2014-08-15 version 2.6.0:

General

* Added oneofs(unions) feature. Fields in the same oneof will share

memory and at most one field can be set at the same time. Use the

oneof keyword to define a oneof like:

message SampleMessage {

oneof test_oneof {

string name = 4;

YourMessage sub_message = 9;

}

}

* Files, services, enums, messages, methods and enum values can be marked

as deprecated now.

* Added Support for list values, including lists of mesaages, when

parsing text-formatted protos in C++ and Java.

For example: foo: [1, 2, 3]

C++

* Enhanced customization on TestFormat printing.

* Added SwapFields() in reflection API to swap a subset of fields.

Added SetAllocatedMessage() in reflection API.

* Repeated primitive extensions are now packable. The

[packed=true] option only affects serializers. Therefore, it is

possible to switch a repeated extension field to packed format

without breaking backwards-compatibility.

* Various speed optimizations.

Java

* writeTo() method in ByteString can now write a substring to an

output stream. Added endWith() method for ByteString.

* ByteString and ByteBuffer are now supported in CodedInputStream

and CodedOutputStream.

* java_generate_equals_and_hash can now be used with the LITE_RUNTIME.

Python

* A new C++-backed extension module (aka "cpp api v2") that replaces the

old ("cpp api v1") one. Much faster than the pure Python code. This one

resolves many bugs and is recommended for general use over the

pure Python when possible.

* Descriptors now have enum_types_by_name and extension_types_by_name dict

attributes.

* Support for Python 3.

2013-02-27 version 2.5.0:

General

* New notion "import public" that allows a proto file to forward the content

it imports to its importers. For example,

// foo.proto

import public "bar.proto";

import "baz.proto";

// qux.proto

import "foo.proto";

// Stuff defined in bar.proto may be used in this file, but stuff from

// baz.proto may NOT be used without importing it explicitly.

This is useful for moving proto files. To move a proto file, just leave

a single "import public" in the old proto file.

* New enum option "allow_alias" that specifies whether different symbols can

be assigned the same numeric value. Default value is "true". Setting it to

false causes the compiler to reject enum definitions where multiple symbols

have the same numeric value.

Note: We plan to flip the default value to "false" in a future release.

Projects using enum aliases should set the option to "true" in their .proto

files.

C++

* New generated method set_allocated_foo(Type* foo) for message and string

fields. This method allows you to set the field to a pre-allocated object

and the containing message takes the ownership of that object.

* Added SetAllocatedExtension() and ReleaseExtension() to extensions API.

* Custom options are now formatted correctly when descriptors are printed in

text format.

* Various speed optimizations.

Java

* Comments in proto files are now collected and put into generated code as

comments for corresponding classes and data members.

* Added Parser to parse directly into messages without a Builder. For

example,

Foo foo = Foo.PARSER.ParseFrom(input);

Using Parser is ~25% faster than using Builder to parse messages.

* Added getters/setters to access the underlying ByteString of a string field

directly.

* ByteString now supports more operations: substring(), prepend(), and

append(). The implementation of ByteString uses a binary tree structure

to support these operations efficiently.

* New method findInitializationErrors() that lists all missing required

fields.

* Various code size and speed optimizations.

Python

* Added support for dynamic message creation. DescriptorDatabase,

DescriptorPool, and MessageFactory work like their C++ couterparts to

simplify Descriptor construction from *DescriptorProtos, and MessageFactory

provides a message instance from a Descriptor.

* Added pickle support for protobuf messages.

* Unknown fields are now preserved after parsing.

* Fixed bug where custom options were not correctly populated. Custom

options can be accessed now.

* Added EnumTypeWrapper that provides better accessibility to enum types.

* Added ParseMessage(descriptor, bytes) to generate a new Message instance

from a descriptor and a byte string.

2011-05-01 version 2.4.1:

C++

* Fixed the frendship problem for old compilers to make the library now gcc 3

compatible again.

* Fixed vcprojects/extract_includes.bat to extract compiler/plugin.h.

Java

* Removed usages of JDK 1.6 only features to make the library now JDK 1.5

compatible again.

* Fixed a bug about negative enum values.

* serialVersionUID is now defined in generated messages for java serializing.

* Fixed protoc to use java.lang.Object, which makes "Object" now a valid

message name again.

Python

* Experimental C++ implementation now requires C++ protobuf library installed.

See the README.txt in the python directory for details.

