Target Addresses

Every Pants target has an address, which is a combination of the BUILD file path and target name. Addresses are used in two main contexts:

  • To reference targets as dependencies in BUILD files,
  • From the command-line, to specify what targets to act on.

The following target addresses all specify the same single target.

  • The fully qualified target address is // plus the BUILD file's directory path plus target name:

    $ ./pants list //examples/src/java/org/pantsbuild/example/hello/main:main
    examples/src/java/org/pantsbuild/example/hello/main:main
    
  • The starting double-slash is optional if the target isn't in the build root directory:

    $ ./pants list examples/src/java/org/pantsbuild/example/hello/main:main
    examples/src/java/org/pantsbuild/example/hello/main:main
    

    It's idiomatic to omit the double-slash when possible. However it's required when referencing targets in the build root, so that the command-line parser can distinguish such targets from goal names: ./pants foo bar baz is ambiguous; ./pants foo //:bar //:baz is not. That said, it's not necessary, or even common, to have targets at the build root, and this practice is best avoided anyway.

  • The target name is optional if it is the same as the parent directory name:

    $ ./pants list examples/src/java/org/pantsbuild/example/hello/main
    examples/src/java/org/pantsbuild/example/hello/main:main
    

    It's idiomatic to omit the repetition of the target name in this case.

  • Relative paths and trailing forward slashes are ignored on the command-line to accommodate tab completion:

    $ ./pants list ./examples/src/java/org/pantsbuild/example/hello/main/
    examples/src/java/org/pantsbuild/example/hello/main:main
    

    Absolute paths are also allowed on the command-line, to support flexibility in scripting:

    $ pants goal list $REPO_ROOT/src/java/org/pantsbuild/example/hello/main
    src/java/org/pantsbuild/example/hello/main:main
    

These last two forms are not allowed in target addresses in BUILD files. They are just for command-line convenience.

You can reference another target in the same BUILD file by starting with a colon :targetname instead of specifying the whole path:

java_library(name='application', ...)
java_library(name='mybird',
  dependencies=[':application'],
)

Note that, apart from this shorthand, addresses in BUILD files are always relative to the buildroot, not to the referencing BUILD file.

Pants supports two globbing target selectors, as a convenience on the command-line. These forms are not allowed in BUILD files.

A trailing single colon specifies a glob of targets at the specified location:

$ ./pants list tests/python/pants_test/:
tests/python/pants_test:int-test
tests/python/pants_test:base_test
tests/python/pants_test:test_infra
tests/python/pants_test:test_maven_layout

A trailing double colon specifies a recursive glob of targets at the specified location:

$ ./pants list tests/python/pants_test/::
tests/python/pants_test:int-test
tests/python/pants_test:base_test
tests/python/pants_test:test_infra
tests/python/pants_test:test_maven_layout
tests/python/pants_test/base:base
...
tests/python/pants_test/tasks:sorttargets
tests/python/pants_test/testutils:testutils
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