Require parentheses on zero arity functions

@jjcarstens is a firm believer

.credo.exs

@@ -104,8 +104,7 @@
           {Credo.Check.Readability.ModuleNames, []},
           {Credo.Check.Readability.MultiAlias, []},
           {Credo.Check.Readability.ParenthesesInCondition, []},
-          # Disabled as I'm not sure I agree with this one and it requires discussion
-          # {Credo.Check.Readability.ParenthesesOnZeroArityDefs, []},
+          {Credo.Check.Readability.ParenthesesOnZeroArityDefs, [parens: true]},
           {Credo.Check.Readability.PipeIntoAnonymousFunctions, []},
           {Credo.Check.Readability.PredicateFunctionNames, []},
           {Credo.Check.Readability.PreferImplicitTry, []},

lib/nerves_hub/accounts/remove_account.ex

@@ -44,7 +44,7 @@ defmodule NervesHub.Accounts.RemoveAccount do
     |> Repo.transaction()
   end
 
-  defp query_org_users do
+  defp query_org_users() do
     from(
       org_user in OrgUser,
       join: user in assoc(org_user, :user),
@@ -87,7 +87,7 @@ defmodule NervesHub.Accounts.RemoveAccount do
     end)
   end
 
-  defp truncated_utc_now do
+  defp truncated_utc_now() do
     DateTime.truncate(DateTime.utc_now(), :second)
   end
 

lib/nerves_hub/accounts/user.ex

@@ -180,7 +180,7 @@ defmodule NervesHub.Accounts.User do
   The time length that a password reset token is valid.
   Passed to Timex.shift, so it just has to be a keyword list with :minutes, :hours, etc.
   """
-  def password_reset_window do
+  def password_reset_window() do
     [hours: 8]
   end
 

lib/nerves_hub/devices/ca_certificate/csr.ex

@@ -12,7 +12,7 @@ defmodule NervesHub.Devices.CACertificate.CSR do
   after a user creates the CSR.
   """
   @spec generate_code() :: csr_code()
-  def generate_code do
+  def generate_code() do
     :crypto.strong_rand_bytes(32) |> Base.encode16()
   end
 

lib/nerves_hub/devices/metrics.ex

@@ -18,7 +18,7 @@ defmodule NervesHub.Devices.Metrics do
     "mem_used_percent"
   ]
 
-  def default_metrics, do: @default_metrics
+  def default_metrics(), do: @default_metrics
 
   @doc """
   Get all metrics for device

lib/nerves_hub/extensions.ex

@@ -38,9 +38,7 @@ defmodule NervesHub.Extensions do
   Get list of supported extensions as atoms with descriptive text.
   """
   @spec list() :: [:geo | :health, ...]
-  def list do
-    @supported_extensions
-  end
+  def list(), do: @supported_extensions
 
   @spec module(extension()) :: NervesHub.Extensions.Geo | NervesHub.Extensions.Health
   def module(:health), do: NervesHub.Extensions.Health

lib/nerves_hub/extensions/geo.ex

@@ -4,7 +4,7 @@ defmodule NervesHub.Extensions.Geo do
   alias NervesHub.Devices
 
   @impl NervesHub.Extensions
-  def description do
+  def description() do
     """
     Reporting of GeoIP information or custom geo-location information sources
     you've set up for your device.

lib/nerves_hub/extensions/health.ex

@@ -8,7 +8,7 @@ defmodule NervesHub.Extensions.Health do
   require Logger
 
   @impl NervesHub.Extensions
-  def description do
+  def description() do
     """
     Reporting of fundamental device metrics, metadata, alarms and more.
     Also supports custom metrics. Alarms require an alarm handler to be set.

lib/nerves_hub/firmwares/upload/s3.ex

@@ -55,7 +55,7 @@ defmodule NervesHub.Firmwares.Upload.S3 do
     %{"s3_key" => Path.join([key_prefix(), Integer.to_string(org_id), filename])}
   end
 
-  def bucket do
+  def bucket() do
     Application.get_env(:nerves_hub, __MODULE__)[:bucket]
   end
 

lib/nerves_hub/products.ex

@@ -20,7 +20,7 @@ defmodule NervesHub.Products do
   @csv_certs_sep "\n\n"
   @csv_header ["identifier", "description", "tags", "product", "org", "certificates"]
 
-  def __csv_header__, do: @csv_header
+  def __csv_header__(), do: @csv_header
 
   @spec get_products_by_user_and_org(User.t(), Org.t()) :: [Product.t()]
   def get_products_by_user_and_org(%User{id: user_id}, %Org{id: org_id}) do

lib/nerves_hub/types.ex

@@ -2,7 +2,7 @@ defmodule NervesHub.Types do
   defmodule Tag do
     @behaviour Ecto.Type
 
-    def type, do: {:array, :string}
+    def type(), do: {:array, :string}
 
     def embed_as(_), do: :self
 
@@ -33,7 +33,7 @@ defmodule NervesHub.Types do
   defmodule Resource do
     @behaviour Ecto.Type
 
