diff --git a/Cabal/src/Distribution/Compat/Prelude.hs b/Cabal/src/Distribution/Compat/Prelude.hs
index edc7eb3386e..4eb6528e002 100644
--- a/Cabal/src/Distribution/Compat/Prelude.hs
+++ b/Cabal/src/Distribution/Compat/Prelude.hs
@@ -71,7 +71,7 @@ module Distribution.Compat.Prelude (
     partition,
 
     -- * Data.List.NonEmpty
-    NonEmpty((:|)), foldl1, foldr1,
+    NonEmpty((:|)), nonEmpty, foldl1, foldr1,
     head, tail, last, init,
 
     -- * Data.Foldable
@@ -187,7 +187,7 @@ import Data.Function                 (on)
 import Data.Functor.Identity         (Identity (..))
 import Data.Int                      (Int16, Int32, Int64, Int8)
 import Data.List                     (intercalate, intersperse, isPrefixOf, isSuffixOf, nub, nubBy, partition, sort, sortBy, unfoldr)
-import Data.List.NonEmpty            (NonEmpty ((:|)), head, init, last, tail)
+import Data.List.NonEmpty            (NonEmpty ((:|)), nonEmpty, head, init, last, tail)
 import Data.Map                      (Map)
 import Data.Maybe                    (catMaybes, fromMaybe, isJust, isNothing, listToMaybe, mapMaybe, maybeToList)
 import Data.Ord                      (comparing)
diff --git a/Cabal/src/Distribution/Simple/Configure.hs b/Cabal/src/Distribution/Simple/Configure.hs
index e52c5b0d534..28e65a687ae 100644
--- a/Cabal/src/Distribution/Simple/Configure.hs
+++ b/Cabal/src/Distribution/Simple/Configure.hs
@@ -103,7 +103,6 @@ import qualified Distribution.Simple.HaskellSuite as HaskellSuite
 
 import Control.Exception
     ( try )
-import Data.List.NonEmpty            ( nonEmpty )
 import Distribution.Utils.Structured ( structuredDecodeOrFailIO, structuredEncode )
 import Distribution.Compat.Directory ( listDirectory )
 import Data.ByteString.Lazy          ( ByteString )
diff --git a/Cabal/src/Distribution/Simple/SrcDist.hs b/Cabal/src/Distribution/Simple/SrcDist.hs
index 10a9c8727f0..36ba5bd2488 100644
--- a/Cabal/src/Distribution/Simple/SrcDist.hs
+++ b/Cabal/src/Distribution/Simple/SrcDist.hs
@@ -450,7 +450,7 @@ allSourcesBuildInfo verbosity rip cwd bi pps modules = do
       -- file may show up in multiple paths due to a conditional;
       -- we need to package all of them.  See #367.
       in findAllFilesCwdWithExtension cwd suffixes searchDirs file
-         >>= nonEmpty (notFound module_) return
+         >>= nonEmpty' (notFound module_) return
     | module_ <- modules ++ otherModules bi ]
   bootFiles <- sequenceA
     [ let file = ModuleName.toFilePath module_
@@ -462,8 +462,10 @@ allSourcesBuildInfo verbosity rip cwd bi pps modules = do
            cmmSources bi ++ asmSources bi ++ jsSources bi
 
   where
-    nonEmpty x _ [] = x
-    nonEmpty _ f xs = f xs
+    nonEmpty' :: b -> ([a] -> b) -> [a] -> b
+    nonEmpty' x _ [] = x
+    nonEmpty' _ f xs = f xs
+
     suffixes = ppSuffixes pps ++ ["hs", "lhs", "hsig", "lhsig"]
 
     notFound :: ModuleName -> IO [FilePath]
diff --git a/Cabal/src/Distribution/Types/VersionInterval.hs b/Cabal/src/Distribution/Types/VersionInterval.hs
index 05354105d24..d07a47f3fd0 100644
--- a/Cabal/src/Distribution/Types/VersionInterval.hs
+++ b/Cabal/src/Distribution/Types/VersionInterval.hs
@@ -142,7 +142,7 @@ insertInterval :: VersionInterval -> VersionIntervals -> VersionIntervals
 insertInterval i is = unionVersionIntervals (VersionIntervals [i]) is
 
 validInterval :: (LowerBound, UpperBound) -> Bool
-validInterval i@(l, u) = validLower l && validUpper u && nonEmpty i
+validInterval i@(l, u) = validLower l && validUpper u && nonEmptyVI i
   where
     validLower (LowerBound v _) = validVersion v
     validUpper NoUpperBound     = True
@@ -150,9 +150,9 @@ validInterval i@(l, u) = validLower l && validUpper u && nonEmpty i
 
