What's New

Pants 2.15 brings support for several new features:

Environments

Pants now supports alternate execution "environments" for build actions. These "environments" can be explicitly
configured as desired via several new target types (including having multiple environments of the same type).
The new environment field on many targets tells Pants which environment to use for a particular target.

Pants previously supported local execution (which is now configured by the local_environment target type) and
remote execution via the Remote Execution API (which is now configured by the remote_environment target type).

New in Pants 2.15 is support for executing build actions within a Docker container configured via the
docker_environment target type.

See the Environments documentation for more information.

Test Batching

./pants test now supports batching compatible tests together so that they execute in the same process.
This can improve performance of test execution by sharing test environment setup across multiple test files,
but must be balanced against the impact on caching and concurrency.

The Python backend is the first user of the test batching support.

New goal: fix

The fix goal has been added to run tools which generally will perform more invasive changes on your source
files than the fmt goal. The fmt goal remains for tools which merely format code without making
semantic changes.

Backends

Python

Several changes have been made to the Python backend:

• Support for the new Environments feature. Relevant targets now have a new environment field
  to configure which environment to use for that target.
• Batched execution of pytest tests.
• Support for lcov coverage format.
• Support for pyright typechecking.
• Python lockfiles are now represented in the build graph via synthetic targets.
• Upgrades to default version of several tools including coverage and Flake8.

Go

The Go backend received several changes including:

• Basic support for Cgo
• Coverage reports can be generated in HTML and not just the raw data file used by go tool cover.
• Support for the golangci-lint linter.
• Support for multiple go_mod targets in same repository.
• A new go-generate custom goal to run go generate on any //go:generate instructions in a package.
• $GOROOT/bin is now prepended to PATH when running tests to enable them to easily find the go binary for
  the Go toolchain in use.

Note: Due to certain changes in Go v1.20, Pants 2.15.x and earlier Pants versions will not work with Go v1.20
and later releases. Instead, use Pants v2.16.x or later Pants versions to support Go v1.20 and later releases.

New: OpenAPI

The new OpenAPI backend provides support for linting OpenAPI API specifications using the spectral tool
and generating Java code from the OpenAPI specifications.

Enable the pants.backend.experimental.openapi backend for base OpenAPI support,
the pants.backend.experimental.openapi.lint.spectral backend for linting support, and
the pants.backend.experimental.openapi.codegen.java backend for Java code generation support.

Plugin API changes

Several changes were made to the Plugin API including the changes highlighted below. Read the
Plugin upgrade guide for a full description
of the changes highlighted below (as well as other changes not highlighted here), including how to migrate
existing plugins.

Formatters / Linters

The schema used for formatters and linters has been changed in order to allow for formatters and linters which
do not require a target on which to operate. See the applicable section of the Plugin upgrade guide
for the specific changes.

Batched Tests

The plugin API used by the test goal has been changed significantly to support the explicit batching of tests. See the
applicable section of the Plugin upgrade guide
for the specific changes.

Synthetic Targets

Plugins may now add "synthetic targets" to the build graph to create freestanding targets programmatically.
These synthetic targets can also be generator targets in order to further create generated targets. See the
plugin documentation for the Synthetic Targets API
for more information.