Respect :path when tar-ing releases, closes #9949

Author: josevalim

lib/mix/lib/mix/tasks/release.ex

@@ -481,7 +481,9 @@ defmodule Mix.Tasks.Release do
   will receive a `Mix.Release` struct and must return the same or
   an updated `Mix.Release` struct. It is also possible to build a tarball
   of the release by passing the `:tar` step anywhere after `:assemble`.
-  The tarball is created in `_build/MIX_ENV/RELEASE_NAME-RELEASE_VSN.tar.gz`
+  If the release `:path` is not configured, the tarball is created in
+  `_build/MIX_ENV/RELEASE_NAME-RELEASE_VSN.tar.gz` Otherwise it is
+  created inside the configured `:path`.
 
   See `Mix.Release` for more documentation on the struct and which
   fields can be modified. Note that `:steps` field itself can be
@@ -1065,8 +1067,16 @@ defmodule Mix.Tasks.Release do
   end
 
   defp make_tar(release) do
-    tar_filename = "#{release.name}-#{release.version}.tar.gz"
-    out_path = Path.join([release.path, "..", "..", tar_filename]) |> Path.expand()
+    build_path = Mix.Project.build_path()
+
+    dir_path =
+      if release.path == Path.join([build_path, "rel", Atom.to_string(release.name)]) do
+        build_path
+      else
+        release.path
+      end
+
+    out_path = Path.join(dir_path, "#{release.name}-#{release.version}.tar.gz")
     info(release, [:green, "* building ", :reset, out_path])
 
     lib_dirs =

lib/mix/test/mix/tasks/release_test.exs

@@ -135,7 +135,7 @@ defmodule Mix.Tasks.ReleaseTest do
   end
 
   describe "tar" do
-    test "with ERTS" do
+    test "with default options" do
       in_fixture("release_test", fn ->
         config = [releases: [demo: [steps: [:assemble, :tar]]]]
 
@@ -186,15 +186,13 @@ defmodule Mix.Tasks.ReleaseTest do
       end)
     end
 
-    test "without ERTS" do
+    test "without ERTS and custom path" do
       in_fixture("release_test", fn ->
-        config = [releases: [demo: [include_erts: false, steps: [:assemble, :tar]]]]
+        config = [releases: [demo: [include_erts: false, path: "tmp/rel", steps: [:assemble, :tar]]]]
 
         Mix.Project.in_project(:release_test, ".", config, fn _ ->
-          root = Path.absname("_build/#{Mix.env()}/rel/demo")
-
           Mix.Task.run("release")
-          tar_path = Path.expand(Path.join([root, "..", "..", "demo-0.1.0.tar.gz"]))
+          tar_path = Path.expand(Path.join(["tmp", "rel", "demo-0.1.0.tar.gz"]))
           message = "* building #{tar_path}"
           assert_received {:mix_shell, :info, [^message]}
           assert File.exists?(tar_path)