go: remove renameImports and use goPackageAliases

doc/language-support.xml

···
 <programlisting>
 net = buildGoPackage rec {
   name = "go.net-${rev}";
-  goPackagePath = "code.google.com/p/go.net"; <co xml:id='ex-buildGoPackage-1' />
+  goPackagePath = "golang.org/x/net"; <co xml:id='ex-buildGoPackage-1' />
   subPackages = [ "ipv4" "ipv6" ]; <co xml:id='ex-buildGoPackage-2' />
-  rev = "28ff664507e4";
-  src = fetchhg {
+  rev = "e0403b4e005";
+  src = fetchFromGitHub {
     inherit rev;
-    url = "https://${goPackagePath}";
-    sha256 = "1lkz4c9pyz3yz2yz18hiycvlfhgy3jxp68bs7mv7bcfpaj729qav";
+    owner = "golang";
+    repo = "net";
+    sha256 = "1g7cjzw4g4301a3yqpbk8n1d4s97sfby2aysl275x04g0zh8jxqp";
   };
-  renameImports = [ <co xml:id='ex-buildGoPackage-3' />
-    "code.google.com/p/go.crypto golang.org/x/crypto"
-    "code.google.com/p/goprotobuf github.com/golang/protobuf"
-  ];
+  goPackageAliases = [ "code.google.com/p/go.net" ]; <co xml:id='ex-buildGoPackage-3' />
   propagatedBuildInputs = [ goPackages.text ]; <co xml:id='ex-buildGoPackage-4' />
   buildFlags = "--tags release"; <co xml:id='ex-buildGoPackage-5' />
 };
···
     </para>
   </callout>
 
-  <callout arearefs='ex-buildGoPackage-4'>
+  <callout arearefs='ex-buildGoPackage-3'>
     <para>
-      <varname>renameImports</varname> is a list of import paths to be renamed before
-      building the package. The path to be renamed can be a regular expression.
+      <varname>goPackageAliases</varname> is a list of alternative import paths
+      that are valid for this library.
+      Packages that depend on this library will automatically rename
+      import paths that match any of the aliases to <literal>goPackagePath</literal>.
     </para>
     <para>
       In this example imports will be renamed from
-      <literal>code.google.com/p/go.crypto</literal> to
-      <literal>golang.org/x/crypto</literal> and from
-      <literal>code.google.com/p/goprotobuf</literal> to
-      <literal>github.com/golang/protobuf</literal>.
+      <literal>code.google.com/p/go.net</literal> to
+      <literal>golang.org/x/net</literal> in every package that depend on the
+      <literal>go.net</literal> library.
     </para>
   </callout>
 

pkgs/applications/networking/pond/default.nix

···
 
   subPackages = [ "client" ];
 
-  renameImports = [
-    "code.google.com/p/go.crypto golang.org/x/crypto"
-    "code.google.com/p/goprotobuf github.com/golang/protobuf"
-  ];
-
   buildInputs = [ trousers net crypto protobuf ed25519 govers ];
     
   buildFlags = "--tags nogui";

pkgs/development/go-modules/generic/default.nix

···
 # Go import path of the package
 , goPackagePath
 
+# Go package aliases
+, goPackageAliases ? [ ]
+
 # Extra sources to include in the gopath
 , extraSrcs ? [ ]
 
+, dontRenameImports ? false
+
 , meta ? {}, ... } @ args':
 
 let
   args = lib.filterAttrs (name: _: name != "extraSrcs") args';
 in
 
-go.stdenv.mkDerivation ( args // {
+go.stdenv.mkDerivation (
+  (builtins.removeAttrs args [ "goPackageAliases" ]) // {
+
   name = "go${go.meta.branch}-${name}";
-  buildInputs = [ go ] ++ buildInputs ++ (lib.optional (args ? renameImports) govers) ;
+  buildInputs = [ go ] ++ buildInputs ++ (lib.optional (!dontRenameImports) govers) ;
 
   configurePhase = args.configurePhase or ''
     runHook preConfigure
···
     runHook postConfigure
   '';
 
-  renameImports = lib.optionalString (args ? renameImports)
-                    (lib.concatMapStringsSep "\n"
-                      (cmdargs: "govers -m ${cmdargs}")
-                      args.renameImports);
+  renameImports = args.renameImports or (
+    let
+      inputsWithAliases = lib.filter (x: x ? goPackageAliases) buildInputs;
+      rename = to: from: "echo Renaming '${from}' to '${to}'; govers -m ${from} ${to}";
+      renames = p: lib.concatMapStringsSep "\n" (rename p.goPackagePath) p.goPackageAliases;
+    in lib.concatMapStringsSep "\n" renames inputsWithAliases);
 
   buildPhase = args.buildPhase or ''
     runHook preBuild
···
 
     runHook postInstall
   '';
+
+  passthru = lib.optionalAttrs (goPackageAliases != []) { inherit goPackageAliases; };
 
   meta = meta // {
     # add an extra maintainer to every package

pkgs/top-level/go-packages.nix

···
     rev = "4d48e5fa3d62b5e6e71260571bf76c767198ca02";
     name = "go-crypto-${rev}";
     goPackagePath = "golang.org/x/crypto";
+    goPackageAliases = [ "code.google.com/p/go.crypto" ];
 
     src = fetchFromGitHub {
       inherit rev;
···
     rev = "e0403b4e005737430c05a57aac078479844f919c";
     name = "net-${stdenv.lib.strings.substring 0 7 rev}";
     goPackagePath = "golang.org/x/net";
+    goPackageAliases = [ "code.google.com/p/go.net" ];
 
     src = fetchFromGitHub {
       inherit rev;
···
     rev = "efd7476481382c195beb33acd8ec2f1527167fb4";
     name = "goprotobuf-${stdenv.lib.strings.substring 0 7 rev}";
     goPackagePath = "github.com/golang/protobuf";
+    goPackageAliases = [ "code.google.com/p/goprotobuf" ];
 
     src = fetchFromGitHub {
       inherit rev;
···
     rev = "3b5f175f65d601d06f48d78fcbdb0add633565b9";
     name = "govers-${stdenv.lib.strings.substring 0 7 rev}";
     goPackagePath = "github.com/rogpeppe/govers";
+    dontRenameImports = true;
     src = fetchFromGitHub {
       inherit rev;
       owner = "rogpeppe";