2011-02-02 version 2.4.0:

General

* The RPC (cc|java|py)_generic_services default value is now false instead of

true.

* Custom options can have aggregate types. For example,

message MyOption {

optional string comment = 1;

optional string author = 2;

}

extend google.protobuf.FieldOptions {

optional MyOption myoption = 12345;

}

This option can now be set as follows:

message SomeType {

optional int32 field = 1 [(myoption) = { comment:'x' author:'y' }];

}

C++

* Various speed and code size optimizations.

* Added a release_foo() method on string and message fields.

* Fixed gzip_output_stream sub-stream handling.

Java

* Builders now maintain sub-builders for sub-messages. Use getFooBuilder() to

get the builder for the sub-message "foo". This allows you to repeatedly

modify deeply-nested sub-messages without rebuilding them.

* Builder.build() no longer invalidates the Builder for generated messages

(You may continue to modify it and then build another message).

* Code generator will generate efficient equals() and hashCode()

implementations if new option java_generate_equals_and_hash is enabled.

(Otherwise, reflection-based implementations are used.)

* Generated messages now implement Serializable.

* Fields with [deprecated=true] will be marked with @Deprecated in Java.

* Added lazy conversion of UTF-8 encoded strings to String objects to improve

performance.

* Various optimizations.

* Enum value can be accessed directly, instead of calling getNumber() on the

enum member.

* For each enum value, an integer constant is also generated with the suffix

_VALUE.

Python

* Added an experimental C++ implementation for Python messages via a Python

extension. Implementation type is controlled by an environment variable

PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION (valid values: "cpp" and "python")

The default value is currently "python" but will be changed to "cpp" in

future release.

* Improved performance on message instantiation significantly.

Most of the work on message instantiation is done just once per message

class, instead of once per message instance.

* Improved performance on text message parsing.

* Allow add() to forward keyword arguments to the concrete class.

E.g. instead of

item = repeated_field.add()

item.foo = bar

item.baz = quux

You can do:

repeated_field.add(foo=bar, baz=quux)

* Added a sort() interface to the BaseContainer.

* Added an extend() method to repeated composite fields.

* Added UTF8 debug string support.

2010-01-08 version 2.3.0:

General

* Parsers for repeated numeric fields now always accept both packed and

unpacked input. The [packed=true] option only affects serializers.

Therefore, it is possible to switch a field to packed format without

breaking backwards-compatibility -- as long as all parties are using

protobuf 2.3.0 or above, at least.

* The generic RPC service code generated by the C++, Java, and Python

generators can be disabled via file options:

option cc_generic_services = false;

option java_generic_services = false;

option py_generic_services = false;

This allows plugins to generate alternative code, possibly specific to some

particular RPC implementation.

protoc

* Now supports a plugin system for code generators. Plugins can generate

code for new languages or inject additional code into the output of other

code generators. Plugins are just binaries which accept a protocol buffer

on stdin and write a protocol buffer to stdout, so they may be written in

any language. See src/google/protobuf/compiler/plugin.proto.

**WARNING**: Plugins are experimental. The interface may change in a

future version.

* If the output location ends in .zip or .jar, protoc will write its output

to a zip/jar archive instead of a directory. For example:

protoc --java_out=myproto_srcs.jar --python_out=myproto.zip myproto.proto

Currently the archive contents are not compressed, though this could change

in the future.

* inf, -inf, and nan can now be used as default values for float and double

fields.

C++

* Various speed and code size optimizations.

* DynamicMessageFactory is now fully thread-safe.

* Message::Utf8DebugString() method is like DebugString() but avoids escaping

UTF-8 bytes.

* Compiled-in message types can now contain dynamic extensions, through use

of CodedInputStream::SetExtensionRegistry().

* Now compiles shared libraries (DLLs) by default on Cygwin and MinGW, to

match other platforms. Use --disable-shared to avoid this.

Java

* parseDelimitedFrom() and mergeDelimitedFrom() now detect EOF and return

false/null instead of throwing an exception.

* Fixed some initialization ordering bugs.

* Fixes for OpenJDK 7.

Python

* 10-25 times faster than 2.2.0, still pure-Python.

* Calling a mutating method on a sub-message always instantiates the message

in its parent even if the mutating method doesn't actually mutate anything

(e.g. parsing from an empty string).

* Expanded descriptors a bit.

