Distribution.Types.ComponentRequestedSpec

Documentation

Note: Buildable versus requested versus enabled components

What's the difference between a buildable component (ala componentBuildable), a requested component (ala componentNameRequested), and an enabled component (ala componentEnabled)?

A component is buildable if, after resolving flags and conditionals, there is no buildable: False property in it. This is a static property that arises from the Cabal file and the package description flattening; once we have a PackageDescription buildability is known.

A component is requested if a user specified, via a the flags and arguments passed to configure, that it should be built. E.g., --enable-tests or --enable-benchmarks request all tests and benchmarks, if they are provided. What is requested can be read off directly from ComponentRequestedSpec. A requested component is not always buildable; e.g., a user may --enable-tests but one of the test suites may have buildable: False.

A component is enabled if it is BOTH buildable and requested. Once we have a LocalBuildInfo, whether or not a component is enabled is known.

Generally speaking, most Cabal API code cares if a component is enabled. (For example, if you want to run a preprocessor on each component prior to building them, you want to run this on each enabled component.)

Note that post-configuration, you will generally not see a non-buildable Component. This is because flattenPD will drop any such components from PackageDescription. See #3858 for an example where this causes problems.

data ComponentRequestedSpec

Describes what components are enabled by user-interaction. See also this note in Distribution.Types.ComponentRequestedSpec.

Since: 2.0.0.2

Constructors

ComponentRequestedSpec

Fields

• testsRequested :: Bool
• benchmarksRequested :: Bool

OneComponentRequestedSpec ComponentName

Instances

Structured ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

Methods

structure :: Proxy ComponentRequestedSpec -> Structure

structureHash' :: Tagged ComponentRequestedSpec MD5

Generic ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

Associated Types

type Rep ComponentRequestedSpec :: Type -> Type

Methods

from :: ComponentRequestedSpec -> Rep ComponentRequestedSpec x

to :: Rep ComponentRequestedSpec x -> ComponentRequestedSpec

Read ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

Methods

readsPrec :: Int -> ReadS ComponentRequestedSpec

readList :: ReadS [ComponentRequestedSpec]

readPrec :: ReadPrec ComponentRequestedSpec

readListPrec :: ReadPrec [ComponentRequestedSpec]

Show ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

Methods

showsPrec :: Int -> ComponentRequestedSpec -> ShowS

show :: ComponentRequestedSpec -> String

showList :: [ComponentRequestedSpec] -> ShowS

Binary ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

Methods

put :: ComponentRequestedSpec -> Put

get :: Get ComponentRequestedSpec

putList :: [ComponentRequestedSpec] -> Put

Eq ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

Methods

(==) :: ComponentRequestedSpec -> ComponentRequestedSpec -> Bool

(/=) :: ComponentRequestedSpec -> ComponentRequestedSpec -> Bool

type Rep ComponentRequestedSpec

Defined in Distribution.Types.ComponentRequestedSpec

type Rep ComponentRequestedSpec = D1 ('MetaData "ComponentRequestedSpec" "Distribution.Types.ComponentRequestedSpec" "Cabal-syntax-3.10.2.0-4s9v55YS0UyD8dLofJ8HlN" 'False) (C1 ('MetaCons "ComponentRequestedSpec" 'PrefixI 'True) (S1 ('MetaSel ('Just "testsRequested") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Bool) :*: S1 ('MetaSel ('Just "benchmarksRequested") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Bool)) :+: C1 ('MetaCons "OneComponentRequestedSpec" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 ComponentName)))

data ComponentDisabledReason

A reason explaining why a component is disabled.

Since: 2.0.0.2

Constructors

DisabledComponent

DisabledAllTests

DisabledAllBenchmarks

DisabledAllButOne String

defaultComponentRequestedSpec :: ComponentRequestedSpec

The default set of enabled components. Historically tests and benchmarks are NOT enabled by default.

Since: 2.0.0.2

componentNameRequested :: ComponentRequestedSpec -> ComponentName -> Bool

Is this component name enabled? See also this note in Distribution.Types.ComponentRequestedSpec.

Since: 2.0.0.2

componentEnabled :: ComponentRequestedSpec -> Component -> Bool

Is this component enabled? See also this note in Distribution.Types.ComponentRequestedSpec.

Since: 2.0.0.2

componentDisabledReason :: ComponentRequestedSpec -> Component -> Maybe ComponentDisabledReason

Is this component disabled, and if so, why?

Since: 2.0.0.2