Abseil LTS branch, July 2024

Abseil LTS 20240722.0

What's New:

• Added GoogleTest matchers for absl::Status. These matchers make it easier to write unit tests for code that uses absl::Status.

Breaking Changes:

• absl::AlphaNum no longer allows brace-initialization. This was never intended to be supported, nor is it recommended that absl::AlphaNum ever be spelled in user code.
• The deprecated symbol absl::kuint128max has been removed and should be replaced with absl::Uint128Max().
• absl::aligned_storage_t, which was a polyfill consistent with std::aligned_storage_t, has been removed. std::aligned_storage_t is deprecated in C++23. See https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1413r3.pdf for a suggested replacement.
• absl::StrJoin now has a absl::string_view overload. This allows for passing a collection of string-like objects without having to convert everything to the same type first. However, this may be a breaking change for users passing an explicit template argument to absl::StrJoin. In this case, simply remove the explicit template parameter.
• vlog_is_on.h is now a public header and is no longer included from log.h. To use VLOG_IS_ON(), absl/log/vlog_is_on.h must be included.

Known Issues

• None known at this time.

Baseline: 3358286
Cherry-pick: 2138590
Cherry-pick: 9a0743a
Cherry-pick: 4447c75

Abseil LTS branch, July 2024, Release Candidate 2

Abseil LTS 20240722, Release Candidate 2

What's New:

• Added GoogleTest matchers for absl::Status. These matchers make it easier to write unit tests for code that uses absl::Status.

Breaking Changes:

• absl::AlphaNum no longer allows brace-initialization. This was never intended to be supported, nor is it recommended that absl::AlphaNum ever be spelled in user code.
• The deprecated symbol absl::kuint128max has been removed and should be replaced with absl::Uint128Max().
• absl::aligned_storage_t, which was a polyfill consistent with std::aligned_storage_t, has been removed. std::aligned_storage_t is deprecated in C++23. See https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1413r3.pdf for a suggested replacement.
• absl::StrJoin now has a absl::string_view overload. This allows for passing a collection of string-like objects without having to convert everything to the same type first. However, this may be a breaking change for users passing an explicit template argument to absl::StrJoin. In this case, simply remove the explicit template parameter.
• vlog_is_on.h is now a public header and is no longer included from log.h. To use VLOG_IS_ON(), absl/log/vlog_is_on.h must be included.

Known Issues

• None known at this time.

Baseline: 3358286
Cherry-pick: 2138590
Cherry-pick: 9a0743a

Abseil LTS branch, July 2024, Release Candidate 1

Abseil LTS 20240722, Release Candidate 1

What's New:

• Added GoogleTest matchers for absl::Status. These matchers make it easier to write unit tests for code that uses absl::Status.

Breaking Changes:

• absl::AlphaNum no longer allows brace-initialization. This was never intended to be supported, nor is it recommended that absl::AlphaNum ever be spelled in user code.
• The deprecated symbol absl::kuint128max has been removed and should be replaced with absl::Uint128Max().
• absl::aligned_storage_t, which was a polyfill consistent with std::aligned_storage_t, has been removed. std::aligned_storage_t is deprecated in C++23. See https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1413r3.pdf for a suggested replacement.
• absl::StrJoin now has a absl::string_view overload. This allows for passing a collection of string-like objects without having to convert everything to the same type first. However, this may be a breaking change for users passing an explicit template argument to absl::StrJoin. In this case, simply remove the explicit template parameter.
• vlog_is_on.h is now a public header and is no longer included from log.h. To use VLOG_IS_ON(), absl/log/vlog_is_on.h must be included.

Known Issues

• None known at this time.

Baseline: 3358286

Abseil LTS branch, Jan 2024, Patch 2

Abseil LTS 20240116.2

What's New:

• Added absl::NoDestructor<T> to simplify defining static types that do not need to be destructed upon program exit.
• Added configurable verbose logging (also known as VLOG).
• Added absl::Overload(), which returns a functor that provides overloads based on the functors passed to it. Note that this functionality requires C++17 or newer.
• Bzlmod is now officially supported (previously it was supported by the community). Note that it may take several days after the release for it to become available in the Bazel Central Registry.

