Protect against null repeated fields.

There's no distinction between a repeated field being null and being
empty. In both cases, nothing is sent on the wire. Clients might for
whatever reason inadvertently set a repeated field to null, so
protect against that and treat it just as if the field was empty.

Change-Id: Ic3846f7f2189d6cfff6f8ef3ca217daecc3c8be7

3 files changed, 25 insertions, 18 deletions

diff --git a/src/google/protobuf/compiler/javanano/javanano_enum_field.cc b/src/google/protobuf/compiler/javanano/javanano_enum_field.cc
index 420d3c2..cdb3d09 100644
--- a/src/google/protobuf/compiler/javanano/javanano_enum_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_enum_field.cc
@@ -293,7 +293,7 @@ GenerateMergingCode(io::Printer* printer) const {
 void RepeatedEnumFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if (this.$name$.length > 0) {\n");
+    "if (this.$name$ != null && this.$name$.length > 0) {\n");
   printer->Indent();
 
   if (descriptor_->options().packed()) {
@@ -317,7 +317,7 @@ GenerateSerializationCode(io::Printer* printer) const {
 void RepeatedEnumFieldGenerator::
 GenerateSerializedSizeCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if (this.$name$.length > 0) {\n");
+    "if (this.$name$ != null && this.$name$.length > 0) {\n");
   printer->Indent();
 
   printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/javanano/javanano_message_field.cc b/src/google/protobuf/compiler/javanano/javanano_message_field.cc
index 277eb4e..04f1c14 100644
--- a/src/google/protobuf/compiler/javanano/javanano_message_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_message_field.cc
@@ -233,9 +233,11 @@ GenerateMergingCode(io::Printer* printer) const {
   printer->Print(variables_,
     "int arrayLength = com.google.protobuf.nano.WireFormatNano"
     "    .getRepeatedFieldArrayLength(input, $tag$);\n"
-    "int i = this.$name$.length;\n"
+    "int i = this.$name$ == null ? 0 : this.$name$.length;\n"
     "$type$[] newArray = new $type$[i + arrayLength];\n"
-    "System.arraycopy(this.$name$, 0, newArray, 0, i);\n"
+    "if (this.$name$ != null) {\n"
+    "  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");
@@ -266,17 +268,21 @@ GenerateMergingCode(io::Printer* printer) const {
 void RepeatedMessageFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "for ($type$ element : this.$name$) {\n"
-    "  output.write$group_or_message$($number$, element);\n"
+    "if (this.$name$ != null) {\n"
+    "  for ($type$ element : this.$name$) {\n"
+    "    output.write$group_or_message$($number$, element);\n"
+    "  }\n"
     "}\n");
 }
 
 void RepeatedMessageFieldGenerator::
 GenerateSerializedSizeCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "for ($type$ element : this.$name$) {\n"
-    "  size += com.google.protobuf.nano.CodedOutputByteBufferNano\n"
-    "    .compute$group_or_message$Size($number$, element);\n"
+    "if (this.$name$ != null) {\n"
+    "  for ($type$ element : this.$name$) {\n"
+    "    size += com.google.protobuf.nano.CodedOutputByteBufferNano\n"
+    "      .compute$group_or_message$Size($number$, element);\n"
+    "  }\n"
     "}\n");
 }
 
diff --git a/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc b/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc
index f5e27d6..8097be8 100644
--- a/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc
+++ b/src/google/protobuf/compiler/javanano/javanano_primitive_field.cc
@@ -570,17 +570,15 @@ GenerateRepeatedDataSizeCode(io::Printer* printer) const {
 
 void RepeatedPrimitiveFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "if (this.$name$ != null && this.$name$.length > 0) {\n");
+  printer->Indent();
+
   if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "if (this.$name$.length > 0) {\n");
-    printer->Indent();
     GenerateRepeatedDataSizeCode(printer);
-    printer->Outdent();
-    printer->Print(variables_,
-      "  output.writeRawVarint32($tag$);\n"
-      "  output.writeRawVarint32(dataSize);\n"
-      "}\n");
     printer->Print(variables_,
+      "output.writeRawVarint32($tag$);\n"
+      "output.writeRawVarint32(dataSize);\n"
       "for ($type$ element : this.$name$) {\n"
       "  output.write$capitalized_type$NoTag(element);\n"
       "}\n");
@@ -590,12 +588,15 @@ GenerateSerializationCode(io::Printer* printer) const {
       "  output.write$capitalized_type$($number$, element);\n"
       "}\n");
   }
+
+  printer->Outdent();
+  printer->Print("}\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::
 GenerateSerializedSizeCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if (this.$name$.length > 0) {\n");
+    "if (this.$name$ != null && this.$name$.length > 0) {\n");
   printer->Indent();
 
   GenerateRepeatedDataSizeCode(printer);