Fix Github user OAuth connection

lib/code_corps/accounts/accounts.ex

@@ -94,6 +94,7 @@ defmodule CodeCorps.Accounts do
 
     multi =
       Multi.new
+      |> Multi.run(:existing_user, fn _ -> params |> update_existing_user_if_any() end)
       |> Multi.update(:user, changeset)
       |> Multi.run(:installations, fn %{user: %User{} = user} -> user |> associate_installations() end)
       |> Multi.run(:tasks, fn %{user: %User{} = user} -> user |> associate_tasks() end)
@@ -108,6 +109,20 @@ defmodule CodeCorps.Accounts do
     end
   end
 
+  defp update_existing_user_if_any(%{github_id: github_id}) do
+    case Repo.get_by(User, github_id: github_id, sign_up_context: "github") do
+      %User{} = existing_user -> existing_user |> do_update_existing_user()
+      _ -> {:ok, nil}
+    end
+  end
+
+  defp do_update_existing_user(%User{github_id: github_id} = user) do
+    params = %{github_id: nil, github_id_was: github_id}
+    user
+    |> Changesets.dissociate_github_user_changeset(params)
+    |> Repo.update()
+  end
+
   defp upload_github_photo_async(%User{cloudinary_public_id: nil} = user) do
     TaskSupervisor.start_child(:background_processor, fn -> upload_github_photo(user) end)
   end

lib/code_corps/accounts/changesets.ex

@@ -50,6 +50,12 @@ defmodule CodeCorps.Accounts.Changesets do
     |> unique_github_constraint()
   end
 
+  def dissociate_github_user_changeset(struct, %{} = params) do
+    struct
+    |> Changeset.cast(params, [:github_id, :github_id_was])
+    |> unique_github_constraint()
+  end
+
   @spec ensure_email_without_overwriting(Changeset.t, map) :: Changeset.t
   defp ensure_email_without_overwriting(%Changeset{} = changeset, %{"email" => new_email} = _params) do
     case changeset |> Changeset.get_field(:email) do

lib/code_corps/model/user.ex

@@ -27,6 +27,7 @@ defmodule CodeCorps.User do
     field :github_avatar_url, :string
     field :github_email, :string
     field :github_id, :integer
+    field :github_id_was, :integer
     field :github_username, :string
     field :last_name, :string
     field :password, :string, virtual: true

priv/repo/migrations/20171109231538_add_github_id_was.exs

@@ -0,0 +1,9 @@
+defmodule CodeCorps.Repo.Migrations.AddGithubIdWas do
+  use Ecto.Migration
+
+  def change do
+    alter table(:users) do
+      add :github_id_was, :integer
+    end
+  end
+end

priv/repo/structure.sql

@@ -1745,7 +1745,8 @@ CREATE TABLE users (
     github_username character varying(255),
     github_id integer,
     type character varying(255) DEFAULT 'user'::character varying,
-    github_user_id bigint
+    github_user_id bigint,
+    github_id_was integer
 );
 
 
@@ -3867,5 +3868,5 @@ ALTER TABLE ONLY users
 -- PostgreSQL database dump complete
 --
 
