Sync code with Google-internal branch. Changes:

Protoc (parser)
- Improved error message when an enum value's name conflicts with another
  symbol defined in the enum type's scope, e.g. if two enum types declared
  in the same scope have values with the same name.  This is disallowed for
  compatibility with C++, but this wasn't clear from the error.
C++
- Restored the set_foo(const char*) accessor for "bytes" type because some
  code inside Google depends on it.  However, set_foo(const char*, int) is
  still there (and actually is changed to take const void*).
- Fixed TokenizerTest when compiling with -DNDEBUG on Linux.
- Other irrelevant tweaks.
Java
- Fixed UnknownFieldSet's parsing of varints larger than 32 bits.
- Fixed TextFormat's parsing of "inf" and "nan".
- Fixed TextFormat's parsing of comments.
Python
- Fixed text_format_test on Windows where floating-point exponents sometimes
  contain extra zeros.

1 files changed, 39 insertions, 7 deletions

diff --git a/src/google/protobuf/descriptor.cc b/src/google/protobuf/descriptor.cc
index c75cf623..48db0cc2 100644
--- a/src/google/protobuf/descriptor.cc
+++ b/src/google/protobuf/descriptor.cc
@@ -1604,8 +1604,10 @@ class DescriptorBuilder {
   // FindSymbol("foo.bar").
   Symbol LookupSymbol(const string& name, const string& relative_to);
 
-  // Calls tables_->AddSymbol() and records an error if it fails.
-  void AddSymbol(const string& full_name,
+  // Calls tables_->AddSymbol() and records an error if it fails.  Returns
+  // true if successful or false if failed, though most callers can ignore
+  // the return value since an error has already been recorded.
+  bool AddSymbol(const string& full_name,
                  const void* parent, const string& name,
                  const Message& proto, Symbol symbol);
 
@@ -1918,14 +1920,16 @@ Symbol DescriptorBuilder::LookupSymbol(
   }
 }
 
-void DescriptorBuilder::AddSymbol(
+bool DescriptorBuilder::AddSymbol(
     const string& full_name, const void* parent, const string& name,
     const Message& proto, Symbol symbol) {
   // If the caller passed NULL for the parent, the symbol is at file scope.
   // Use its file as the parent instead.
   if (parent == NULL) parent = file_;
 
-  if (!tables_->AddSymbol(full_name, parent, name, symbol)) {
+  if (tables_->AddSymbol(full_name, parent, name, symbol)) {
+    return true;
+  } else {
     const FileDescriptor* other_file = tables_->FindSymbol(full_name).GetFile();
     if (other_file == file_) {
       string::size_type dot_pos = full_name.find_last_of('.');
@@ -1944,6 +1948,7 @@ void DescriptorBuilder::AddSymbol(
                "\"" + full_name + "\" is already defined in file \"" +
                other_file->name() + "\".");
     }
+    return false;
   }
 }
 
@@ -2480,14 +2485,41 @@ void DescriptorBuilder::BuildEnumValue(const EnumValueDescriptorProto& proto,
   // Again, enum values are weird because we makes them appear as siblings
   // of the enum type instead of children of it.  So, we use
   // parent->containing_type() as the value's parent.
-  AddSymbol(result->full_name(), parent->containing_type(), result->name(),
-            proto, Symbol(result));
+  bool added_to_outer_scope =
+    AddSymbol(result->full_name(), parent->containing_type(), result->name(),
+              proto, Symbol(result));
 
   // However, we also want to be able to search for values within a single
   // enum type, so we add it as a child of the enum type itself, too.
   // Note:  This could fail, but if it does, the error has already been
   //   reported by the above AddSymbol() call, so we ignore the return code.
-  tables_->AddAliasUnderParent(parent, result->name(), Symbol(result));
+  bool added_to_inner_scope =
+    tables_->AddAliasUnderParent(parent, result->name(), Symbol(result));
+
+  if (added_to_inner_scope && !added_to_outer_scope) {
+    // This value did not conflict with any values defined in the same enum,
+    // but it did conflict with some other symbol defined in the enum type's
+    // scope.  Let's print an additional error to explain this.
+    string outer_scope;
+    if (parent->containing_type() == NULL) {
+      outer_scope = file_->package();
+    } else {
+      outer_scope = parent->containing_type()->full_name();
+    }
+
+    if (outer_scope.empty()) {
+      outer_scope = "the global scope";
+    } else {
+      outer_scope = "\"" + outer_scope + "\"";
+    }
+
+    AddError(result->full_name(), proto,
+             DescriptorPool::ErrorCollector::NAME,
+             "Note that enum values use C++ scoping rules, meaning that "
+             "enum values are siblings of their type, not children of it.  "
+             "Therefore, \"" + result->name() + "\" must be unique within "
+             + outer_scope + ", not just within \"" + parent->name() + "\".");
+  }
 
   // An enum is allowed to define two numbers that refer to the same value.
   // FindValueByNumber() should return the first such value, so we simply