refactor: incorporate Credo changes

.credo.exs

@@ -114,7 +114,8 @@
          [
            order:
              ~w(moduledoc behaviour use import require alias module_attribute defstruct callback macrocallback optional_callback)a,
-           ignore: [:type]
+           ignore: [:type],
+           ignore_module_attributes: [:tag, :trace]
          ]},
         {Credo.Check.Readability.StringSigils, []},
         {Credo.Check.Readability.TrailingBlankLine, []},
@@ -158,7 +159,7 @@
         {Credo.Check.Warning.MapGetUnsafePass, []},
         # disabling this check by default, as if not included, it will be
         # run on version 1.7.0 and above
-        {Credo.Check.Warning.MissedMetadataKeyInLoggerConfig, false},
+        {Credo.Check.Warning.MissedMetadataKeyInLoggerConfig, []},
         {Credo.Check.Warning.MixEnv, []},
         {Credo.Check.Warning.OperationOnSameValues, []},
         {Credo.Check.Warning.OperationWithConstantResult, []},

.formatter.exs

@@ -1,7 +1,7 @@
 # This file is synced with beam-community/common-config. Any changes will be overwritten.
 
 [
-  import_deps: [],
+  import_deps: [:plug],
   inputs: ["*.{heex,ex,exs}", "{config,lib,priv,test}/**/*.{heex,ex,exs}"],
   line_length: 120,
   plugins: []

lib/bamboo/adapters/local_adapter.ex

@@ -1,3 +1,4 @@
+# credo:disable-for-this-file Credo.Check.Warning.LeakyEnvironment
 defmodule Bamboo.LocalAdapter do
   @moduledoc """
   Stores emails locally. Can be queried to see sent emails.
@@ -25,11 +26,10 @@ defmodule Bamboo.LocalAdapter do
         use Bamboo.Mailer, otp_app: :my_app
       end
   """
+  @behaviour Bamboo.Adapter
 
   alias Bamboo.SentEmail
 
-  @behaviour Bamboo.Adapter
-
   @doc "Adds email to `Bamboo.SentEmail`, can automatically open it in new browser tab"
   def deliver(email, %{open_email_in_browser_url: open_email_in_browser_url}) do
     delivered_email = SentEmail.push(email)

lib/bamboo/adapters/mailgun_adapter.ex

@@ -44,14 +44,19 @@ defmodule Bamboo.MailgunAdapter do
         base_uri: "https://api.eu.mailgun.net/v3"
 
   """
-
-  @service_name "Mailgun"
-  @default_base_uri "https://api.mailgun.net/v3"
   @behaviour Bamboo.Adapter
 
-  alias Bamboo.{Email, Attachment, AdapterHelper}
   import Bamboo.ApiError
 
+  alias Bamboo.AdapterHelper
+  alias Bamboo.Attachment
+  alias Bamboo.Email
+
+  @default_base_uri "https://api.mailgun.net/v3"
+  @internal_fields ~w(attachments)a
+  @mailgun_message_fields ~w(from to cc bcc subject text html template recipient-variables)a
+  @service_name "Mailgun"
+
   @doc false
   def handle_config(config) do
     config
@@ -60,20 +65,21 @@ defmodule Bamboo.MailgunAdapter do
     |> Map.put_new(:base_uri, base_uri())
   end
 
-  defp base_uri() do
+  defp base_uri do
     Application.get_env(:bamboo, :mailgun_base_uri, @default_base_uri)
   end
 
   defp get_setting(config, key) do
-    config[key]
-    |> case do
-      {:system, var} ->
-        System.get_env(var)
+    config_value =
+      case config[key] do
+        {:system, var} ->
+          System.get_env(var)
 
-      value ->
-        value
-    end
-    |> case do
+        value ->
+          value
+      end
+
+    case config_value do
       value when value in [nil, ""] ->
         raise_missing_setting_error(config, key)
 