2009-08-11 version 2.2.0:

C++

* Lite mode: The "optimize_for = LITE_RUNTIME" option causes the compiler

to generate code which only depends libprotobuf-lite, which is much smaller

than libprotobuf but lacks descriptors, reflection, and some other features.

* Fixed bug where Message.Swap(Message) was only implemented for

optimize_for_speed. Swap now properly implemented in both modes

(Issue 91).

* Added RemoveLast and SwapElements(index1, index2) to Reflection

interface for repeated elements.

* Added Swap(Message) to Reflection interface.

* Floating-point literals in generated code that are intended to be

single-precision now explicitly have 'f' suffix to avoid pedantic warnings

produced by some compilers.

* The [deprecated=true] option now causes the C++ code generator to generate

a GCC-style deprecation annotation (no-op on other compilers).

* google::protobuf::GetEnumDescriptor<SomeGeneratedEnumType>() returns the

EnumDescriptor for that type -- useful for templates which cannot call

SomeGeneratedEnumType_descriptor().

* Various optimizations and obscure bug fixes.

Java

* Lite mode: The "optimize_for = LITE_RUNTIME" option causes the compiler

to generate code which only depends libprotobuf-lite, which is much smaller

than libprotobuf but lacks descriptors, reflection, and some other features.

* Lots of style cleanups.

Python

* Fixed endianness bug with floats and doubles.

* Text format parsing support.

* Fix bug with parsing packed repeated fields in embedded messages.

* Ability to initialize fields by passing keyword args to constructor.

* Support iterators in extend and __setslice__ for containers.

2009-05-13 version 2.1.0:

General

* Repeated fields of primitive types (types other that string, group, and

nested messages) may now use the option [packed = true] to get a more

efficient encoding. In the new encoding, the entire list is written

as a single byte blob using the "length-delimited" wire type. Within

this blob, the individual values are encoded the same way they would

be normally except without a tag before each value (thus, they are

tightly "packed").

* For each field, the generated code contains an integer constant assigned

to the field number. For example, the .proto file:

message Foo { optional int bar_baz = 123; }

would generate the following constants, all with the integer value 123:

C++: Foo::kBarBazFieldNumber

Java: Foo.BAR_BAZ_FIELD_NUMBER

Python: Foo.BAR_BAZ_FIELD_NUMBER

Constants are also generated for extensions, with the same naming scheme.

These constants may be used as switch cases.

* Updated bundled Google Test to version 1.3.0. Google Test is now bundled

in its verbatim form as a nested autoconf package, so you can drop in any

other version of Google Test if needed.

* optimize_for = SPEED is now the default, by popular demand. Use

optimize_for = CODE_SIZE if code size is more important in your app.

* It is now an error to define a default value for a repeated field.

Previously, this was silently ignored (it had no effect on the generated

code).

* Fields can now be marked deprecated like:

optional int32 foo = 1 [deprecated = true];

Currently this does not have any actual effect, but in the future the code

generators may generate deprecation annotations in each language.

* Cross-compiling should now be possible using the --with-protoc option to

configure. See README.txt for more info.

protoc

* --error_format=msvs option causes errors to be printed in Visual Studio

format, which should allow them to be clicked on in the build log to go

directly to the error location.

* The type name resolver will no longer resolve type names to fields. For

example, this now works:

message Foo {}

message Bar {

optional int32 Foo = 1;

optional Foo baz = 2;

}

Previously, the type of "baz" would resolve to "Bar.Foo", and you'd get

an error because Bar.Foo is a field, not a type. Now the type of "baz"

resolves to the message type Foo. This change is unlikely to make a

difference to anyone who follows the Protocol Buffers style guide.

C++

* Several optimizations, including but not limited to:

- Serialization, especially to flat arrays, is 10%-50% faster, possibly

more for small objects.

- Several descriptor operations which previously required locking no longer

do.

- Descriptors are now constructed lazily on first use, rather than at

process startup time. This should save memory in programs which do not

use descriptors or reflection.

- UnknownFieldSet completely redesigned to be more efficient (especially in

terms of memory usage).

- Various optimizations to reduce code size (though the serialization speed

optimizations increased code size).

* Message interface has method ParseFromBoundedZeroCopyStream() which parses

a limited number of bytes from an input stream rather than parsing until

EOF.

* GzipInputStream and GzipOutputStream support reading/writing gzip- or

zlib-compressed streams if zlib is available.

