Stop using ref in builtins.fetchGit fetcher

Instead, sources now record either `branch` or `tag`. The fetcher
specifies the correct ref (`/refs/heads/...` or `/refs/tags/...`) which
works in the newest version of Nix. The `ref` attribute can still be set
to override the logic.

nix/sources.nix

@@ -24,8 +24,15 @@ let
       else
         pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
 
-  fetch_git = spec:
-    builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
+  fetch_git = name: spec:
+    let
+      ref =
+        if spec ? ref then spec.ref else
+          if spec ? branch then "refs/heads/${spec.branch}" else
+            if spec ? tag then "refs/tags/${spec.tag}" else
+              abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
+    in
+      builtins.fetchGit { url = spec.repo; inherit (spec) rev; inherit ref; };
 
   fetch_local = spec: spec.path;
 
@@ -77,7 +84,7 @@ let
       abort "ERROR: niv spec ${name} does not have a 'type' attribute"
     else if spec.type == "file" then fetch_file pkgs name spec
     else if spec.type == "tarball" then fetch_tarball pkgs name spec
-    else if spec.type == "git" then fetch_git spec
+    else if spec.type == "git" then fetch_git name spec
     else if spec.type == "local" then fetch_local spec
     else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
     else if spec.type == "builtin-url" then fetch_builtin-url name

src/Niv/Git/Cmd.hs

@@ -53,7 +53,7 @@ parseGitShortcut txt'@(T.dropWhileEnd (== '/') -> txt) =
 parseGitPackageSpec :: Opts.Parser PackageSpec
 parseGitPackageSpec =
   (PackageSpec . HMS.fromList)
-    <$> many (parseRepo <|> parseRef <|> parseRev <|> parseAttr <|> parseSAttr)
+    <$> many (parseRepo <|> parseBranch <|> parseRev <|> parseAttr <|> parseSAttr)
   where
     parseRepo =
       ("repo",) . Aeson.String
@@ -67,11 +67,11 @@ parseGitPackageSpec =
           ( Opts.long "rev"
               <> Opts.metavar "SHA"
           )
-    parseRef =
-      ("ref",) . Aeson.String
+    parseBranch =
+      ("branch",) . Aeson.String
         <$> Opts.strOption
-          ( Opts.long "ref"
-              <> Opts.metavar "REF"
+          ( Opts.long "branch"
+              <> Opts.metavar "BRANCH"
           )
     parseAttr =
       Opts.option
@@ -112,7 +112,7 @@ describeGit =
           Opts.<$$> "  niv add git git@github.com:stedolan/jq"
           Opts.<$$> "  niv add git ssh://git@github.com/stedolan/jq --rev deadb33f"
           Opts.<$$> "  niv add git https://github.com/stedolan/jq.git"
-          Opts.<$$> "  niv add git --repo /my/custom/repo --name custom --ref foobar"
+          Opts.<$$> "  niv add git --repo /my/custom/repo --name custom --branch development"
     ]
 
 gitUpdate ::
@@ -121,34 +121,34 @@ gitUpdate ::
   -- | latest rev and default ref
   (T.Text -> IO (T.Text, T.Text)) ->
   Update () ()
-gitUpdate latestRev' defaultRefAndHEAD' = proc () -> do
+gitUpdate latestRev' defaultBranchAndRev' = proc () -> do
   useOrSet "type" -< ("git" :: Box T.Text)
   repository <- load "repo" -< ()
   discoverRev <+> discoverRefAndRev -< repository
   where
     discoverRefAndRev = proc repository -> do
-      refAndRev <- run defaultRefAndHEAD' -< repository
-      update "ref" -< fst <$> refAndRev
-      update "rev" -< snd <$> refAndRev
+      branchAndRev <- run defaultBranchAndRev' -< repository
+      update "branch" -< fst <$> branchAndRev
+      update "rev" -< snd <$> branchAndRev
       returnA -< ()
     discoverRev = proc repository -> do
-      ref <- load "ref" -< ()
-      rev <- run' (uncurry latestRev') -< (,) <$> repository <*> ref
+      branch <- load "branch" -< ()
+      rev <- run' (uncurry latestRev') -< (,) <$> repository <*> branch
       update "rev" -< rev
       returnA -< ()
 
 -- | The "real" (IO) update
 gitUpdate' :: Update () ()
-gitUpdate' = gitUpdate latestRev defaultRefAndHEAD
+gitUpdate' = gitUpdate latestRev defaultBranchAndRev
 
 latestRev ::
   -- | the repository
   T.Text ->
-  -- | the ref/branch
+  -- | the branch
   T.Text ->
   IO T.Text
-latestRev repo ref = do
-  let gitArgs = ["ls-remote", repo, "refs/heads/" <> ref]
+latestRev repo branch = do
+  let gitArgs = ["ls-remote", repo, "refs/heads/" <> branch]
   sout <- runGit gitArgs
   case sout of
     ls@(_ : _ : _) -> abortTooMuchOutput gitArgs ls
@@ -166,14 +166,14 @@ latestRev repo ref = do
       abortGitFailure args $ T.unlines $
         ["Git produced too much output:"] <> map ("  " <>) ls
 