@@ -95,13 +101,10 @@ defmodule Bamboo.MailgunAdapter do
   def deliver(email, config) do
     body = to_mailgun_body(email)
     config = handle_config(config)
+    uri = full_uri(config)
+    headers = headers(email, config)
 
-    case :hackney.post(
-           full_uri(config),
-           headers(email, config),
-           body,
-           AdapterHelper.hackney_opts(config)
-         ) do
+    case :hackney.post(uri, headers, body, AdapterHelper.hackney_opts(config)) do
       {:ok, status, _headers, response} when status > 299 ->
         body = decode_body(body)
         {:error, build_api_error(@service_name, response, body)}
@@ -171,9 +174,7 @@ defmodule Bamboo.MailgunAdapter do
   defp put_bcc(body, %Email{bcc: bcc}), do: Map.put(body, :bcc, prepare_recipients(bcc))
 
   defp prepare_recipients(recipients) do
-    recipients
-    |> Enum.map(&prepare_recipient(&1))
-    |> Enum.join(",")
+    Enum.map_join(recipients, ",", &prepare_recipient(&1))
   end
 
   defp prepare_recipient({nil, address}), do: address
@@ -190,6 +191,7 @@ defmodule Bamboo.MailgunAdapter do
 
   defp put_headers(body, %Email{headers: headers}) do
     Enum.reduce(headers, body, fn {key, value}, acc ->
+      # credo:disable-for-this-file Credo.Check.Warning.UnsafeToAtom
       Map.put(acc, :"h:#{key}", value)
     end)
   end
@@ -223,6 +225,7 @@ defmodule Bamboo.MailgunAdapter do
     custom_vars = Map.get(private, :mailgun_custom_vars, %{})
 
     Enum.reduce(custom_vars, body, fn {key, value}, acc ->
+      # credo:disable-for-this-file Credo.Check.Warning.UnsafeToAtom
       Map.put(acc, :"v:#{key}", value)
     end)
   end
@@ -240,10 +243,7 @@ defmodule Bamboo.MailgunAdapter do
   defp put_attachments(body, %Email{attachments: []}), do: body
 
   defp put_attachments(body, %Email{attachments: attachments}) do
-    attachment_data =
-      attachments
-      |> Enum.reverse()
-      |> Enum.map(&prepare_file(&1))
+    attachment_data = Enum.map(attachments, &prepare_file(&1))
 
     Map.put(body, :attachments, attachment_data)
   end
@@ -252,14 +252,12 @@ defmodule Bamboo.MailgunAdapter do
     {"", attachment.data, {"form-data", [{"name", ~s/"attachment"/}, {"filename", ~s/"#{attachment.filename}"/}]}, []}
   end
 
-  @mailgun_message_fields ~w(from to cc bcc subject text html template recipient-variables)a
-  @internal_fields ~w(attachments)a
-
   def filter_non_empty_mailgun_fields(body) do
-    Enum.filter(body, fn {key, value} ->
+    body
+    |> Enum.filter(fn {key, value} ->
       # Key is a well known mailgun field (including header and custom var field) and its value is not empty
       (key in @mailgun_message_fields || key in @internal_fields ||
-         String.starts_with?(Atom.to_string(key), ["h:", "v:", "o:", "t:"])) &&
+         key |> Atom.to_string() |> String.starts_with?(["h:", "v:", "o:", "t:"])) &&
         !(value in [nil, "", []])
     end)
     |> Enum.into(%{})

lib/bamboo/adapters/mailgun_helper.ex

@@ -113,7 +113,7 @@ defmodule Bamboo.MailgunHelper do
       |> MailgunHelper.substitute_variables(%{ "greeting" => "Hello!", "password_reset_link" => "https://example.com/123" })
 