(google/protobuf/io/gzip_stream.h)

* DescriptorPool::FindAllExtensions() and corresponding

DescriptorDatabase::FindAllExtensions() can be used to enumerate all

extensions of a given type.

* For each enum type Foo, protoc will generate functions:

const string& Foo_Name(Foo value);

bool Foo_Parse(const string& name, Foo* result);

The former returns the name of the enum constant corresponding to the given

value while the latter finds the value corresponding to a name.

* RepeatedField and RepeatedPtrField now have back-insertion iterators.

* String fields now have setters that take a char* and a size, in addition

to the existing ones that took char* or const string&.

* DescriptorPool::AllowUnknownDependencies() may be used to tell

DescriptorPool to create placeholder descriptors for unknown entities

referenced in a FileDescriptorProto. This can allow you to parse a .proto

file without having access to other .proto files that it imports, for

example.

* Updated gtest to latest version. The gtest package is now included as a

nested autoconf package, so it should be able to drop new versions into the

"gtest" subdirectory without modification.

Java

* Fixed bug where Message.mergeFrom(Message) failed to merge extensions.

* Message interface has new method toBuilder() which is equivalent to

newBuilderForType().mergeFrom(this).

* All enums now implement the ProtocolMessageEnum interface.

* Setting a field to null now throws NullPointerException.

* Fixed tendency for TextFormat's parsing to overflow the stack when

parsing large string values. The underlying problem is with Java's

regex implementation (which unfortunately uses recursive backtracking

rather than building an NFA). Worked around by making use of possesive

quantifiers.

* Generated service classes now also generate pure interfaces. For a service

Foo, Foo.Interface is a pure interface containing all of the service's

defined methods. Foo.newReflectiveService() can be called to wrap an

instance of this interface in a class that implements the generic

RpcService interface, which provides reflection support that is usually

needed by RPC server implementations.

* RPC interfaces now support blocking operation in addition to non-blocking.

The protocol compiler generates separate blocking and non-blocking stubs

which operate against separate blocking and non-blocking RPC interfaces.

RPC implementations will have to implement the new interfaces in order to

support blocking mode.

* New I/O methods parseDelimitedFrom(), mergeDelimitedFrom(), and

writeDelimitedTo() read and write "delemited" messages from/to a stream,

meaning that the message size precedes the data. This way, you can write

multiple messages to a stream without having to worry about delimiting

them yourself.

* Throw a more descriptive exception when build() is double-called.

* Add a method to query whether CodedInputStream is at the end of the input

stream.

* Add a method to reset a CodedInputStream's size counter; useful when

reading many messages with the same stream.

* equals() and hashCode() now account for unknown fields.

Python

* Added slicing support for repeated scalar fields. Added slice retrieval and

removal of repeated composite fields.

* Updated RPC interfaces to allow for blocking operation. A client may

now pass None for a callback when making an RPC, in which case the

call will block until the response is received, and the response

object will be returned directly to the caller. This interface change

cannot be used in practice until RPC implementations are updated to

implement it.

* Changes to input_stream.py should make protobuf compatible with appengine.

2008-11-25 version 2.0.3:

protoc

* Enum values may now have custom options, using syntax similar to field

options.

* Fixed bug where .proto files which use custom options but don't actually

define them (i.e. they import another .proto file defining the options)

had to explicitly import descriptor.proto.

* Adjacent string literals in .proto files will now be concatenated, like in

C.

* If an input file is a Windows absolute path (e.g. "C:\foo\bar.proto") and

the import path only contains "." (or contains "." but does not contain

the file), protoc incorrectly thought that the file was under ".", because

it thought that the path was relative (since it didn't start with a slash).

This has been fixed.

C++

* Generated message classes now have a Swap() method which efficiently swaps

the contents of two objects.

* All message classes now have a SpaceUsed() method which returns an estimate

of the number of bytes of allocated memory currently owned by the object.

This is particularly useful when you are reusing a single message object

to improve performance but want to make sure it doesn't bloat up too large.

* New method Message::SerializeAsString() returns a string containing the

serialized data. May be more convenient than calling

SerializeToString(string*).

* In debug mode, log error messages when string-type fields are found to

contain bytes that are not valid UTF-8.

* Fixed bug where a message with multiple extension ranges couldn't parse

extensions.

* Fixed bug where MergeFrom(const Message&) didn't do anything if invoked on

a message that contained no fields (but possibly contained extensions).

* Fixed ShortDebugString() to not be O(n^2). Durr.

