Do not use shallow clones for source-repository-packages

Fixes #10605

Includes a regression test.

Author: 9999years

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

@@ -483,9 +483,6 @@ vcsGit =
         resetArgs tag = "reset" : verboseArg ++ ["--hard", tag, "--"]
         verboseArg = ["--quiet" | verbosity < Verbosity.normal]
 
-    -- Note: No --depth=1 for vcsCloneRepo since that is used for `cabal get -s`,
-    -- whereas `vcsSyncRepo` is used for source-repository-package where we do want shallow clones.
-
     vcsSyncRepos
       :: Verbosity
       -> ConfiguredProgram
@@ -535,44 +532,9 @@ vcsGit =
               (\e -> if isPermissionError e then removePathForcibly gitModulesDir else throw e)
           else removeDirectoryRecursive gitModulesDir
 
-      -- If we want a particular branch or tag, fetch it.
-      ref <- case srpBranch `mplus` srpTag of
-        Nothing -> pure "HEAD"
-        Just ref -> do
-          -- /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\
-          -- /!\            MULTIPLE HOURS HAVE BEEN LOST HERE!!             /!\
-          -- /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\ /!\
-          --
-          -- If you run `git fetch origin MY_TAG`, then the tag _will_ be
-          -- fetched, but no local ref (e.g. `refs/tags/MY_TAG`) will be
-          -- created.
-          --
-          -- This means that doing `git fetch origin MY_TAG && git reset --hard
-          -- MY_TAG` will fail with a message like `unknown revision MY_TAG`.
-          --
-          -- There are two ways around this:
-          --
-          -- 1. Provide a refmap explicitly:
-          --
-          --        git fetch --refmap="+refs/tags/*:refs/tags/*" origin MYTAG
-          --
-          --    This tells Git to create local tags matching remote tags. It's
-          --    not in the default refmap so you need to set it explicitly.
-          --    (You can also set it with `git config set --local
-          --    remote.origin.fetch ...`.)
-          --
-          -- 2. Use `FETCH_HEAD` directly: Git writes a `FETCH_HEAD` ref
-          --    containing the commit that was just fetched. This feels a bit
-          --    nasty but seems to work reliably, even if nothing was fetched.
-          --    (That is, deleting `FETCH_HEAD` and re-running a `git fetch`
-          --    command will succesfully recreate the `FETCH_HEAD` ref.)
-          --
-          -- Option 2 is what Cabal has done historically, and we're keeping it
-          -- for now. Option 1 is possible but seems to have little benefit.
-          git localDir ("fetch" : verboseArg ++ ["origin", ref])
-          pure "FETCH_HEAD"
-
-      -- Then, reset to the appropriate ref.
+      -- If we want a particular branch or tag, reset to it.
+      -- Otherwise, check out the default `HEAD`.
+      let ref = fromMaybe "HEAD" $ srpBranch `mplus` srpTag
       git localDir $
         "reset"
           : verboseArg
@@ -594,7 +556,7 @@ vcsGit =
               }
 
         cloneArgs =
-          ["clone", "--depth=1", "--no-checkout", loc, localDir]
+          ["clone", "--no-checkout", loc, localDir]
             ++ case peer of
               Nothing -> []
               Just peerLocalDir -> ["--reference", peerLocalDir]

cabal-testsuite/PackageTests/SourceRepositoryPackageShallow/cabal.out

@@ -0,0 +1,10 @@
+# cabal v2-build
+Configuration is affected by the following files:
+- cabal.project
+Resolving dependencies...
+Build profile: -w ghc-<GHCVER> -O1
+In order, the following will be built:
+ - puppy-1.0 (lib) (first run)
+Configuring library for puppy-1.0...
+Preprocessing library for puppy-1.0...
+Building library for puppy-1.0...

cabal-testsuite/PackageTests/SourceRepositoryPackageShallow/cabal.project

@@ -0,0 +1,8 @@
+packages: .
+
+-- Regression for https://github.com/haskell/cabal/issues/10605
+source-repository-package
+    type: git
+    location: https://github.com/haskell/bytestring
+    -- Uses an abbreviated commit hash (not a tag! why was this ever accepted???)
+    tag: c73756a

cabal-testsuite/PackageTests/SourceRepositoryPackageShallow/cabal.test.hs

@@ -0,0 +1,4 @@
+import Test.Cabal.Prelude
+
+main = cabalTest $ do
+  cabal "v2-build" []

cabal-testsuite/PackageTests/SourceRepositoryPackageShallow/puppy.cabal

@@ -0,0 +1,9 @@
+cabal-version:      3.0
+name:               puppy
+version:            1.0
+
+library
+    default-language: Haskell2010
+    hs-source-dirs:   src
+    build-depends:    base
+    exposed-modules:  Puppy

cabal-testsuite/PackageTests/SourceRepositoryPackageShallow/src/Puppy.hs

@@ -0,0 +1 @@
+module Puppy () where