ghc-8.8.1: The GHC API
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Package manipulation



Reading the package config, and processing cmdline args

data PackageConfigMap Source #

UniqFM map from UnitId to PackageConfig, plus the transitive closure of preload packages.

initPackages :: DynFlags -> IO (DynFlags, [PreloadUnitId]) Source #

Call this after parseDynFlags. It reads the package database files, and sets up various internal tables of package information, according to the package-related flags on the command-line (-package, -hide-package etc.)

Returns a list of packages to link in if we're doing dynamic linking. This list contains the packages that the user explicitly mentioned with -package flags.

initPackages can be called again subsequently after updating the packageFlags field of the DynFlags, and it will update the pkgState in DynFlags and return a list of packages to link in.

listPackageConfigMap :: DynFlags -> [PackageConfig] Source #

Get a list of entries from the package database. NB: be careful with this function, although all packages in this map are "visible", this does not imply that the exposed-modules of the package are available (they may have been thinned or renamed).

Querying the package config

lookupPackage :: DynFlags -> UnitId -> Maybe PackageConfig Source #

Find the package we know about with the given unit id, if any

lookupPackage' :: Bool -> PackageConfigMap -> UnitId -> Maybe PackageConfig Source #

A more specialized interface, which takes a boolean specifying whether or not to look for on-the-fly renamed interfaces, and just a PackageConfigMap rather than a DynFlags (so it can be used while we're initializing DynFlags

lookupPackageName :: DynFlags -> PackageName -> Maybe ComponentId Source #

Find the package we know about with the given package name (e.g. foo), if any (NB: there might be a locally defined unit name which overrides this)

improveUnitId :: PackageConfigMap -> UnitId -> UnitId Source #

Given a fully instantiated UnitId, improve it into a InstalledUnitId if we can find it in the package database.

searchPackageId :: DynFlags -> SourcePackageId -> [PackageConfig] Source #

Search for packages with a given package ID (e.g. "foo-0.1")

getPackageDetails :: DynFlags -> UnitId -> PackageConfig Source #

Looks up the package with the given id in the package state, panicing if it is not found

lookupModuleInAllPackages :: DynFlags -> ModuleName -> [(Module, PackageConfig)] Source #

Takes a ModuleName, and if the module is in any package returns list of modules which take that name.

data LookupResult Source #

The result of performing a lookup


LookupFound Module PackageConfig

Found the module uniquely, nothing else to do

LookupMultiple [(Module, ModuleOrigin)]

Multiple modules with the same name in scope

LookupHidden [(Module, ModuleOrigin)] [(Module, ModuleOrigin)]

No modules found, but there were some hidden ones with an exact name match. First is due to package hidden, second is due to module being hidden

LookupUnusable [(Module, ModuleOrigin)]

No modules found, but there were some unusable ones with an exact name match

LookupNotFound [ModuleSuggestion]

Nothing found, here are some suggested different names

data ModuleOrigin Source #

Package state is all stored in DynFlags, including the details of all packages, which packages are exposed, and which modules they provide.

The package state is computed by initPackages, and kept in DynFlags. It is influenced by various package flags:

  • -package pkg and -package-id pkg cause pkg to become exposed. If -hide-all-packages was not specified, these commands also cause all other packages with the same name to become hidden.
  • -hide-package pkg causes pkg to become hidden.
  • (there are a few more flags, check below for their semantics)

The package state has the following properties.

  • Let exposedPackages be the set of packages thus exposed. Let depExposedPackages be the transitive closure from exposedPackages of their dependencies.
  • When searching for a module from a preload import declaration, only the exposed modules in exposedPackages are valid.
  • When searching for a module from an implicit import, all modules from depExposedPackages are valid.
  • When linking in a compilation manager mode, we link in packages the program depends on (the compiler knows this list by the time it gets to the link step). Also, we link in all packages which were mentioned with preload -package flags on the command-line, or are a transitive dependency of same, or are "base"/"rts". The reason for this is that we might need packages which don't contain any Haskell modules, and therefore won't be discovered by the normal mechanism of dependency tracking.

Given a module name, there may be multiple ways it came into scope, possibly simultaneously. This data type tracks all the possible ways it could have come into scope. Warning: don't use the record functions, they're partial!



Module is hidden, and thus never will be available for import. (But maybe the user didn't realize), so we'll still keep track of these modules.)

ModUnusable UnusablePackageReason

Module is unavailable because the package is unusable.


Module is public, and could have come from some places.


data UnusablePackageReason Source #

The reason why a package is unusable.



We ignored it explicitly using -ignore-package.

BrokenDependencies [InstalledUnitId]

This package transitively depends on a package that was never present in any of the provided databases.

CyclicDependencies [InstalledUnitId]

This package transitively depends on a package involved in a cycle. Note that the list of InstalledUnitId reports the direct dependencies of this package that (transitively) depended on the cycle, and not the actual cycle itself (which we report separately at high verbosity.)

IgnoredDependencies [InstalledUnitId]

This package transitively depends on a package which was ignored.

ShadowedDependencies [InstalledUnitId]

This package transitively depends on a package which was shadowed by an ABI-incompatible package.


Instances details
Outputable UnusablePackageReason Source # 
Instance details

Defined in Packages

Inspecting the set of packages in scope

getPackageIncludePath :: DynFlags -> [PreloadUnitId] -> IO [String] Source #

Find all the include directories in these and the preload packages

getPackageLibraryPath :: DynFlags -> [PreloadUnitId] -> IO [String] Source #

Find all the library paths in these and the preload packages

getPackageLinkOpts :: DynFlags -> [PreloadUnitId] -> IO ([String], [String], [String]) Source #

Find all the link options in these and the preload packages, returning (package hs lib options, extra library options, other flags)

getPackageExtraCcOpts :: DynFlags -> [PreloadUnitId] -> IO [String] Source #

Find all the C-compiler options in these and the preload packages

getPackageFrameworkPath :: DynFlags -> [PreloadUnitId] -> IO [String] Source #

Find all the package framework paths in these and the preload packages

getPackageFrameworks :: DynFlags -> [PreloadUnitId] -> IO [String] Source #

Find all the package frameworks in these and the preload packages

getPackageConfigMap :: DynFlags -> PackageConfigMap Source #

Retrieve the PackageConfigMap from DynFlags; used in the hs-boot loop-breaker.

getPreloadPackagesAnd :: DynFlags -> [PreloadUnitId] -> IO [PackageConfig] Source #

Find all the PackageConfig in both the preload packages from DynFlags and corresponding to the list of PackageConfigs

getLibs :: DynFlags -> [PreloadUnitId] -> IO [(String, String)] Source #


unwireUnitId :: DynFlags -> UnitId -> UnitId Source #

Given a wired-in UnitId, "unwire" it into the UnitId that it was recorded as in the package database.

pprPackages :: DynFlags -> SDoc Source #

Show (very verbose) package info

pprPackagesSimple :: DynFlags -> SDoc Source #

Show simplified package info.

The idea is to only print package id, and any information that might be different from the package databases (exposure, trust)

pprModuleMap :: ModuleToPkgConfAll -> SDoc Source #

Show the mapping of modules to where they come from.

isIndefinite :: DynFlags -> Bool Source #

A little utility to tell if the thisPackage is indefinite (if it is not, we should never use on-the-fly renaming.)

isDllName :: DynFlags -> Module -> Name -> Bool Source #

Will the Name come from a dynamically linked library?