Add blog post for Bazel 4.2.0.

_posts/2021-08-18-bazel-4.2.md

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+---
+layout: posts
+title: "Bazel 4.2"
+authors:
+  - katre
+---
+
+Bazel 4.2 is a minor release as part of Bazel’s first LTS release. It is fully backward compatible with Bazel 4.0 and 4.1 and contains selected changes by the Bazel community and Google engineers.
+
+## Starlark
+
+* `required_providers` is now exposed to Starlark Defined Aspects (as part of work towards [#11736](https://github.com/bazelbuild/bazel/issues/11736)).
+
+
+## Configurability
+
+* The "unknown key" error for .bazelrc with Starlark flags has been fixed. ([#11301](https://github.com/bazelbuild/bazel/issues/11301))
+* The `cquery` command now inherits from `bazel test`, not `bazel build`. ([#13428](https://github.com/bazelbuild/bazel/issues/13428))
+* The `test` exec group now inherits properties from the default exec group. ([#13459](https://github.com/bazelbuild/bazel/issues/13459))
+* The `config_setting` visibility enforcement has been enabled with the  `--incompatible_enforce_config_setting_visibility` flag. ([#12932](https://github.com/bazelbuild/bazel/issues/12932))
+* The exit code is used to signal when errors are reported on invalid `aquery --output` [(#13660](https://github.com/bazelbuild/bazel/pull/13660)).
+* `label_flag` and `label_setting` now do not depend  on the default value. ([#11291](https://github.com/bazelbuild/bazel/issues/11291))
+
+## Apple
+
+* The basic Unix toolchain now works on Apple Silicon without Xcode installed. ([#13514](https://github.com/bazelbuild/bazel/issues/13514))
+* macOS loadable bundles no longer strip all symbols. ([#11869](https://github.com/bazelbuild/bazel/issues/11869))
+* `DEFAULT_MACOS_CPU` has been updated to match the host. ([#12671](https://github.com/bazelbuild/bazel/issues/12671))
+
+## CC
+
+* Bazel can now be built on Linux systems which use a minimal C standard library. ([#12460](https://github.com/bazelbuild/bazel/issues/12460))
+
+## Android
+
+* `aar_import` now exports proguard specs. ([#3778](https://github.com/bazelbuild/bazel/issues/3778))
+* Android rules now use version 0.23.0 of Bazel Android tools.
+* The minimum version of the Android SDK build tools is now 30.0.0.
+* `.aar` files can now be extracted. ([#13092](https://github.com/bazelbuild/bazel/issues/13092))
+* `tools/android` no longer depends on the presence of Python 2. ([#10127](https://github.com/bazelbuild/bazel/issues/10127))
+
+## Java
+
+* The Java Allocation Instrumenter library was updated to fix issues with JDK11+. ([#13726](https://github.com/bazelbuild/bazel/issues/13726))
+* Java now has coverage for external files.  ([#13376](https://github.com/bazelbuild/bazel/issues/13376))
+
+## Python
+
+* `stub_shebang` has been added to `py_runtime`. ([#8685](https://github.com/bazelbuild/bazel/issues/8685))
+
+## Windows
+
+* The threshold for long path shortening is now `MAX_PATH - 4`. ([#12310](https://github.com/bazelbuild/bazel/issues/12310))
+* Symlink creation on older Windows versions has been fixed. ([#13169](https://github.com/bazelbuild/bazel/issues/13169))
+* Windows developer mode symlinks have been fixed. ([#13169](https://github.com/bazelbuild/bazel/issues/13169))
+
+## Actions and Execution
+
+* Empty virtual actions no longer crash. ([#12816](https://github.com/bazelbuild/bazel/issues/12816))
+* A race condition that occurred when reporting action progresses is now fixed. ([#13713](https://github.com/bazelbuild/bazel/issues/13713))
+* DynamicSpawnStrategy crashes have been fixed. ([#13149](https://github.com/bazelbuild/bazel/issues/13149))
+* Interrupted status messages are not suppressed during pool closure. ([#13512](https://github.com/bazelbuild/bazel/issues/13512))
+
+### Workers
+
+* A bug in `WorkRequestHandler` that caused hanging workers has been fixed.
+* Workers now restart on flags that affect their creation/behaviour.
+* The default worker JSON protocol handler not allowing unknown fields, and a crash bug have been fixed. ([#13240](https://github.com/bazelbuild/bazel/issues/13240))
+* Workers can now finish lost races without delaying dynamic execution.
+
+### Remote execution
+
+* Bug fixes
+    * Remote strategy is not registered if remote execution is not available. ([#13340](https://github.com/bazelbuild/bazel/issues/13340), [#13487](https://github.com/bazelbuild/bazel/issues/13487))
+    * The progress bar shows "Scheduling" state while the action is actually hitting the remote cache and downloading outputs. [(#13531](https://github.com/bazelbuild/bazel/issues/13531))
+    * Bazel may have crashed with "Too many open files" when writing to local disk cache. [(#13435](https://github.com/bazelbuild/bazel/issues/13435))
+    * The XML generation spawn is executed even if test.xml is already generated when built with `--remote_download_minimal`. ([#12554](https://github.com/bazelbuild/bazel/issues/12554))
+* Improvements
+    * The `remoteCacheable` key has been added to the execution log.
+    * An `--experimental_capture_corrupted_outputs` flag has been added.
+    * The progress bar now displays download progress when remote execution is enabled.
+    * The remote cache no longer uploads empty output.
+
+This release contains contributions from many people at Google, as well as Benjamin Peterson, bromano, Christopher Sauer, Daniel Wagner-Hall, George Gensure, Johannes Abt, Keith Smiley, Kevin Hogeland, Ryan Beasley, ThomasCJY, Trustin Lee, Ulf Adams, Vertexwahn, and Yuval Kaplan.
+