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)

Abseil LTS branch, March 2021

Abseil LTS 20210324.0

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

Abseil LTS branch, Sept 2020, Patch 3

Abseil LTS 20200923, Patch 3

What's New:

• absl::StatusOr<T> has been released. See our blog
  post for more information.
• Abseil Flags reflection interfaces have been released.
• Abseil Flags memory usage has been significantly optimized.
• Abseil now supports a "hardened" build mode. This build mode enables
  runtime checks that guard against programming errors that may lead
  to security vulnerabilities.

Notable Fixes:

• Sanitizer dynamic annotations like AnnotateRWLockCreate that are
  also defined by the compiler sanitizer implementation are no longer
  also defined by Abseil.
• Sanitizer macros are now prefixed with ABSL_ to avoid naming collisions.
• Sanitizer usage is now automatically detected and no longer requires
  macros like ADDRESS_SANITIZER to be defined on the command line.

Breaking Changes:

• Abseil no longer contains a dynamic_annotations library. Users
  using a supported build system (Bazel or CMake) are unaffected by
  this, but users manually specifying link libraries may get an error
  about a missing linker input.

Baseline: 7680a5f
Cherry pick: bd0de71 (Patch 1)
Cherry pick: 0f3bb46 (Patch 2)
Cherry pick: 6f9d96a (Patch 3)

Abseil LTS branch, Sept 2020, Patch 2

Abseil LTS 20200923, Patch 2

What's New:

• absl::StatusOr<T> has been released. See our blog
  post for more information.
• Abseil Flags reflection interfaces have been released.
• Abseil Flags memory usage has been significantly optimized.
• Abseil now supports a "hardened" build mode. This build mode enables
  runtime checks that guard against programming errors that may lead
  to security vulnerabilities.

Notable Fixes:

• Sanitizer dynamic annotations like AnnotateRWLockCreate that are
  also defined by the compiler sanitizer implementation are no longer
  also defined by Abseil.
• Sanitizer macros are now prefixed with ABSL_ to avoid naming collisions.
• Sanitizer usage is now automatically detected and no longer requires
  macros like ADDRESS_SANITIZER to be defined on the command line.

Breaking Changes:

• Abseil no longer contains a dynamic_annotations library. Users
  using a supported build system (Bazel or CMake) are unaffected by
  this, but users manually specifying link libraries may get an error
  about a missing linker input.

Baseline: 7680a5f
Cherry pick: bd0de71 (Patch 1)
Cherry pick: 0f3bb46 (Patch 2)

Abseil LTS branch, Sept 2020, Patch 1

Abseil LTS 20200923, Patch 1

What's New:

• absl::StatusOr<T> has been released. See our blog
  post for more information.
• Abseil Flags reflection interfaces have been released.
• Abseil Flags memory usage has been significantly optimized.
• Abseil now supports a "hardened" build mode. This build mode enables
  runtime checks that guard against programming errors that may lead
  to security vulnerabilities.

Notable Fixes:

• Sanitizer dynamic annotations like AnnotateRWLockCreate that are
  also defined by the compiler sanitizer implementation are no longer
  also defined by Abseil.
• Sanitizer macros are now prefixed with ABSL_ to avoid naming collisions.
• Sanitizer usage is now automatically detected and no longer requires
  macros like ADDRESS_SANITIZER to be defined on the command line.

Breaking Changes:

• Abseil no longer contains a dynamic_annotations library. Users
  using a supported build system (Bazel or CMake) are unaffected by
  this, but users manually specifying link libraries may get an error
  about a missing linker input.

Baseline: 7680a5f
Cherry picks: bd0de71 (Patch 1)