1 files changed, 49 insertions, 12 deletions

diff --git a/tools/aapt2/link/TableMerger.cpp b/tools/aapt2/link/TableMerger.cpp
index e819f51a5634..d777e22fa4b7 100644
--- a/tools/aapt2/link/TableMerger.cpp
+++ b/tools/aapt2/link/TableMerger.cpp
@@ -101,8 +101,18 @@ static bool MergeType(IAaptContext* context, const Source& src, ResourceTableTyp
   return true;
 }
 
-static bool MergeEntry(IAaptContext* context, const Source& src, bool overlay,
-                       ResourceEntry* dst_entry, ResourceEntry* src_entry) {
+static bool MergeEntry(IAaptContext* context, const Source& src,
+                       ResourceEntry* dst_entry, ResourceEntry* src_entry,
+                       bool strict_visibility) {
+  if (strict_visibility
+      && dst_entry->visibility.level != Visibility::Level::kUndefined
+      && src_entry->visibility.level != dst_entry->visibility.level) {
+      context->GetDiagnostics()->Error(
+          DiagMessage(src) << "cannot merge resource '" << dst_entry->name << "' with conflicting visibilities: "
+                           << "public and private");
+    return false;
+  }
+
   // Copy over the strongest visibility.
   if (src_entry->visibility.level > dst_entry->visibility.level) {
     // Only copy the ID if the source is public, or else the ID is meaningless.
@@ -124,17 +134,35 @@ static bool MergeEntry(IAaptContext* context, const Source& src, bool overlay,
     dst_entry->allow_new = std::move(src_entry->allow_new);
   }
 
-  if (src_entry->overlayable) {
-    if (dst_entry->overlayable && !overlay) {
-      context->GetDiagnostics()->Error(DiagMessage(src_entry->overlayable.value().source)
-                                       << "duplicate overlayable declaration for resource '"
-                                       << src_entry->name << "'");
-      context->GetDiagnostics()->Error(DiagMessage(dst_entry->overlayable.value().source)
-                                       << "previous declaration here");
-      return false;
+  for (auto& src_overlayable : src_entry->overlayable_declarations) {
+    for (auto& dst_overlayable : dst_entry->overlayable_declarations) {
+      // An overlayable resource cannot be declared twice with the same policy
+      if (src_overlayable.policy == dst_overlayable.policy) {
+        context->GetDiagnostics()->Error(DiagMessage(src_overlayable.source)
+                                             << "duplicate overlayable declaration for resource '"
+                                             << src_entry->name << "'");
+        context->GetDiagnostics()->Error(DiagMessage(dst_overlayable.source)
+                                             << "previous declaration here");
+        return false;
+      }
+
+      // An overlayable resource cannot be declared once with a policy and without a policy because
+      // the policy becomes unused
+      if (!src_overlayable.policy || !dst_overlayable.policy) {
+        context->GetDiagnostics()->Error(DiagMessage(src_overlayable.source)
+                                             << "overlayable resource '" << src_entry->name
+                                             << "' declared once with a policy and once with no "
+                                             << "policy");
+        context->GetDiagnostics()->Error(DiagMessage(dst_overlayable.source)
+                                             << "previous declaration here");
+        return false;
+      }
     }
-    dst_entry->overlayable = std::move(src_entry->overlayable);
   }
+
+  dst_entry->overlayable_declarations.insert(dst_entry->overlayable_declarations.end(),
+                                             src_entry->overlayable_declarations.begin(),
+                                             src_entry->overlayable_declarations.end());
   return true;
 }
 
@@ -234,7 +262,7 @@ bool TableMerger::DoMerge(const Source& src, ResourceTable* src_table,
         continue;
       }
 
-      if (!MergeEntry(context_, src, overlay, dst_entry, src_entry.get())) {
+      if (!MergeEntry(context_, src, dst_entry, src_entry.get(), options_.strict_visibility)) {
         error = true;
         continue;
       }
@@ -271,8 +299,17 @@ bool TableMerger::DoMerge(const Source& src, ResourceTable* src_table,
           dst_config_value->value = std::move(new_file_ref);
 
         } else {
+          Maybe<std::string> original_comment = (dst_config_value->value)
+              ? dst_config_value->value->GetComment() : Maybe<std::string>();
+
           dst_config_value->value = std::unique_ptr<Value>(
               src_config_value->value->Clone(&master_table_->string_pool));
+
+          // Keep the comment from the original resource and ignore all comments from overlaying
+          // resources
+          if (overlay && original_comment) {
+            dst_config_value->value->SetComment(original_comment.value());
+          }
         }
       }
     }