-    def type, do: :string
+    def type(), do: :string
 
     def embed_as(_), do: :self
 
@@ -69,7 +69,7 @@ defmodule NervesHub.Types do
 
     def load(resource), do: {:ok, String.to_existing_atom(resource)}
 
-    defp allowed_resources do
+    defp allowed_resources() do
       [
         "Elixir.NervesHub.Accounts.Org",
         "Elixir.NervesHub.Accounts.User",

lib/nerves_hub/views/email_view.ex

@@ -5,7 +5,7 @@ defmodule NervesHub.EmailView do
 
   import Phoenix.HTML
 
-  def base_url do
+  def base_url() do
     config = Application.get_env(:nerves_hub, NervesHubWeb.Endpoint)
 
     port =
@@ -21,7 +21,7 @@ defmodule NervesHub.EmailView do
   Standard closing words.
   """
 
-  def closing do
+  def closing() do
     """
         #{closing_message()}
 

lib/nerves_hub_web.ex

@@ -17,16 +17,16 @@ defmodule NervesHubWeb do
   and import those modules here.
   """
 
-  def static_paths, do: ~w(assets fonts images favicon.ico robots.txt)
+  def static_paths(), do: ~w(assets fonts images favicon.ico robots.txt)
 
-  def plug do
+  def plug() do
     quote do
       import Plug.Conn
       import Phoenix.Controller
     end
   end
 
-  def controller do
+  def controller() do
     quote do
       use Phoenix.Controller, namespace: NervesHubWeb
       use Gettext, backend: NervesHubWeb.Gettext
@@ -50,7 +50,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def api_controller do
+  def api_controller() do
     quote do
       use Phoenix.Controller, namespace: NervesHubWeb
       use Gettext, backend: NervesHubWeb.Gettext
@@ -71,7 +71,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def updated_live_view do
+  def updated_live_view() do
     quote do
       use NervesHubWeb.LiveView,
         layout: {NervesHubWeb.LayoutView, :live},
@@ -110,7 +110,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def verified_routes do
+  def verified_routes() do
     quote do
       use Phoenix.VerifiedRoutes,
         endpoint: NervesHubWeb.Endpoint,
@@ -119,15 +119,15 @@ defmodule NervesHubWeb do
     end
   end
 
-  def live_component do
+  def live_component() do
     quote do
       use Phoenix.LiveComponent
 
       unquote(view_helpers())
     end
   end
 
-  def html do
+  def html() do
     quote do
       use Phoenix.Component
 
@@ -140,7 +140,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  defp html_helpers do
+  defp html_helpers() do
     quote do
       # HTML escaping functionality
       import Phoenix.HTML
@@ -156,7 +156,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def view do
+  def view() do
     quote do
       use Phoenix.View,
         root: "lib/nerves_hub_web/templates",
@@ -183,7 +183,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def api_view do
+  def api_view() do
     quote do
       use Phoenix.View,
         root: "lib/nerves_hub_web/templates",
@@ -206,7 +206,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def component do
+  def component() do
     quote do
       use Phoenix.Component
 
@@ -215,7 +215,7 @@ defmodule NervesHubWeb do
     end
   end
 
-  def router do
+  def router() do
     quote do
       use Phoenix.Router
       import Plug.Conn
@@ -224,14 +224,14 @@ defmodule NervesHubWeb do
     end
   end
 
-  def channel do
+  def channel() do
     quote do
       use Phoenix.Channel
       use Gettext, backend: NervesHubWeb.Gettext
     end
   end
 
-  defp view_helpers do
+  defp view_helpers() do
     quote do
       # Use all HTML functionality (forms, tags, etc)
       use Phoenix.HTML

lib/nerves_hub_web/live/dashboard/index.ex

@@ -159,7 +159,7 @@ defmodule NervesHubWeb.Live.Dashboard.Index do
     :ok
   end
 
-  defp time do
+  defp time() do
     System.monotonic_time(:millisecond)
   end
 end

lib/nerves_hub_web/live/devices/settings.ex

@@ -151,7 +151,7 @@ defmodule NervesHubWeb.Live.Devices.Settings do
     {:ok, socket}
   end
 
-  defp extensions do
+  defp extensions() do
     for extension <- Extensions.list(),
         into: %{},
         do: {extension, Extensions.module(extension).description()}

lib/nerves_hub_web/live/org/products.ex

@@ -56,7 +56,7 @@ defmodule NervesHubWeb.Live.Org.Products do
     end
   end
 
-  defp extensions do
+  defp extensions() do
     for extension <- Extensions.list(),
         into: %{},
         do: {extension, Extensions.module(extension).description()}

lib/nerves_hub_web/live/product/settings.ex

@@ -99,7 +99,7 @@ defmodule NervesHubWeb.Live.Product.Settings do
     {:noreply, socket}
   end
 
-  defp extensions do
+  defp extensions() do
     for extension <- Extensions.list(),
         into: %{},
         do: {extension, Extensions.module(extension).description()}

test/support/fixtures.ex

@@ -438,11 +438,11 @@ defmodule NervesHub.Fixtures do
     }
   end
 
-  defp counter do
+  defp counter() do
     System.unique_integer([:positive])
   end
 
-  defp counter_in_alpha do
+  defp counter_in_alpha() do
     counter()
     |> Integer.to_string()
     |> String.split("")