Add config option to CLI

Fixes #478

Author: kddnewton

lib/syntax_tree/cli.rb

@@ -455,17 +455,26 @@ def run(item)
       #{Color.bold("stree write [--plugins=...] [--print-width=NUMBER] [-e SCRIPT] FILE")}
         Read, format, and write back the source of the given files
 
+      --ignore-files=...
+        A glob pattern to ignore files when processing. This can be specified
+        multiple times to ignore multiple patterns.
+
       --plugins=...
         A comma-separated list of plugins to load.
 
-      --print-width=NUMBER
+      --print-width=...
         The maximum line width to use when formatting.
 
-      -e SCRIPT
+      -e ...
         Parse an inline string.
 
-      --extension=EXTENSION
-        A file extension matching the content passed in via STDIN or -e. Defaults to 'rb'
+      --extension=...
+        A file extension matching the content passed in via STDIN or -e.
+        Defaults to '.rb'.
+
+      --config=...
+        Path to a configuration file. Defaults to .streerc in the current
+        working directory.
     HELP
 
     # This represents all of the options that can be passed to the CLI. It is
@@ -563,8 +572,16 @@ class ConfigFile
 
       attr_reader :filepath
 
-      def initialize
-        @filepath = File.join(Dir.pwd, FILENAME)
+      def initialize(filepath = nil)
+        if filepath
+          if File.readable?(filepath)
+            @filepath = filepath
+          else
+            raise ArgumentError, "Invalid configuration file: #{filepath}"
+          end
+        else
+          @filepath = File.join(Dir.pwd, FILENAME)
+        end
       end
 
       def exists?
@@ -582,8 +599,24 @@ class << self
       def run(argv)
         name, *arguments = argv
 
-        config_file = ConfigFile.new
-        arguments.unshift(*config_file.arguments)
+        # First, we need to check if there's a --config option specified
+        # so we can use the custom config file path.
+        config_filepath = nil
+        arguments.each_with_index do |arg, index|
+          if arg.start_with?("--config=")
+            config_filepath = arg.split("=", 2)[1]
+            arguments.delete_at(index)
+            break
+          elsif arg == "--config" && arguments[index + 1]
+            config_filepath = arguments[index + 1]
+            arguments.delete_at(index + 1)
+            arguments.delete_at(index)
+            break
+          end
+        end
+
+        config_file = ConfigFile.new(config_filepath)
+        arguments = config_file.arguments.concat(arguments)
 
         options = Options.new
         options.parse(arguments)

test/cli_test.rb

@@ -308,6 +308,48 @@ def test_plugin_args_with_config_file
       end
     end
 
+    def test_config_file_custom_path
+      with_plugin_directory do |directory|
+        plugin = directory.plugin("puts 'Custom config!'")
+        config = <<~TXT
+        --print-width=80
+        --plugins=#{plugin}
+        TXT
+
+        filepath = File.join(Dir.tmpdir, "#{SecureRandom.hex}.streerc")
+        with_config_file(config, filepath) do
+          contents = "#{"a" * 30} + #{"b" * 30}\n"
+          result = run_cli("format", "--config=#{filepath}", contents: contents)
+
+          assert_equal("Custom config!\n#{contents}", result.stdio)
+        end
+      end
+    end
+
+    def test_config_file_custom_path_space_separated
+      with_plugin_directory do |directory|
+        plugin = directory.plugin("puts 'Custom config space!'")
+        config = <<~TXT
+        --print-width=80
+        --plugins=#{plugin}
+        TXT
+
+        filepath = File.join(Dir.tmpdir, "#{SecureRandom.hex}.streerc")
+        with_config_file(config, filepath) do
+          contents = "#{"a" * 30} + #{"b" * 30}\n"
+          result = run_cli("format", "--config", filepath, contents: contents)
+
+          assert_equal("Custom config space!\n#{contents}", result.stdio)
+        end
+      end
+    end
+
+    def test_config_file_nonexistent_path
+      assert_raises(ArgumentError) do
+        run_cli("format", "--config=/nonexistent/path.streerc")
+      end
+    end
+
     Result = Struct.new(:status, :stdio, :stderr, keyword_init: true)
 
     private
@@ -342,8 +384,8 @@ def run_cli(command, *args, contents: :default)
       tempfile.unlink
     end
 
-    def with_config_file(contents)
-      filepath = File.join(Dir.pwd, SyntaxTree::CLI::ConfigFile::FILENAME)
+    def with_config_file(contents, filepath = nil)
+      filepath ||= File.join(Dir.pwd, SyntaxTree::CLI::ConfigFile::FILENAME)
       File.write(filepath, contents)
 
       yield