Ensure git scm does not take lock into account when comparing deps, closes #1992

Author: José Valim

lib/mix/lib/mix/scm/git.ex

@@ -60,7 +60,8 @@ defmodule Mix.SCM.Git do
   end
 
   def equal?(opts1, opts2) do
-    get_lock(opts1, false) == get_lock(opts2, false)
+    opts1[:git] == opts2[:git] &&
+      get_lock_opts(opts1) == get_lock_opts(opts2)
   end
 
   def checkout(opts) do
@@ -108,17 +109,12 @@ defmodule Mix.SCM.Git do
       run_cmd_or_raise "git submodule update --init --recursive"
     end
 
-    get_lock(opts, true)
+    get_lock(opts)
   end
 
-  defp get_lock(opts, fresh) do
-    lock = if fresh do
-             rev_info = get_rev_info
-             rev_info[:rev]
-           else
-             get_lock_rev(opts[:lock])
-           end
-    { :git, opts[:git], lock, get_lock_opts(opts) }
+  defp get_lock(opts) do
+    rev_info = get_rev_info
+    { :git, opts[:git], rev_info[:rev], get_lock_opts(opts) }
   end
 
   defp get_lock_rev({ :git, _repo, lock, _opts }) when is_binary(lock), do: lock

lib/mix/test/mix/scm/git_test.exs

@@ -1,7 +1,7 @@
 Code.require_file "../../test_helper.exs", __DIR__
 
 defmodule Mix.SCM.GitTest do
-  use MixTest.Case
+  use MixTest.Case, async: true
 
   test "formats the lock" do
     assert Mix.SCM.Git.format_lock(lock()) == "abcdef0"
@@ -10,6 +10,18 @@ defmodule Mix.SCM.GitTest do
     assert Mix.SCM.Git.format_lock(lock(ref: "abcdef0"))   == "abcdef0 (ref)"
   end
 
+  test "considers to dep equals if the have the same git and the same opts" do
+    assert Mix.SCM.Git.equal?([git: "foo"], [git: "foo"])
+    refute Mix.SCM.Git.equal?([git: "foo"], [git: "bar"])
+
+    assert Mix.SCM.Git.equal?([git: "foo", branch: "master"], [git: "foo", branch: "master"])
+    refute Mix.SCM.Git.equal?([git: "foo", branch: "master"], [git: "foo", branch: "other"])
+  end
+
+  test "lock should not be taken into account when considering deps equal as the lock is shared" do
+    assert Mix.SCM.Git.equal?([git: "foo", lock: 1], [git: "foo", lock: 2])
+  end
+
   defp lock(opts // []) do
     [lock: { :git, "/repo", "abcdef0123456789", opts }]
   end