 -- Check an interval is non-empty
 --
-nonEmpty :: VersionInterval -> Bool
-nonEmpty (_,               NoUpperBound   ) = True
-nonEmpty (LowerBound l lb, UpperBound u ub) =
+nonEmptyVI :: VersionInterval -> Bool
+nonEmptyVI (_,               NoUpperBound   ) = True
+nonEmptyVI (LowerBound l lb, UpperBound u ub) =
   (l < u) || (l == u && lb == InclusiveBound && ub == InclusiveBound)
 
 -- Check an upper bound does not intersect, or even touch a lower bound:
diff --git a/cabal-install/src/Distribution/Client/List.hs b/cabal-install/src/Distribution/Client/List.hs
index fd792b6845d..97fdb51aaf8 100644
--- a/cabal-install/src/Distribution/Client/List.hs
+++ b/cabal-install/src/Distribution/Client/List.hs
@@ -67,7 +67,7 @@ import Distribution.Client.FetchUtils
 import Data.Bits ((.|.))
 import Data.List
          ( maximumBy )
-import Data.List.NonEmpty (groupBy, nonEmpty)
+import Data.List.NonEmpty (groupBy)
 import qualified Data.List as L
 import Data.Maybe
          ( fromJust )
diff --git a/cabal-install/src/Distribution/Client/ProjectConfig.hs b/cabal-install/src/Distribution/Client/ProjectConfig.hs
index 5c8cf444ca7..5a42729a841 100644
--- a/cabal-install/src/Distribution/Client/ProjectConfig.hs
+++ b/cabal-install/src/Distribution/Client/ProjectConfig.hs
@@ -116,7 +116,7 @@ import Distribution.Simple.InstallDirs
          ( PathTemplate, fromPathTemplate
          , toPathTemplate, substPathTemplate, initialPathTemplateEnv )
 import Distribution.Simple.Utils
-         ( die', warn, notice, info, createDirectoryIfMissingVerbose )
+         ( die', warn, notice, info, createDirectoryIfMissingVerbose, rawSystemIOWithEnv )
 import Distribution.Client.Utils
          ( determineNumJobs )
 import Distribution.Utils.NubList
@@ -1172,7 +1172,12 @@ syncAndReadSourcePackagesRemoteRepos verbosity
         syncSourceRepos verbosity vcs
           [ (repo, repoPath)
           | (repo, _, repoPath) <- repoGroupWithPaths ]
-        -- TODO phadej 2020-06-18 add post-sync script
+
+        -- Run post-checkout-command if it is specified
+        for_ repoGroupWithPaths $ \(repo, _, repoPath) ->
+            for_ (nonEmpty (srpCommand repo)) $ \(cmd :| args) -> liftIO $ do
+                exitCode <- rawSystemIOWithEnv verbosity cmd args (Just repoPath) Nothing Nothing Nothing Nothing
+                unless (exitCode /= ExitSuccess) $ exitWith exitCode
 
         -- But for reading we go through each 'SourceRepo' including its subdir
         -- value and have to know which path each one ended up in.
diff --git a/cabal-install/src/Distribution/Client/ProjectConfig/Legacy.hs b/cabal-install/src/Distribution/Client/ProjectConfig/Legacy.hs
index 39a0342aa08..c7622c092e0 100644
--- a/cabal-install/src/Distribution/Client/ProjectConfig/Legacy.hs
+++ b/cabal-install/src/Distribution/Client/ProjectConfig/Legacy.hs
@@ -1224,7 +1224,9 @@ legacyPackageConfigFieldDescrs =
 
 legacyPackageConfigFGSectionDescrs
     :: ( FieldGrammar c g, Applicative (g SourceRepoList)
-       , c (Identity RepoType), c (List NoCommaFSep FilePathNT String)
+       , c (Identity RepoType)
+       , c (List NoCommaFSep FilePathNT String)
+       , c (NonEmpty' NoCommaFSep Token String)
        )
     => [FGSectionDescr g LegacyProjectConfig]
 legacyPackageConfigFGSectionDescrs =
@@ -1253,7 +1255,9 @@ legacyPackageConfigSectionDescrs =
 
 packageRepoSectionDescr
     :: ( FieldGrammar c g, Applicative (g SourceRepoList)
-       , c (Identity RepoType), c (List NoCommaFSep FilePathNT String)
+       , c (Identity RepoType)
+       , c (List NoCommaFSep FilePathNT String)
+       , c (NonEmpty' NoCommaFSep Token String)
        )
     => FGSectionDescr g LegacyProjectConfig
 packageRepoSectionDescr = FGSectionDescr
diff --git a/cabal-install/src/Distribution/Client/Types/SourceRepo.hs b/cabal-install/src/Distribution/Client/Types/SourceRepo.hs
index 0cc44ff7472..751c6c97266 100644
--- a/cabal-install/src/Distribution/Client/Types/SourceRepo.hs
+++ b/cabal-install/src/Distribution/Client/Types/SourceRepo.hs
@@ -32,6 +32,7 @@ data SourceRepositoryPackage f = SourceRepositoryPackage
     , srpTag      :: !(Maybe String)
     , srpBranch   :: !(Maybe String)
     , srpSubdir   :: !(f FilePath)
+    , srpCommand  :: ![String]
     }
   deriving (Generic)
 