* Fixed crash in TextFormat parsing if the first token in the input caused a

tokenization error.

* Fixed obscure bugs in zero_copy_stream_impl.cc.

* Added support for HP C++ on Tru64.

* Only build tests on "make check", not "make".

* Fixed alignment issue that caused crashes when using DynamicMessage on

64-bit Sparc machines.

* Simplify template usage to work with MSVC 2003.

* Work around GCC 4.3.x x86_64 compiler bug that caused crashes on startup.

(This affected Fedora 9 in particular.)

* Now works on "Solaris 10 using recent Sun Studio".

Java

* New overload of mergeFrom() which parses a slice of a byte array instead

of the whole thing.

* New method ByteString.asReadOnlyByteBuffer() does what it sounds like.

* Improved performance of isInitialized() when optimizing for code size.

Python

* Corrected ListFields() signature in Message base class to match what

subclasses actually implement.

* Some minor refactoring.

* Don't pass self as first argument to superclass constructor (no longer

allowed in Python 2.6).

2008-09-29 version 2.0.2:

General

* License changed from Apache 2.0 to New BSD.

* It is now possible to define custom "options", which are basically

annotations which may be placed on definitions in a .proto file.

For example, you might define a field option called "foo" like so:

import "google/protobuf/descriptor.proto"

extend google.protobuf.FieldOptions {

optional string foo = 12345;

}

Then you annotate a field using the "foo" option:

message MyMessage {

optional int32 some_field = 1 [(foo) = "bar"]

}

The value of this option is then visible via the message's

Descriptor:

const FieldDescriptor* field =

MyMessage::descriptor()->FindFieldByName("some_field");

assert(field->options().GetExtension(foo) == "bar");

This feature has been implemented and tested in C++ and Java.

Other languages may or may not need to do extra work to support

custom options, depending on how they construct descriptors.

C++

* Fixed some GCC warnings that only occur when using -pedantic.

* Improved static initialization code, making ordering more

predictable among other things.

* TextFormat will no longer accept messages which contain multiple

instances of a singular field. Previously, the latter instance

would overwrite the former.

* Now works on systems that don't have hash_map.

Java

* Print @Override annotation in generated code where appropriate.

Python

* Strings now use the "unicode" type rather than the "str" type.

String fields may still be assigned ASCII "str" values; they will

automatically be converted.

* Adding a property to an object representing a repeated field now

raises an exception. For example:

# No longer works (and never should have).

message.some_repeated_field.foo = 1

Windows

* We now build static libraries rather than DLLs by default on MSVC.

See vsprojects/readme.txt for more information.

2008-08-15 version 2.0.1:

protoc

* New flags --encode and --decode can be used to convert between protobuf text

format and binary format from the command-line.

* New flag --descriptor_set_out can be used to write FileDescriptorProtos for

all parsed files directly into a single output file. This is particularly

useful if you wish to parse .proto files from programs written in languages

other than C++: just run protoc as a background process and have it output

a FileDescriptorList, then parse that natively.

* 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.

* Fixed absolute output paths on Windows.

* Allow trailing slashes in --proto_path mappings.

C++

* Reflection objects are now per-class rather than per-instance. To make this

possible, the Reflection interface had to be changed such that all methods

take the Message instance as a parameter. This change improves performance

significantly in memory-bandwidth-limited use cases, since it makes the

message objects smaller. Note that source-incompatible interface changes

like this will not be made again after the library leaves beta.

* Heuristically detect sub-messages when printing unknown fields.

* Fix static initialization ordering bug that caused crashes at startup when

compiling on Mac with static linking.

* Fixed TokenizerTest when compiling with -DNDEBUG on Linux.

* Fixed incorrect definition of kint32min.

* Fix bytes type setter to work with byte sequences with embedded NULLs.

* 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.

* Added info to Java POM that will be required when we upload the

package to a Maven repo.

Python

* MergeFrom(message) and CopyFrom(message) are now implemented.

* SerializeToString() raises an exception if the message is missing required

fields.

* Code organization improvements.

* Fixed doc comments for RpcController and RpcChannel, which had somehow been

swapped.

* Fixed text_format_test on Windows where floating-point exponents sometimes

contain extra zeros.

* Fix Python service CallMethod() implementation.

Other

* Improved readmes.

* VIM syntax highlighting improvements.

2008-07-07 version 2.0.0:

* First public release.