Breaking Changes:

• AbslHashValue() no longer accepts C-style arrays as a parameter. Previously the array would decay to a pointer type, which could lead to subtle, unintended bugs. The most common potential error is passing a C-string literal. After this change, these call-sites require wrapping the literal in absl::string_view.
• absl::weak_equality and absl::strong_equality have been removed. The corresponding std types were removed before C++20 was finalized (https://wg21.link/P1959R0).

Known Issues

• None known at this time.

Baseline: 10f3e61
Cherry pick: 4a2c633
Cherry pick: 3ab97e7 (Patch 1)
Cherry pick: d7aaad8 (Patch 2)

Abseil LTS branch, Jan 2024, Patch 1

Abseil LTS 20240116.1

What's New:

• Added absl::NoDestructor<T> to simplify defining static types that do not need to be destructed upon program exit.
• Added configurable verbose logging (also known as VLOG).
• Added absl::Overload(), which returns a functor that provides overloads based on the functors passed to it. Note that this functionality requires C++17 or newer.
• Bzlmod is now officially supported (previously it was supported by the community). Note that it may take several days after the release for it to become available in the Bazel Central Registry.

Breaking Changes:

• AbslHashValue() no longer accepts C-style arrays as a parameter. Previously the array would decay to a pointer type, which could lead to subtle, unintended bugs. The most common potential error is passing a C-string literal. After this change, these call-sites require wrapping the literal in absl::string_view.
• absl::weak_equality and absl::strong_equality have been removed. The corresponding std types were removed before C++20 was finalized (https://wg21.link/P1959R0).

Known Issues

• None known at this time.

Baseline: 10f3e61
Cherry pick: 4a2c633
Cherry pick: 3ab97e7 (Patch 1)

Abseil LTS branch, Aug 2023, Patch 2

Abseil LTS 20230802.2

What's New:

• Added the nullability library for designating the expected nullability of pointers. Currently these serve as annotations only, but it is expected that compilers will one day be able to use these annotations for diagnostic purposes.
• Added the prefetch library as a portable layer for moving data into caches before it is read.
• Abseil's hash tables now detect many more programming errors in debug and sanitizer builds.
• Abseil's synchronization objects now differentiate absolute waits (when passed an absl::Time) from relative waits (when passed an absl::Duration) when the underlying platform supports differentiating these cases. This only makes a difference when system clocks are adjusted.
• Abseil's flag parsing library includes additional methods that make it easier to use when another library also expects to be able to parse flags.
• absl::string_view is now available as a smaller target, @com_google_absl//absl/strings:string_view, so that users may use this library without depending on the much larger @com_google_absl//absl/strings target.

Breaking Changes:

• None known at this time.

Known Issues

• None known at this time.

Baseline: fdf5be1
Cherry pick: 659b77b
Cherry pick: fb3621f (Patch 1)
Cherry pick: 11e1e5c (Patch 2)

Abseil LTS branch, Jan 2023, Patch 4

Abseil LTS 20230125.4

What's New:

• The Abseil logging library has been released. This library provides facilities for writing short text messages about the status of a program to stderr, disk files, or other sinks (via an extension API). See the logging library documentation for more information.
• An extension point, AbslStringify(), allows user-defined types to seamlessly work with Abseil's string formatting functions like absl::StrCat() and absl::StrFormat().
• A library for computing CRC32C checksums has been added.
• Floating-point parsing now uses the Eisel-Lemire algorithm, which provides a significant speed improvement.
• The flags library now provides suggestions for the closest flag(s) in the case of misspelled flags.
• Using CMake to install Abseil now makes the installed artifacts (in particular absl/base/options.h) reflect the compiled ABI.

Breaking Changes:

• Abseil now requires at least C++14 and follows Google's Foundational C++ Support Policy. See this table for a list of currently supported versions compilers, platforms, and build tools.
• The legacy spellings of the thread annotation macros/functions (e.g. GUARDED_BY()) have been removed by default in favor of the ABSL_ prefixed versions (e.g. ABSL_GUARDED_BY()) due to clashes with other libraries. The compatibility macro ABSL_LEGACY_THREAD_ANNOTATIONS can be defined on the compile command-line to temporarily restore these spellings, but this compatibility macro will be removed in the future.

