageType() == PackageType::kStaticLib) {
+      success = FlattenTableToPb(table, writer);
     } else {
-      if (!FlattenTable(table, writer)) {
-        context_->GetDiagnostics()->Error(DiagMessage() << "failed to write resources.arsc");
-        return false;
+      success = FlattenTable(table, writer);
+    }
+
+    if (package_to_rewrite != nullptr) {
+      // Change the name back.
+      package_to_rewrite->name = context_->GetCompilationPackage();
+      if (package_to_rewrite->id) {
+        table->included_packages_.erase(package_to_rewrite->id.value());
       }
     }
-    return true;
+
+    if (!success) {
+      context_->GetDiagnostics()->Error(DiagMessage() << "failed to write resource table");
+    }
+    return success;
   }
 
   int Run(const std::vector<std::string>& input_files) {
@@ -1447,8 +1486,8 @@ class LinkCommand {
       return 1;
     }
 
-    const AppInfo& app_info = maybe_app_info.value();
-    context_->SetMinSdkVersion(app_info.min_sdk_version.value_or_default(0));
+    app_info_ = maybe_app_info.value();
+    context_->SetMinSdkVersion(app_info_.min_sdk_version.value_or_default(0));
 
     context_->SetNameManglerPolicy(NameManglerPolicy{context_->GetCompilationPackage()});
 
@@ -1647,7 +1686,7 @@ class LinkCommand {
 
         // Generate an AndroidManifest.xml for each split.
         std::unique_ptr<xml::XmlResource> split_manifest =
-            GenerateSplitManifest(app_info, *split_constraints_iter);
+            GenerateSplitManifest(app_info_, *split_constraints_iter);
 
         XmlReferenceLinker linker;
         if (!linker.Consume(context_, split_manifest.get())) {
@@ -1815,6 +1854,8 @@ class LinkCommand {
   LinkContext* context_;
   ResourceTable final_table_;
 
+  AppInfo app_info_;
+
   std::unique_ptr<TableMerger> table_merger_;
 
   // A pointer to the FileCollection representing the filesystem (not archives).
@@ -1830,6 +1871,9 @@ class LinkCommand {
 
   // The set of shared libraries being used, mapping their assigned package ID to package name.
   std::map<size_t, std::string> shared_libs_;
+
+  // The package name of the base application, if it is included.
+  Maybe<std::string> included_feature_base_;
 };
 
 int Link(const std::vector<StringPiece>& args, IDiagnostics* diagnostics) {

diff --git a/tools/aapt2/flatten/TableFlattener.cpp b/tools/aapt2/flatten/TableFlattener.cpp
index 14b776b..3292421 100644 (file)
--- a/tools/aapt2/flatten/TableFlattener.cpp
+++ b/tools/aapt2/flatten/TableFlattener.cpp
@@ -23,6 +23,7 @@
 
 #include "android-base/logging.h"
 #include "android-base/macros.h"
+#include "android-base/stringprintf.h"
 
 #include "ResourceTable.h"
 #include "ResourceValues.h"
@@ -572,14 +573,6 @@ bool TableFlattener::Consume(IAaptContext* context, ResourceTable* table) {
   ResTable_header* table_header = table_writer.StartChunk<ResTable_header>(RES_TABLE_TYPE);
   table_header->packageCount = util::HostToDevice32(table->packages.size());
 
-  // Write a self mapping entry for this package if the ID is non-standard (0x7f).
-  if (context->GetPackageType() == PackageType::kApp) {
-    const uint8_t package_id = context->GetPackageId();
-    if (package_id != kFrameworkPackageId && package_id != kAppPackageId) {
-      table->included_packages_[package_id] = context->GetCompilationPackage();
-    }
-  }
-
   // Flatten the values string pool.
   StringPool::FlattenUtf8(table_writer.buffer(), table->string_pool);
 
@@ -587,6 +580,22 @@ bool TableFlattener::Consume(IAaptContext* context, ResourceTable* table) {
 
   // Flatten each package.
   for (auto& package : table->packages) {
+    if (context->GetPackageType() == PackageType::kApp) {
+      // Write a self mapping entry for this package if the ID is non-standard (0x7f).
+      const uint8_t package_id = package->id.value();
+      if (package_id != kFrameworkPackageId && package_id != kAppPackageId) {
+        auto result = table->included_packages_.insert({package_id, package->name});
+        if (!result.second && result.first->second != package->name) {
+          // A mapping for this package ID already exists, and is a different package. Error!
+          context->GetDiagnostics()->Error(
+              DiagMessage() << android::base::StringPrintf(
+                  "can't map package ID %02x to '%s'. Already mapped to '%s'", package_id,
+                  package->name.c_str(), result.first->second.c_str()));
+          return false;
+        }
+      }
+    }
+
     PackageFlattener flattener(context, package.get(), &table->included_packages_,
                                options_.use_sparse_entries);
     if (!flattener.FlattenPackage(&package_buffer)) {