Announcements

• Protobuf News may include additional announcements or pre-announcements for upcoming changes.
• Migration Guide may include additional guidance for breaking changes.

Bazel

• Add Bazel9 test (90ad7e9)
• Bazel 9 tests for csharp, hpb, objc, php, python, rust and upb (f9e028f)

Compiler

• Make default_symbol_visibility STRICT in edition 2026 (fcd68c5)
• Add deprecation warnings for (py|cc|java)_generic_service. (517be42)
• Disallow reserving field number INT_MAX. (933c522)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• Feat: --<lang>_prefix cli option (#24824) (92dd27c)
• Enforce proto limits in the descriptor by default for EDITION_2026. (d8520d9)
• Fix: Apply path traversal guard to WriteAllToZip() matching WriteAllToDisk() (#27171) (28bef98)
• Add an enforce_proto_limits feature which will be implemented in Edition 2026. (5ddd524)

C++

• Disable option sub-location mapping in open-source builds. (1d8a656)
• Add json_options.proto and json_enumvalue_options.proto and/or gencode derived from them to release artifacts (15e9334)
• Add deprecation warning for Reflection::GetEnum() and Reflection::GetRepeatedEnum(). (0bca288)
• Migrate top-level protobuf unittest protos from Edition 2024 to Edition 2026. (271ca53)
• Util: validate Duration/Timestamp in TimeUtil::FromString against spec limits (#27443) (e337495)
• Make default_symbol_visibility STRICT in edition 2026 (fcd68c5)
• Use the direct map reflection API when converting message to JSON, if the repeated field reflection is not valid. (e75aac3)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• Fix(cpp): stop TextFormat iteration if output stream fails (#26237) (2718dd5)
• Enforce proto limits in the descriptor by default for EDITION_2026. (d8520d9)
• Add an enforce_proto_limits feature which will be implemented in Edition 2026. (5ddd524)
• Workaround for attribute handling bug in gcc < 13 (ba10a4e)
• Fix confusing error message for map value type name conflicts (7864b85)
• C++Proto JSON: Align behavior on the type.proto path with the descriptor.proto path (0bc1f14)

Java

• Add json_options.proto and json_enumvalue_options.proto and/or gencode derived from them to release artifacts (15e9334)
• Json/java: add json_name enumval support (bff6ed1)
• Make Timestamps.parse() attempt non-lenient parsing first and warning if this fails. (d5e039a)
• Add a warning for potential OneofDescriptor collisions prior to Q1 2027 breaking changes. (ab69831)
• Make default_symbol_visibility STRICT in edition 2026 (fcd68c5)
• Reject negative size in mergeDelimitedFrom (#28097) (c56cd5b)
• Add deprecation warnings for (py|cc|java)_generic_service. (517be42)
• Update Java protobuf generator to use Objects.requireNonNull (31ef11c)
• Use natural String comparison instead of UTF-8 ByteString comparison for sorting map keys in JsonFormat. (ae1faee)
• Add option to enable strict JSON parsing in Protobuf Java JsonFormat. (40825a1)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• Remove experimental FieldOrder enum. (ec52338)
• Optimize GeneratedMessage.ExtendableBuilder to avoid temporary allocations when merging empty extendable messages. (a37dbd6)
• Stop using sun.misc.Unsafe in isValidUtf8 paths. (421d745)
• Use String#encodedLength on JDK versions that support it (efca121)
• Add an enforce_proto_limits feature which will be implemented in Edition 2026. (5ddd524)
• Java: limit numeric string length before BigDecimal parsing (#26908) (25e7005)
• Validate java package and class against injection risks. (f8514d8)

Csharp

• Cache custom JSON enum names in JsonParser using Lazy. (156d42d)
• Csharp: add support for custom json strings for enum values (f11aac4)
• Validate language-specific namespace options in code generators (#28667) (34e959b)
• Make default_symbol_visibility STRICT in edition 2026 (fcd68c5)
• Advertise that C# supports Edition 2026, and move C# Nullable Reference Type support into that edition. (a1f718c)
• First implementation of C# nullable reference types enablement using the current (unreleased) edition. (7a732d1)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• Csharp: propagate recursion depth into JsonReplayTokenizer to honor Any nesting limit (#26835) (cee45bf)
• Fix csharp string interpolation in Timestamp.ToDateTime() exception message (#26341) (a298282)

Objective-C

• [ObjC] Carry recursion depth across MessageSet item parsing (#27571) (f89baed)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• [ObjC] Add DEBUG-only validations to extension values in GPBMessage, along with tests. (290a537)

Rust

• Re-export to google-protobuf crate in 0.x.y for 36.0 and above (96e772f)
• Remove -release suffix from Rust Crates.io release if minor version >= 36 (e7b3391)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• RustProto: Add the ability to iterate over the muts of a repeated message-typed field. (70590a5)
• See also UPB changes below, which may affect Rust.