Known Issues

• The Abseil logging library in this release is not a feature-complete replacement for glog yet. VLOG and DFATAL are examples of features that have not yet been released.

Baseline: a69b0ae
Cherry pick: 35e8e3f (Patch 1)
Cherry pick: a0f9b46 (Patch 1)
Cherry pick: 2de126c (Patch 2)
Cherry pick: 807763a (Patch 3)
Cherry pick: 96074ab (Patch 4)

Abseil LTS branch, June 2022, Patch 2

Abseil LTS 20220623.2

What's New:

• Added absl::AnyInvocable, a move-only function type.
• Added absl::CordBuffer, a type for buffering data for eventual inclusion an absl::Cord, which is useful for writing zero-copy code.
• Added support for command-line flags of type absl::optional<T>.

Breaking Changes:

• CMake builds now use the flag ABSL_BUILD_TESTING (default: OFF) to control whether or not unit tests are built.
• The ABSL_DEPRECATED macro now works with the GCC compiler. GCC users that are experiencing new warnings can use -Wno-deprecated-declatations silence the warnings or use -Wno-error=deprecated-declarations to see warnings but not fail the build.
• ABSL_CONST_INIT uses the C++20 keyword constinit when available. Some compilers are more strict about where this keyword must appear compared to the pre-C++20 implementation.
• Bazel builds now depend on the bazelbuild/bazel-skylib repository. See Abseil's WORKSPACE file for an example of how to add this dependency.

Other:

• This will be the last release to support C++11. Future releases will require at least C++14.

Baseline: 273292d
Cherry pick: 8c0b94e (Patch 1)
Cherry pick: 704de40 (Patch 2)

Abseil LTS branch, Jan 2024

Abseil LTS 20240116.0

What's New:

• Added absl::NoDestructor<T> to simplify defining static types that do not need to be destructed upon program exit.
• Added configurable verbose logging (also known as VLOG).
• Added absl::Overload(), which returns a functor that provides overloads based on the functors passed to it. Note that this functionality requires C++17 or newer.
• Bzlmod is now officially supported (previously it was supported by the community). Note that it may take several days after the release for it to become available in the Bazel Central Registry.

Breaking Changes:

• AbslHashValue() no longer accepts C-style arrays as a parameter. Previously the array would decay to a pointer type, which could lead to subtle, unintended bugs. The most common potential error is passing a C-string literal. After this change, these call-sites require wrapping the literal in absl::string_view.
• absl::weak_equality and absl::strong_equality have been removed. The corresponding std types were removed before C++20 was finalized (https://wg21.link/P1959R0).

Known Issues

• None known at this time.

Baseline: 10f3e61
Cherry pick: 4a2c633

Abseil LTS branch, Aug 2023, Patch 1

Abseil LTS 20230802.1

What's New:

• Added the nullability library for designating the expected nullability of pointers. Currently these serve as annotations only, but it is expected that compilers will one day be able to use these annotations for diagnostic purposes.
• Added the prefetch library as a portable layer for moving data into caches before it is read.
• Abseil's hash tables now detect many more programming errors in debug and sanitizer builds.
• Abseil's synchronization objects now differentiate absolute waits (when passed an absl::Time) from relative waits (when passed an absl::Duration) when the underlying platform supports differentiating these cases. This only makes a difference when system clocks are adjusted.
• Abseil's flag parsing library includes additional methods that make it easier to use when another library also expects to be able to parse flags.
• absl::string_view is now available as a smaller target, @com_google_absl//absl/strings:string_view, so that users may use this library without depending on the much larger @com_google_absl//absl/strings target.

Breaking Changes:

• None known at this time.

Known Issues

• None known at this time.

Baseline: fdf5be1
Cherry pick: 659b77b
Cherry pick: fb3621f (Patch 1)