refactor: add possibility to choose which features to generate with CLI

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - BREAKING CHANGE: The JSON library is now configurable via the `:json_library` option at compile time
+- BREAKING CHANGE: Configuration of features to generate via the CLI mix task is done with the `--generate` argument
 - Drop support for Elixir < 1.15
 - Use `Jason.encode_to_iodata!` rather than `Jason.encode!` for default JSON encoding
 

README.md

@@ -500,8 +500,8 @@ The generated file will be usable in any project as long as `protox` is declared
 * `--namespace`
   Prepends a [namespace](#prepend-namespaces) to all generated modules.
 
-* `--keep-unknown-fields=[true|false]`
-  Toggles support of [unknown fields](#unknown-fields). Default to `true`.
+* `--generate=none|all|unknown_fields`
+  Toggles support of features to generate. Currently, only `unknown_fields` is supported.
 
 ## Conformance
 

lib/mix/tasks/protox/generate.ex

@@ -25,18 +25,31 @@ defmodule Mix.Tasks.Protox.Generate do
     include_path: :keep,
     namespace: :string,
     multiple_files: :boolean,
-    keep_unknown_fields: :boolean
+    generate: :string
   ]
 
+  @default_generate_opt_all [
+    keep_unknown_fields: true
+  ]
+
+  @default_generate_opt_none [
+    keep_unknown_fields: false
+  ]
+
+  @map_generate_opts %{
+    "unknown_fields" => {:keep_unknown_fields, true}
+  }
+
   @impl Mix.Task
   @spec run(any) :: any
   def run(args) do
     with {opts, files, []} <- OptionParser.parse(args, strict: @options),
          {:ok, output_path} <- Keyword.fetch(opts, :output_path),
          {include_paths, opts} = Keyword.pop_values(opts, :include_path),
          {multiple_files, opts} = Keyword.pop(opts, :multiple_files, false),
-         {:ok, files_content} <-
-           generate(files, output_path, multiple_files, include_paths, opts) do
+         {generate_opts, opts} = Keyword.pop(opts, :generate, "all"),
+         opts <- transform_generate_opts(generate_opts, opts),
+         {:ok, files_content} <- generate(files, output_path, multiple_files, include_paths, opts) do
       Enum.each(files_content, &generate_file/1)
     else
       err ->
@@ -47,6 +60,16 @@ defmodule Mix.Tasks.Protox.Generate do
 
   # -- Private
 
+  defp transform_generate_opts("all", opts), do: opts ++ @default_generate_opt_all
+  defp transform_generate_opts("none", opts), do: opts ++ @default_generate_opt_none
+
+  defp transform_generate_opts(generate_opts, opts) when is_binary(generate_opts) do
+    generate_opts
+    |> String.split(",")
+    |> Enum.map(&Map.fetch!(@map_generate_opts, &1))
+    |> Enum.concat(opts)
+  end
+
   defp generate_file(%Protox.Generate.FileContent{name: file_name, content: content}) do
     File.write!(file_name, content)
   end

test/code_generation_test.exs

@@ -31,7 +31,7 @@ defmodule Protox.CodeGenerationTest do
     code_generation_path: path,
     protox_path: protox_path
   } do
-    launch(path, protox_path, "single_without_unknown_fields.ex", ["--keep-unknown-fields=false"])
+    launch(path, protox_path, "single_without_unknown_fields.ex", ["--generate=none"])
   end
 
   test "Generate multiple files, with unknown fields", %{
@@ -45,7 +45,7 @@ defmodule Protox.CodeGenerationTest do
     code_generation_path: path,
     protox_path: protox_path
   } do
-    launch(path, protox_path, ".", ["--multiple-files", "--keep-unknown-fields=false"])
+    launch(path, protox_path, ".", ["--multiple-files", "--generate=none"])
   end
 
   test "Generate single file, with namespace", %{