-INSERT INTO "schema_migrations" (version) VALUES (20160723215749), (20160804000000), (20160804001111), (20160805132301), (20160805203929), (20160808143454), (20160809214736), (20160810124357), (20160815125009), (20160815143002), (20160816020347), (20160816034021), (20160817220118), (20160818000944), (20160818132546), (20160820113856), (20160820164905), (20160822002438), (20160822004056), (20160822011624), (20160822020401), (20160822044612), (20160830081224), (20160830224802), (20160911233738), (20160912002705), (20160912145957), (20160918003206), (20160928232404), (20161003185918), (20161019090945), (20161019110737), (20161020144622), (20161021131026), (20161031001615), (20161121005339), (20161121014050), (20161121043941), (20161121045709), (20161122015942), (20161123081114), (20161123150943), (20161124085742), (20161125200620), (20161126045705), (20161127054559), (20161205024856), (20161207112519), (20161209192504), (20161212005641), (20161214005935), (20161215052051), (20161216051447), (20161218005913), (20161219160401), (20161219163909), (20161220141753), (20161221085759), (20161226213600), (20161231063614), (20170102130055), (20170102181053), (20170104113708), (20170104212623), (20170104235423), (20170106013143), (20170115035159), (20170115230549), (20170121014100), (20170131234029), (20170201014901), (20170201025454), (20170201035458), (20170201183258), (20170220032224), (20170224233516), (20170226050552), (20170228085250), (20170308214128), (20170308220713), (20170308222552), (20170313130611), (20170318032449), (20170318082740), (20170324194827), (20170424215355), (20170501225441), (20170505224222), (20170526095401), (20170602000208), (20170622205732), (20170626231059), (20170628092119), (20170628213609), (20170629183404), (20170630140136), (20170706132431), (20170707213648), (20170711122252), (20170717092127), (20170725060612), (20170727052644), (20170731130121), (20170814131722), (20170913114958), (20170921014405), (20170925214512), (20170925230419), (20170926134646), (20170927100300), (20170928234412), (20171003134956), (20171003225853), (20171006063358), (20171006161407), (20171012215106), (20171012221231), (20171016125229), (20171016125516), (20171016223356), (20171016235656), (20171017235433), (20171019191035), (20171025184225), (20171026010933), (20171027061833), (20171028011642), (20171028173508), (20171030182857), (20171031232023), (20171031234356), (20171101023309), (20171104013543), (20171106045740), (20171106050209), (20171106103153), (20171106200036);
+INSERT INTO "schema_migrations" (version) VALUES (20160723215749), (20160804000000), (20160804001111), (20160805132301), (20160805203929), (20160808143454), (20160809214736), (20160810124357), (20160815125009), (20160815143002), (20160816020347), (20160816034021), (20160817220118), (20160818000944), (20160818132546), (20160820113856), (20160820164905), (20160822002438), (20160822004056), (20160822011624), (20160822020401), (20160822044612), (20160830081224), (20160830224802), (20160911233738), (20160912002705), (20160912145957), (20160918003206), (20160928232404), (20161003185918), (20161019090945), (20161019110737), (20161020144622), (20161021131026), (20161031001615), (20161121005339), (20161121014050), (20161121043941), (20161121045709), (20161122015942), (20161123081114), (20161123150943), (20161124085742), (20161125200620), (20161126045705), (20161127054559), (20161205024856), (20161207112519), (20161209192504), (20161212005641), (20161214005935), (20161215052051), (20161216051447), (20161218005913), (20161219160401), (20161219163909), (20161220141753), (20161221085759), (20161226213600), (20161231063614), (20170102130055), (20170102181053), (20170104113708), (20170104212623), (20170104235423), (20170106013143), (20170115035159), (20170115230549), (20170121014100), (20170131234029), (20170201014901), (20170201025454), (20170201035458), (20170201183258), (20170220032224), (20170224233516), (20170226050552), (20170228085250), (20170308214128), (20170308220713), (20170308222552), (20170313130611), (20170318032449), (20170318082740), (20170324194827), (20170424215355), (20170501225441), (20170505224222), (20170526095401), (20170602000208), (20170622205732), (20170626231059), (20170628092119), (20170628213609), (20170629183404), (20170630140136), (20170706132431), (20170707213648), (20170711122252), (20170717092127), (20170725060612), (20170727052644), (20170731130121), (20170814131722), (20170913114958), (20170921014405), (20170925214512), (20170925230419), (20170926134646), (20170927100300), (20170928234412), (20171003134956), (20171003225853), (20171006063358), (20171006161407), (20171012215106), (20171012221231), (20171016125229), (20171016125516), (20171016223356), (20171016235656), (20171017235433), (20171019191035), (20171025184225), (20171026010933), (20171027061833), (20171028011642), (20171028173508), (20171030182857), (20171031232023), (20171031234356), (20171101023309), (20171104013543), (20171106045740), (20171106050209), (20171106103153), (20171106200036), (20171109231538);
 

test/lib/code_corps/accounts/accounts_test.exs

@@ -68,17 +68,27 @@ defmodule CodeCorps.AccountsTest do
   describe "update_from_github_oauth/3" do
     test "updates proper user from provided payload" do
       user = insert(:user)
-      params = TestHelpers.load_endpoint_fixture("user")
+      %{"id" => github_id} = params = TestHelpers.load_endpoint_fixture("user")
       token = "random_token"
 
+      {:ok, %User{} = user_for_github_user} =
+        params
+        |> Accounts.create_from_github()
+
       {:ok, %User{} = user} =
         user
         |> Accounts.update_from_github_oauth(params, token)
 
       wait_for_supervisor()
 
+      user_for_github_user = Repo.get(User, user_for_github_user.id)
+
+      assert user_for_github_user.sign_up_context == "github"
+      assert user_for_github_user.github_id_was == github_id
+      refute user_for_github_user.github_id
       assert user.id
       assert user.github_auth_token == token
+      assert user.github_id == github_id
       assert user.sign_up_context == "default"
       assert user.type == "user"
     end