@@ -88,6 +89,10 @@ srpSubdirLens :: Lens (SourceRepositoryPackage f) (SourceRepositoryPackage g) (f
 srpSubdirLens f s = fmap (\x -> s { srpSubdir = x }) (f (srpSubdir s))
 {-# INLINE srpSubdirLens #-}
 
+srpCommandLensNE :: Lens' (SourceRepositoryPackage f) (Maybe (NonEmpty String))
+srpCommandLensNE f s = fmap (\x -> s { srpCommand = maybe [] toList x }) (f (nonEmpty (srpCommand s)))
+{-# INLINE srpCommandLensNE #-}
+
 -------------------------------------------------------------------------------
 -- Parser & PPrinter
 -------------------------------------------------------------------------------
@@ -96,6 +101,7 @@ sourceRepositoryPackageGrammar
     :: ( FieldGrammar c g, Applicative (g SourceRepoList)
        , c (Identity RepoType)
        , c (List NoCommaFSep FilePathNT String)
+       , c (NonEmpty' NoCommaFSep Token String)
        )
     => g SourceRepoList SourceRepoList
 sourceRepositoryPackageGrammar = SourceRepositoryPackage
@@ -104,5 +110,8 @@ sourceRepositoryPackageGrammar = SourceRepositoryPackage
     <*> optionalFieldAla "tag"      Token                             srpTagLens
     <*> optionalFieldAla "branch"   Token                             srpBranchLens
     <*> monoidalFieldAla "subdir"   (alaList' NoCommaFSep FilePathNT) srpSubdirLens  -- note: NoCommaFSep is somewhat important for roundtrip, as "." is there...
+    <*> fmap (maybe [] toList) pcc
+  where
+    pcc = optionalFieldAla "post-checkout-command" (alaNonEmpty' NoCommaFSep Token) srpCommandLensNE
 {-# SPECIALIZE sourceRepositoryPackageGrammar :: ParsecFieldGrammar' SourceRepoList #-}
 {-# SPECIALIZE sourceRepositoryPackageGrammar :: PrettyFieldGrammar' SourceRepoList #-}
diff --git a/cabal-install/src/Distribution/Client/VCS.hs b/cabal-install/src/Distribution/Client/VCS.hs
index 49addef110c..2f2fd9fa41c 100644
--- a/cabal-install/src/Distribution/Client/VCS.hs
+++ b/cabal-install/src/Distribution/Client/VCS.hs
@@ -127,6 +127,7 @@ validatePDSourceRepo repo = do
         , srpTag      = PD.repoTag repo
         , srpBranch   = PD.repoBranch repo
         , srpSubdir   = PD.repoSubdir repo
+        , srpCommand  = mempty
         }
   where
     a ?! e = maybe (Left e) Right a
diff --git a/cabal-install/tests/UnitTests/Distribution/Client/Get.hs b/cabal-install/tests/UnitTests/Distribution/Client/Get.hs
index aa4378ede7e..313eccc6955 100644
--- a/cabal-install/tests/UnitTests/Distribution/Client/Get.hs
+++ b/cabal-install/tests/UnitTests/Distribution/Client/Get.hs
@@ -106,6 +106,7 @@ testUnsupportedRepoType = do
                , srpTag      = Nothing
                , srpBranch   = Nothing
                , srpSubdir   = Proxy
+               , srpCommand  = []
                }
     repotype = OtherRepoType "baz"
 
@@ -184,6 +185,7 @@ testGitFetchFailed =
                      , srpTag      = Nothing
                      , srpBranch   = Nothing
                      , srpSubdir   = Proxy
+                     , srpCommand  = []
                      }
           pkgrepos = [(pkgidfoo, [repo])]
       e1 <- assertException $
diff --git a/cabal-install/tests/UnitTests/Distribution/Client/ProjectConfig.hs b/cabal-install/tests/UnitTests/Distribution/Client/ProjectConfig.hs
index 7be686771e8..132aa4090d8 100644
--- a/cabal-install/tests/UnitTests/Distribution/Client/ProjectConfig.hs
+++ b/cabal-install/tests/UnitTests/Distribution/Client/ProjectConfig.hs
@@ -735,17 +735,15 @@ instance f ~ [] => Arbitrary (SourceRepositoryPackage f) where
         <*> (fmap getShortToken <$> arbitrary)
         <*> (fmap getShortToken <$> arbitrary)
         <*> (fmap getShortToken <$> shortListOf 3 arbitrary)
+        <*> (fmap getShortToken <$> shortListOf 3 arbitrary)
 