-defaultRefAndHEAD ::
+defaultBranchAndRev ::
   -- | the repository
   T.Text ->
   IO (T.Text, T.Text)
-defaultRefAndHEAD repo = do
+defaultBranchAndRev repo = do
   sout <- runGit args
   case sout of
-    (l1 : l2 : _) -> (,) <$> parseRef l1 <*> parseRev l2
+    (l1 : l2 : _) -> (,) <$> parseBranch l1 <*> parseRev l2
     _ ->
       abortGitFailure args $ T.unlines $
         [ "Could not read reference and revision from stdout:"
@@ -181,11 +181,11 @@ defaultRefAndHEAD repo = do
           <> sout
   where
     args = ["ls-remote", "--symref", repo, "HEAD"]
-    parseRef l = maybe (abortNoRef args l) pure $ do
+    parseBranch l = maybe (abortNoRef args l) pure $ do
       -- ref: refs/head/master\tHEAD -> master\tHEAD
       refAndSym <- T.stripPrefix "ref: refs/heads/" l
-      let ref = T.takeWhile (/= '\t') refAndSym
-      if T.null ref then Nothing else Just ref
+      let branch = T.takeWhile (/= '\t') refAndSym
+      if T.null branch then Nothing else Just branch
     parseRev l = maybe (abortNoRev args l) pure $ do
       checkRev $ T.takeWhile (/= '\t') l
     checkRev t = if isRev t then Just t else Nothing

src/Niv/Git/Test.hs

@@ -57,7 +57,7 @@ test_gitUpdates =
 test_gitUpdateRev :: IO ()
 test_gitUpdateRev = do
   interState <- evalUpdate initialState $ proc () ->
-    gitUpdate (error "should be def") defaultRefAndHEAD' -< ()
+    gitUpdate (error "should be def") defaultBranchAndHEAD' -< ()
   let interState' = HMS.map (first (\_ -> Free)) interState
   actualState <- evalUpdate interState' $ proc () ->
     gitUpdate latestRev' (error "should update") -< ()
@@ -66,14 +66,14 @@ test_gitUpdateRev = do
     $ "State mismatch: " <> show actualState
   where
     latestRev' _ _ = pure "some-other-rev"
-    defaultRefAndHEAD' _ = pure ("some-ref", "some-rev")
+    defaultBranchAndHEAD' _ = pure ("some-branch", "some-rev")
     initialState =
       HMS.fromList
         [("repo", (Free, "git@github.com:nmattia/niv"))]
     expectedState =
       HMS.fromList
         [ ("repo", "git@github.com:nmattia/niv"),
-          ("ref", "some-ref"),
+          ("branch", "some-branch"),
           ("rev", "some-other-rev"),
           ("type", "git")
         ]
@@ -104,10 +104,10 @@ once2 f = do
 -- the update
 test_gitCalledOnce :: IO ()
 test_gitCalledOnce = do
-  defaultRefAndHEAD'' <- once1 defaultRefAndHEAD'
+  defaultBranchAndHEAD'' <- once1 defaultBranchAndHEAD'
   latestRev'' <- once2 latestRev'
   interState <- evalUpdate initialState $ proc () ->
-    gitUpdate (error "should be def") defaultRefAndHEAD'' -< ()
+    gitUpdate (error "should be def") defaultBranchAndHEAD'' -< ()
   let interState' = HMS.map (first (\_ -> Free)) interState
   actualState <- evalUpdate interState' $ proc () ->
     gitUpdate latestRev'' (error "should update") -< ()
@@ -116,14 +116,14 @@ test_gitCalledOnce = do
     $ "State mismatch: " <> show actualState
   where
     latestRev' _ _ = pure "some-other-rev"
-    defaultRefAndHEAD' _ = pure ("some-ref", "some-rev")
+    defaultBranchAndHEAD' _ = pure ("some-branch", "some-rev")
     initialState =
       HMS.fromList
         [("repo", (Free, "git@github.com:nmattia/niv"))]
     expectedState =
       HMS.fromList
         [ ("repo", "git@github.com:nmattia/niv"),
-          ("ref", "some-ref"),
+          ("branch", "some-branch"),
           ("rev", "some-other-rev"),
           ("type", "git")
         ]

src/Niv/Sources.hs

@@ -166,6 +166,8 @@ data SourcesNixVersion
     V20
   | -- Use the source name in fetchurl
     V21
+  | -- Stop setting `ref` and use `branch` and `tag` in sources
+    V22
   deriving stock (Bounded, Enum, Eq)
 
 -- | A user friendly version
@@ -192,6 +194,7 @@ sourcesVersionToText = \case
   V19 -> "19"
   V20 -> "20"
   V21 -> "21"
+  V22 -> "22"
 
 latestVersionMD5 :: T.Text
 latestVersionMD5 = sourcesVersionToMD5 maxBound
@@ -225,6 +228,7 @@ sourcesVersionToMD5 = \case
   V19 -> "543621698065cfc6a4a7985af76df718"
   V20 -> "ab4263aa63ccf44b4e1510149ce14eff"
   V21 -> "c501eee378828f7f49828a140dbdbca3"
+  V22 -> "935d1d2f0bf95fda977a6e3a7e548ed4"
 
 -- | The MD5 sum of ./nix/sources.nix
 sourcesNixMD5 :: IO T.Text