Do not tickle TimestampGranularityMonitor for CONSTANT_METADATA artifacts. "Constant metadata" artifacts represent real files whose changes should be ignored by the build system. However, these artifacts were triggering the timestamp granularity checks in TimestampGranularityMonitor because the fact that they were "constant metadata" was not respected. Avoid this so that their regeneration does not cause the build to unnecessarily stall. One of these artifacts is the volatile workspace status file, which is unconditionally updated on each build. Before this fix, "blaze build" would get stuck for up to a second waiting for file system timestamps to catch up. With this fix, the artifact is ignored and the wait is gone. This problem is magnified on macOS where the default HFS+ file system only has second-level granularity. (This also affects Linux, but because current Linux file systems have milli/nanosecond-level granularity, the wait imposed by TimestampGranularityMonitor is minimal and thus not generally noticeable.) -- MOS_MIGRATED_REVID=137867586
{Fast, Correct} - Choose two
Bazel is a build tool that builds code quickly and reliably. It is used to build the majority of Google‘s software, and thus it has been designed to handle build problems present in Google’s development environment, including:
A massive, shared code repository, in which all software is built from source. Bazel has been built for speed, using both caching and parallelism to achieve this. Bazel is critical to Google's ability to continue to scale its software development practices as the company grows.
An emphasis on automated testing and releases. Bazel has been built for correctness and reproducibility, meaning that a build performed on a continuous build machine or in a release pipeline will generate bitwise-identical outputs to those generated on a developer's machine.
Language and platform diversity. Bazel's architecture is general enough to support many different programming languages within Google, and can be used to build both client and server software targeting multiple architectures from the same underlying codebase.
Find more background about Bazel in our FAQ.