   """
-  def substitute_variables(%Email{headers: headers} = email, variables = %{}) do
+  def substitute_variables(%Email{headers: headers} = email, %{} = variables) do
     custom_vars =
       headers
       |> Map.get(@mailgun_header_for_custom_vars, "{}")

lib/bamboo/adapters/mandrill_adapter.ex

@@ -21,15 +21,16 @@ defmodule Bamboo.MandrillAdapter do
         use Bamboo.Mailer, otp_app: :my_app
       end
   """
+  @behaviour Bamboo.Adapter
+
+  import Bamboo.ApiError
+
+  alias Bamboo.AdapterHelper
 
-  @service_name "Mandrill"
   @default_base_uri "https://mandrillapp.com"
   @send_message_path "api/1.0/messages/send.json"
   @send_message_template_path "api/1.0/messages/send-template.json"
-  @behaviour Bamboo.Adapter
-
-  alias Bamboo.AdapterHelper
-  import Bamboo.ApiError
+  @service_name "Mandrill"
 
   def deliver(email, config) do
     api_key = get_key(config)
@@ -81,8 +82,7 @@ defmodule Bamboo.MandrillAdapter do
   end
 
   defp convert_to_mandrill_params(email, api_key) do
-    %{key: api_key, message: message_params(email)}
-    |> maybe_put_template_params(email)
+    maybe_put_template_params(%{key: api_key, message: message_params(email)}, email)
   end
 
   defp maybe_put_template_params(params, %{
@@ -97,8 +97,8 @@ defmodule Bamboo.MandrillAdapter do
 
   defp message_params(email) do
     %{
-      from_name: email.from |> elem(0),
-      from_email: email.from |> elem(1),
+      from_name: elem(email.from, 0),
+      from_email: elem(email.from, 1),
       to: recipients(email),
       subject: email.subject,
       text: email.text_body,
@@ -113,7 +113,7 @@ defmodule Bamboo.MandrillAdapter do
     {images, files} =
       attachments
       |> Enum.reverse()
-      |> Enum.split_with(&is_inline_image?/1)
+      |> Enum.split_with(&inline_image?/1)
 
     mandrill_message
     |> Map.put(:attachments, format_attachments(files))
@@ -130,7 +130,7 @@ defmodule Bamboo.MandrillAdapter do
 
   defp format_attachments(attachments) do
     Enum.map(attachments, fn attachment ->
-      name = if is_inline_image?(attachment), do: attachment.content_id, else: attachment.filename
+      name = if inline_image?(attachment), do: attachment.content_id, else: attachment.filename
 
       %{
         name: name,
@@ -140,10 +140,10 @@ defmodule Bamboo.MandrillAdapter do
     end)
   end
 
-  defp is_inline_image?(%_{content_type: "image/" <> _, content_id: cid}) when not is_nil(cid),
+  defp inline_image?(%_{content_type: "image/" <> _, content_id: cid}) when is_binary(cid),
     do: true
 
-  defp is_inline_image?(_), do: false
+  defp inline_image?(_), do: false
 
   defp recipients(email) do
     []
@@ -154,14 +154,14 @@ defmodule Bamboo.MandrillAdapter do
 
   defp add_recipients(recipients, new_recipients, type: recipient_type) do
     Enum.reduce(new_recipients, recipients, fn recipient, recipients ->
-      recipients ++
-        [
-          %{
-            name: recipient |> elem(0),
-            email: recipient |> elem(1),
-            type: recipient_type
-          }
-        ]
+      [
+        %{
+          name: elem(recipient, 0),
+          email: elem(recipient, 1),
+          type: recipient_type
+        }
+        | recipients
+      ]
     end)
   end
 

lib/bamboo/adapters/mandrill_helper.ex

@@ -78,11 +78,12 @@ defmodule Bamboo.MandrillHelper do
         }
       end)
 
-    email |> put_param("merge_vars", merge_vars)
+    put_param(email, "merge_vars", merge_vars)
   end
 
   defp merge_vars(e, fun) do
-    fun.(e)
+    e
+    |> fun.()
     |> Enum.map(fn {key, value} ->
       %{
         name: to_string(key),