Abseil LTS branch, Aug 2023

Abseil LTS 20230802

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

• This release does not build in some configurations on several unsupported platforms, including FreeBSD, NetBSD, OpenBSD, and MinGW. 20230802.1 addresses this issue.

Baseline: fdf5be1
Cherry pick: 659b77b

Abseil LTS branch, Jan 2023, Patch 3

Abseil LTS 20230125.3

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)

Abseil LTS branch, Jan 2023, Patch 2

Abseil LTS 20230125.2

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)

Abseil LTS branch, Jan 2023, Patch 1

Abseil LTS 20230125.1

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)

Abseil LTS branch, Jan 2023

Abseil LTS 20230125

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

Abseil LTS branch, June 2022, Patch 1

Abseil LTS 20220623.1

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)

Abseil LTS branch, June 2022

Abseil LTS 20220623

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

Abseil LTS branch, Nov 2021

Abseil LTS 20211102

What's New:

• absl::Cord is now implemented as a b-tree. The new implementation offers improved performance in most workloads.
• absl::SimpleHexAtoi() has been added to strings library for parsing hexadecimal strings.

Breaking Changes:

• Bazel builds now depend on the bazelbuild/platforms repository. See Abseil's WORKSPACE file for an example of how to add this dependency.

Baseline: 2151058

Abseil LTS branch, March 2021, Patch 2

Abseil LTS 20210324.2

What's New:

• The cleanup library has been released. This library contains the control-flow-construct-like type absl::Cleanup which is used for executing a callback on scope exit.
• The numeric library now includes bits.h, a polyfill header containing implementations of C++20's bitwise math functions.
• Abseil now installs pkg-config files to make it easier to use Abseil with some other build systems.
• Abseil now respects the default CMake installation paths. Standard CMake variables like CMAKE_INSTALL_PREFIX can be used to change the installation path.

Breaking Changes:

• The empty absl::container target has been removed from the CMake build. This target had no effect and references to this target in user code can safely be removed.

Baseline: 997aaf3
Cherry pick: e1d388e (Patch 1)
Cherry pick: 278e0a0 (Patch 2)

Abseil LTS branch, March 2021, Patch 1

Abseil LTS 20210324.1

What's New:

• The cleanup library has been released. This library contains the control-flow-construct-like type absl::Cleanup which is used for executing a callback on scope exit.
• The numeric library now includes bits.h, a polyfill header containing implementations of C++20's bitwise math functions.
• Abseil now installs pkg-config files to make it easier to use Abseil with some other build systems.
• Abseil now respects the default CMake installation paths. Standard CMake variables like CMAKE_INSTALL_PREFIX can be used to change the installation path.

Breaking Changes:

• The empty absl::container target has been removed from the CMake build. This target had no effect and references to this target in user code can safely be removed.

Baseline: 997aaf3
Cherry pick: e1d388e (Patch 1)