Python

• Add json_options.proto and json_enumvalue_options.proto and/or gencode derived from them to release artifacts (15e9334)
• Emit future warning when mutating GetOptions() in OSS (2255541)
• Emit deprecation warning when comparing descriptor containers with unrecognized types in OSS (5865e6b)
• Migrate top-level protobuf unittest protos from Edition 2024 to Edition 2026. (271ca53)
• Configure extra compile args in setup.py (#28264) (3aa022a)
• Python: fix heap-use-after-free in MapIterator after map.clear() (#27257) (9e9dbae)
• Add PyDescriptorPool_FromSharedPool(std::shared_ptr) API (abdf212)
• Fix memory leak in PyUpb_Descriptor_GetExtensionRanges (3d31b0f)
• Warn on out-of-range pop index in upb repeated fields. (a70d121)
• Support assigning repeated scalar fields using Python Buffer API. (ea40f1d)
• Fix Pure Python map<string, ...> key handling for bytes lookups. (156a0b8)
• Change Python DescriptorDatabase FindFileContainingSymbol() to accept leading "." to match DescriptorPool and other languages (e86e536)
• Faster Python cpp protos assignment to bytes/string fields. (593ab17)
• Serialize length-prefixed protos once (#27252) (e090f8a)
• [py/upb] Make GetOptions() return immutable options for scalar type. UPB will raise a TypeError when options returned GetOptions() by is mutated. (403d429)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• Add mutex protection to DescriptorPool caches. (cecbbf4)
• Refactor container comparison function in py/C++ and py/upb to return enum instead of integer. (c857f49)
• Py JSON: Fix issue with depth enforcement on Struct/Value WKT paths. (cfcc433)
• Fix RepeatedContainer_pop to raise IndexError for out-of-bounds indices. (78a09ad)

PHP

• Support custom JSON enum names in PHP (49b3b18)
• Remove total_bytes_limit from pure PHP CodedInputStream. (e171c67)
• Validate language-specific namespace options in code generators (#28667) (34e959b)
• Fix PHP update_reserved_words.sh formatting and CI idempotency test (eff2323)
• Feat(php): script for updating php reserved words (#27456) (47c8651)
• [PHP] - Add configurable recursion_limit to mergeFromString / serializeToString (#27874) (5c5ee3c)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)
• Clarify FieldMask JSON warnings/errors in the situation of fields which aren't round-trip representable in JSON format. (0488596)
• Add an enforce_proto_limits feature which will be implemented in Edition 2026. (5ddd524)

PHP C-Extension

• Support custom JSON enum names in PHP (49b3b18)
• Feat(php): script for updating php reserved words (#27456) (47c8651)
• [PHP] - Add configurable recursion_limit to mergeFromString / serializeToString (#27874) (5c5ee3c)
• See also UPB changes below, which may affect PHP C-Extension.

Ruby

• Validate language-specific namespace options in code generators (#28667) (34e959b)
• Drop support for Ruby 3.1 (7008dd1)
• Add bazel targets for standalone plugin binaries (#23919) (81880fa)

UPB (Python/PHP/Ruby C-Extension)

• Json/upb: Implement json EnumValueName for upb (0e8519e)
• Avoid UB in upb by switching to the XCT section, which will run our constructors before the compiler-generated initializers. (58e5ac8)
• [py/upb] Make GetOptions() return immutable options for scalar type. UPB will raise a TypeError when options returned GetOptions() by is mutated. (403d429)
• Clarify FieldMask JSON warnings/errors in the situation of fields which aren't round-trip representable in JSON format. (0488596)
• Add Bazel9 test (90ad7e9)
• Fixed two GCC-only issues around upb's generated extension registry. (d56b385)
• Fix RepeatedContainer_pop to raise IndexError for out-of-bounds indices. (78a09ad)

Other

• Fix typo in legacy_rust (daf4964)
• Add JSON and CPP option protos to C++ toolchain blacklisted_protos (c4846de)
• Remove fallback behavior (2d3c0d3)
• Add deprecation warning for internal_py_proto_library prior to Q1 2027 breaking changes. (a8d0be3)