Fix repeated field merging semantics.

The public doc states that repeated fields are simply concatenated
and doesn't impose a different semantics for packed fields. This
CL fixes this for packed fields and adds tests covering all cases.

Also fixed a bit of missed null-repeated-field treatments.

Change-Id: Ie35277bb1a9f0b8171dc9d07b6adf9b9d3308de2

1 files changed, 12 insertions, 10 deletions

diff --git a/src/google/protobuf/compiler/javanano/javanano_message_field.cc b/src/google/protobuf/compiler/javanano/javanano_message_field.cc
index 04f1c14..027428f 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_message_field.cc
@@ -235,34 +235,36 @@ GenerateMergingCode(io::Printer* printer) const {
     "    .getRepeatedFieldArrayLength(input, $tag$);\n"
     "int i = this.$name$ == null ? 0 : this.$name$.length;\n"
     "$type$[] newArray = new $type$[i + arrayLength];\n"
-    "if (this.$name$ != null) {\n"
-    "  System.arraycopy(this.$name$, 0, newArray, 0, i);\n"
+    "if (i != 0) {\n"
+    "  java.lang.System.arraycopy(this.$name$, 0, newArray, 0, i);\n"
     "}\n"
-    "this.$name$ = newArray;\n"
-    "for (; i < this.$name$.length - 1; i++) {\n"
-    "  this.$name$[i] = new $type$();\n");
+    "for (; i < newArray.length - 1; i++) {\n"
+    "  newArray[i] = new $type$();\n");
 
   if (descriptor_->type() == FieldDescriptor::TYPE_GROUP) {
     printer->Print(variables_,
-      "  input.readGroup(this.$name$[i], $number$);\n");
+      "  input.readGroup(newArray[i], $number$);\n");
   } else {
     printer->Print(variables_,
-      "  input.readMessage(this.$name$[i]);\n");
+      "  input.readMessage(newArray[i]);\n");
   }
 
   printer->Print(variables_,
     "  input.readTag();\n"
     "}\n"
     "// Last one without readTag.\n"
-    "this.$name$[i] = new $type$();\n");
+    "newArray[i] = new $type$();\n");
 
   if (descriptor_->type() == FieldDescriptor::TYPE_GROUP) {
     printer->Print(variables_,
-      "input.readGroup(this.$name$[i], $number$);\n");
+      "input.readGroup(newArray[i], $number$);\n");
   } else {
     printer->Print(variables_,
-      "input.readMessage(this.$name$[i]);\n");
+      "input.readMessage(newArray[i]);\n");
   }
+
+  printer->Print(variables_,
+    "this.$name$ = newArray;\n");
 }
 
 void RepeatedMessageFieldGenerator::