-    shrink (SourceRepositoryPackage x1 x2 x3 x4 x5) =
-        [ SourceRepositoryPackage
-            x1'
-            (getShortToken x2')
-            (fmap getShortToken x3')
-            (fmap getShortToken x4')
-            (fmap getShortToken x5')
-        | (x1', x2', x3', x4', x5') <- shrink
-          (x1, ShortToken x2, fmap ShortToken x3, fmap ShortToken x4, fmap ShortToken x5)
-        ]
+    shrink SourceRepositoryPackage {..} = runShrinker $ pure SourceRepositoryPackage
+        <*> shrinker srpType
+        <*> shrinkerAla ShortToken srpLocation
+        <*> shrinkerAla (fmap ShortToken) srpTag
+        <*> shrinkerAla (fmap ShortToken) srpBranch
+        <*> shrinkerAla (fmap ShortToken) srpSubdir
+        <*> shrinkerAla (fmap ShortToken) srpCommand
 
 instance Arbitrary RemoteRepo where
     arbitrary =
diff --git a/cabal-install/tests/UnitTests/Distribution/Client/VCS.hs b/cabal-install/tests/UnitTests/Distribution/Client/VCS.hs
index 2cf222b0a75..e4d68b0f5ac 100644
--- a/cabal-install/tests/UnitTests/Distribution/Client/VCS.hs
+++ b/cabal-install/tests/UnitTests/Distribution/Client/VCS.hs
@@ -215,6 +215,7 @@ prop_cloneRepo vcs mkVCSTestDriver repoRecipe =
             , srpTag      = Just tagname
             , srpBranch   = Nothing
             , srpSubdir   = []
+            , srpCommand  = []
             }
     verbosity = silent
 
@@ -315,6 +316,7 @@ pickSyncTargetSets repoType repoState srcRepoPath dstReposPath =
                               , srpTag      = Just tag
                               , srpBranch   = Nothing
                               , srpSubdir   = Proxy
+                              , srpCommand  = []
                               }
         (tag, workingState) = Map.elemAt tagIdx (allTags repoState)
         (tagIdx, prng')     = randomR (0, Map.size (allTags repoState) - 1) prng
diff --git a/changelog.d/documentation b/changelog.d/documentation
index b6541b309b9..4eda812ed60 100644
--- a/changelog.d/documentation
+++ b/changelog.d/documentation
@@ -1,5 +1,6 @@
 synopsis: Documentation improvements
-prs: #6971
+prs: #6971 #7047
+issues: #6813
 
 description: {
 
diff --git a/changelog.d/issue-6664-pre-sdist-command b/changelog.d/issue-6664-pre-sdist-command
new file mode 100644
index 00000000000..2b513d1374a
--- /dev/null
+++ b/changelog.d/issue-6664-pre-sdist-command
@@ -0,0 +1,3 @@
+synopsis: Add post-checkout-command to source-package-repository
+issues: #6664
+prs: #7047
diff --git a/doc/cabal-project.rst b/doc/cabal-project.rst
index c3e1430c539..aea61583477 100644
--- a/doc/cabal-project.rst
+++ b/doc/cabal-project.rst
@@ -147,14 +147,7 @@ Specifying Packages from Remote Version Control Locations
 
 Starting with Cabal 2.4, there is now a stanza
 ``source-repository-package`` for specifying packages from an external
-version control which supports the following fields:
-
-- :pkg-field:`source-repository:type`
-- :pkg-field:`source-repository:location`
-- :pkg-field:`source-repository:tag`
-- :pkg-field:`source-repository:subdir`
-
-A simple example is shown below:
+version control.
 
 .. code-block:: cabal
 
@@ -171,6 +164,29 @@ A simple example is shown below:
         tag: 3d274c14ca3077c3a081ba7ad57c5182da65c8c1
         subdir: cborg
 
+    source-repository-package
+        type: git
+        location: https://github.com/haskell/network.git
+        tag: e76fdc753e660dfa615af6c8b6a2ad9ddf6afe70
+        post-checkout-command: autoreconf -i
+
+cabal-install 3.4 sdists the ``source-repository-package`` repositories and uses resulting tarballs as project packages.
+This allows sharing of packages across different projects.
+
+.. cfg-field:: type: VCS kind
+
+.. cfg-field:: location: VCS location (usually URL)
+
+.. cfg-field:: type: VCS tag
+
+.. cfg-field:: subdir: subdirectory list
+
+    Use one or more subdirectories of the repository.
+
+.. cfg-field:: post-checkout-command: command
+
+    Run command in the checked out repository, prior sdisting.
+
 Global configuration options
 ----------------------------