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constraint

Unified constraint rule that defines both a constraint setting and its possible values. Values are exposed as subtargets, e.g., cfg//:os[linux].

Function Signature​

def constraint(
    *,
    name: str,
    default_target_platform: None | str = None,
    target_compatible_with: list[str] = [],
    compatible_with: list[str] = [],
    exec_compatible_with: list[str] = [],
    visibility: list[str] = [],
    within_view: list[str] = ["PUBLIC"],
    metadata: OpaqueMetadata = {},
    tests: list[str] = [],
    modifiers: OpaqueMetadata = [],
    _apple_platforms: dict[str, str] = {},
    default: str,
    values: list[str],
) -> None

Parameters​

  • name: (required)

    name of the target

  • default_target_platform: (defaults to: None)

    specifies the default target platform, used when no platforms are specified on the command line

  • target_compatible_with: (defaults to: [])

    a list of constraints that are required to be satisfied for this target to be compatible with a configuration

  • compatible_with: (defaults to: [])

    a list of constraints that are required to be satisfied for this target to be compatible with a configuration

  • exec_compatible_with: (defaults to: [])

    a list of constraints that are required to be satisfied for this target to be compatible with an execution platform

  • visibility: (defaults to: [])

    a list of visibility patterns restricting what targets can depend on this one

  • within_view: (defaults to: ["PUBLIC"])

    a list of visibility patterns restricting what this target can depend on

  • metadata: (defaults to: {})

    a key-value map of metadata associated with this target

  • tests: (defaults to: [])

    a list of targets that provide tests for this one

  • modifiers: (defaults to: [])

    an array of modifiers associated with this target

  • default: (required)

    Default value (must be one of the values).

  • values: (required)

    List of value names.

Examples​


constraint(
    name = "os",
    values = ["linux", "macos", "windows"],
    default = "linux",
)