The Bazel team is happy to announce a new version of Bazel, Bazel 0.26.

Incompatible changes

• --incompatible_windows_escape_jvm_flags is enabled by default, and removed.

• --incompatible_windows_style_arg_escaping is enabled by default.

• --incompatible_no_output_attr_default is enabled by default.

• --incompatible_depset_union is enabled by default.

• --incompatible_disable_genrule_cc_toolchain_dependency removed

• --Incompatible_disallow_rule_execution_platform_constraints_allowed: When enabled, disallows the use of the execution_platform_constraints_allowed attribute when defining new rules.

• --incompatible_disable_objc_provider_resources is now enabled by default.

Apple

• The --ios_multi_cpus, --watchos_cpus, --macos_cpus and --tvos_cpus are now additive. This means that you can now split the --ios_multi_cpus=arm64,armv7 into --ios_multi_cpus=arm64 and --ios_multi_cpus=armv7.

• Add --incompatible_objc_framework_cleanup to control whether to enable some objc framework cleanup that changes the API. Specifically, the cleanup changes the objc provider API pertaining to frameworks. This change is expected to be transparent to most users unless they write their own Starlark rules to handle frameworks. See https://github.com/bazelbuild/bazel/issues/7594 for details.

• objc_library does not support resource attributes any more. Please read #7594 for more info.

Android

• Android resource conflicts will no longer be reported between a strong attr resource and a weak attr resource, if the weak attr does not have format specified.

• Added support for compiling against fully qualified R classes from aar_import dependencies.

C++

• Allow debugging C++ features logic

• Add new options --cs_fdo_instrument and --cs_fdo_profile to support LLVM's context-sensitive FDO (CSFDO).

• Bazel C++ compile/link Starlark API. Can be used with experimental flag --experimental_cc_skylark_api_enabled_packages.

• cc_toolchain.static_runtime_lib and cc_toolchain.dynamic_runtime_lib are now exposed to Starlark.

• C++ Starlark API for compilation and linking is no longer whitelisted

• Incompatible flag --incompatible_make_thinlto_command_lines_standalone has been added. See #6791 for details.

• Feature disable_whole_archive_for_static_lib has been added to allow turning off legacy_whole_archive for individual targets. #7362

Python

• Fixed an issue where some py_runtimes were incompatible with using --build_python_zip (#5104).

Starlark

• The flag --incompatible_restrict_named_params is added. Buildifier will soon be updated to automatically fix this in your code.

• The flag --incompatible_no_kwargs_in_build_files is added. It fixes a bug where the **kwarg notation was allowed in BUILD files.

• The flag --incompatible_static_name_resolution_in_build_files is added. This fixes a bug where invalid code was silently accepted.

• The flag --incompatible_disallow_old_octal_notation is added. It removes a deprecated notation for octal numbers. Buildifier can update your code automatically.

• struct.to_proto() can now convert dictionaries into proto3 text message.

• The glob function has a new argument allow_empty. When set to False (this will be the default in the future), the glob fails when it doesn't match anything. Please explicitly set allow_empty = True to the globs that need it.

Windows

• Windows, Python: the new --incompatible_windows_escape_python_args flag (false by default) builds py_binary and py_test targets with correct command line argument escaping. Similar to #7486 but for py_* rules.

Other changes

• cquery supports --output=build

• Generated Go protobufs now depend on //net/proto2/go:proto_gendeps instead of //net/proto2/go:proto

• Added --incompatible_remove_binary_profile to disable the old binary profiles. Instead use the JSON profile format: https://docs.bazel.build/versions/0.26.0/skylark/performance.html#json-profile

• Introducing --execution_log_binary_file and --execution_log_json_file that output a stable sorted execution log. They will offer a stable replacement to --experimental_execution_log_file.

• New platform_mappings ability to allow gradual flag to platforms/toolchains migration. See also #6426

• --tls_enabled flag is deprecated. Please provide grpcs as a scheme in the URLs if TLS should be used for a remote connection.

Community

• Alex Eagle gave a talk at ng-conf: The Bazel Opt-in Preview is Here!

• The latest release of rules_haskell includes many new improvements, including an initial Windows support.

• The latest Buildifier release includes Windows binaries, as well as a JSON output for diagnostics.

• A new release of the Visual Studio Code plugin for Bazel was released.

• Natan Silnitsky gave the talk How to successfully migrate to Bazel from Maven or Gradle at the Java Eastern Europe Conference.

This release contains contributions from many people at Google, as well as Benjamin Peterson, Brian Topping, clyang82, Dave Lee, George Gensure, Greg, Guro Bokum, Keith Smiley, Max Vorobev, Michael Hackner, Robert Brown, Robert Sayre, Ryan Beasley, and Yannic.