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Add cabal get --only-package-description (#8263)
With this option, 'cabal get' writes to the destination directory only the package description already available locally in one of the repository indices. The basename of the file name written to inside the target directory is the package-id rather than only the package name. This is mostly based on #1977 Co-authored-by: Miëtek Bak <[email protected]> Co-authored-by: Artem Pelenitsyn <[email protected]> Co-authored-by: Herbert Valerio Riedel <[email protected]> Co-authored-by: Miëtek Bak <[email protected]>
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‎cabal-install/src/Distribution/Client/Get.hs

Lines changed: 34 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -31,7 +31,7 @@ import Distribution.Package
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import Distribution.Simple.Setup
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( Flag(..), fromFlag, fromFlagOrDefault, flagToMaybe )
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import Distribution.Simple.Utils
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( notice, die', info, writeFileAtomic )
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( notice, die', info, warn, writeFileAtomic )
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import qualified Distribution.PackageDescription as PD
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import Distribution.Simple.Program
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( programName )
@@ -49,8 +49,11 @@ import qualified Distribution.Client.Tar as Tar (extractTarGzFile)
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import Distribution.Client.IndexUtils
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( getSourcePackagesAtIndexState, TotalIndexState, ActiveRepos )
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import Distribution.Solver.Types.SourcePackage
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import Distribution.PackageDescription.PrettyPrint
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( writeGenericPackageDescription )
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import qualified Data.Map as Map
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import Control.Monad ( mapM_ )
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import System.Directory
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( createDirectoryIfMissing, doesDirectoryExist, doesFileExist )
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import System.FilePath
@@ -94,16 +97,26 @@ get verbosity repoCtxt _ getFlags userTargets = do
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unless (null prefix) $
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createDirectoryIfMissing True prefix
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if useSourceRepo
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then clone pkgs
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else unpack pkgs
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if onlyPkgDescr
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then do
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when useSourceRepo $
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warn verbosity $
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"Ignoring --source-repository for --only-package-description"
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mapM_ (unpackOnlyPkgDescr verbosity prefix) pkgs
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else
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if useSourceRepo
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then clone pkgs
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else unpack pkgs
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where
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resolverParams :: SourcePackageDb -> [PackageSpecifier UnresolvedSourcePackage] -> DepResolverParams
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resolverParams sourcePkgDb pkgSpecifiers =
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--TODO: add command-line constraint and preference args for unpack
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standardInstallPolicy mempty sourcePkgDb pkgSpecifiers
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onlyPkgDescr = fromFlagOrDefault False (getOnlyPkgDescr getFlags)
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prefix :: String
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prefix = fromFlagOrDefault "" (getDestDir getFlags)
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@@ -189,6 +202,23 @@ unpackPackage verbosity prefix pkgid descOverride pkgPath = do
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writeFileAtomic descFilePath pkgtxt
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-- | Write a @pkgId.cabal@ file with the package description to the destination
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-- directory, unless one already exists.
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unpackOnlyPkgDescr :: Verbosity -> FilePath -> UnresolvedSourcePackage -> IO ()
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unpackOnlyPkgDescr verbosity dstDir pkg = do
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let pkgFile = dstDir </> prettyShow (packageId pkg) <.> "cabal"
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existsFile <- doesFileExist pkgFile
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when existsFile $ die' verbosity $
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"The file \"" ++ pkgFile ++ "\" already exists, not overwriting."
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existsDir <- doesDirectoryExist (addTrailingPathSeparator pkgFile)
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when existsDir $ die' verbosity $
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"A directory \"" ++ pkgFile ++ "\" is in the way, not unpacking."
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notice verbosity $ "Writing package description to " ++ pkgFile
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case srcpkgDescrOverride pkg of
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Just pkgTxt -> writeFileAtomic pkgFile pkgTxt
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Nothing ->
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writeGenericPackageDescription pkgFile (srcpkgDescription pkg)
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-- ------------------------------------------------------------
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-- * Cloning packages from their declared source repositories
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-- ------------------------------------------------------------

‎cabal-install/src/Distribution/Client/Setup.hs

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1297,6 +1297,7 @@ instance Semigroup ReportFlags where
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data GetFlags = GetFlags {
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getDestDir :: Flag FilePath,
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getOnlyPkgDescr :: Flag Bool,
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getPristine :: Flag Bool,
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getIndexState :: Flag TotalIndexState,
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getActiveRepos :: Flag ActiveRepos,
@@ -1307,6 +1308,7 @@ data GetFlags = GetFlags {
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defaultGetFlags :: GetFlags
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defaultGetFlags = GetFlags {
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getDestDir = mempty,
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getOnlyPkgDescr = mempty,
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getPristine = mempty,
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getIndexState = mempty,
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getActiveRepos = mempty,
@@ -1352,6 +1354,16 @@ getCommand = CommandUI {
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(toFlag `fmap` parsec))
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(flagToList . fmap prettyShow))
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, option [] ["only-package-description"]
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"Unpack only the package description file."
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getOnlyPkgDescr (\v flags -> flags { getOnlyPkgDescr = v })
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trueArg
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, option [] ["package-description-only"]
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"A synonym for --only-package-description."
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getOnlyPkgDescr (\v flags -> flags { getOnlyPkgDescr = v })
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trueArg
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, option [] ["pristine"]
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("Unpack the original pristine tarball, rather than updating the "
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++ ".cabal file with the latest revision from the package archive.")

‎cabal-testsuite/PackageTests/Get/OnlyDescription/cabal.out

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
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# cabal v2-update
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Downloading the latest package list from test-local-repo
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# cabal update
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Downloading the latest package list from test-local-repo
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# cabal get
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Writing package description to criterion-1.1.4.0.cabal

‎cabal-testsuite/PackageTests/Get/OnlyDescription/cabal.test.hs

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@@ -0,0 +1,11 @@
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-- 2022-07-03, issue #1954
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--
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-- Purpose of this test:
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-- Make sure that `cabal get --only-package-description` works
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import Test.Cabal.Prelude
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main = cabalTest $ withRepo "repo" $ do
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cabal "update" []
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cabal
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"get"
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[ "criterion", "--only-package-description" ]

‎cabal-testsuite/PackageTests/Get/OnlyDescription/repo/criterion-1.1.4.0/criterion.cabal

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@@ -0,0 +1,8 @@
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name: criterion
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version: 1.1.4.0
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build-type: Simple
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cabal-version: >= 1.10
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library
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build-depends: base, ghc-prim
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default-language: Haskell2010

‎changelog.d/issue-1954

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@@ -0,0 +1,4 @@
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synopsis: Add `cabal get --only-package-description`
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packages: cabal-install
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prs: #1977 #5162 #8263
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issues: #1954

‎changelog.d/issue-7462

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@@ -0,0 +1,4 @@
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synopsis: `cabal haddock` now implies `--enable-documentation`
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packages: Cabal
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issues: #1919
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prs: #7827

‎doc/cabal-package.rst

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Original file line numberDiff line numberDiff line change
@@ -2865,6 +2865,9 @@ The ``get`` command supports the following options:
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``2016-09-24T17:47:48Z``), or ``HEAD`` (default).
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This determines which package versions are available as well as which
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``.cabal`` file revision is selected (unless ``--pristine`` is used).
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``--only-package-description``
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Unpack only the package description file. A synonym,
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``--package-description-only``, is provided for convenience.
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``--pristine``
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Unpack the original pristine tarball, rather than updating the
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``.cabal`` file with the latest revision from the package archive.

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