From 3ad86d2ee247e1d60e9f3d6914b3d0a7deaa6249 Mon Sep 17 00:00:00 2001
From: "Charles-P. Clermont" <charles@cpclermont.com>
Date: Thu, 9 Sep 2021 09:10:37 -0400
Subject: [PATCH] Write JSON to file, not a Ruby Hash.

Fixes #432
---
 lib/theme_check/corrector.rb |  2 +-
 lib/theme_check/json_file.rb | 13 +++++++++----
 test/json_file_test.rb       |  9 +++++++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/lib/theme_check/corrector.rb b/lib/theme_check/corrector.rb
index d06d9947..124823ed 100644
--- a/lib/theme_check/corrector.rb
+++ b/lib/theme_check/corrector.rb
@@ -34,7 +34,7 @@ def create(theme, relative_path, content)
 
     def create_default_locale_json(theme)
       theme.default_locale_json = JsonFile.new("locales/#{theme.default_locale}.default.json", theme.storage)
-      theme.default_locale_json.update_contents('{}')
+      theme.default_locale_json.update_contents({})
     end
   end
 end
diff --git a/lib/theme_check/json_file.rb b/lib/theme_check/json_file.rb
index 75d5a02c..f91060b6 100644
--- a/lib/theme_check/json_file.rb
+++ b/lib/theme_check/json_file.rb
@@ -20,14 +20,19 @@ def parse_error
       @parser_error
     end
 
-    def update_contents(new_content = '{}')
+    def update_contents(new_content = {})
+      raise ArgumentError if new_content.is_a?(String)
       @content = new_content
     end
 
     def write
-      if source != @content
-        @storage.write(@relative_path, content)
-        @source = content
+      pretty = JSON.pretty_generate(@content)
+      if source.rstrip != pretty.rstrip
+        # Most editors add a trailing \n at the end of files. Here we
+        # try to maintain the convention.
+        eof = source.end_with?("\n") ? "\n" : ""
+        @storage.write(@relative_path, pretty + eof)
+        @source = pretty
       end
     end
 
diff --git a/test/json_file_test.rb b/test/json_file_test.rb
index 46478d65..0f0d139d 100644
--- a/test/json_file_test.rb
+++ b/test/json_file_test.rb
@@ -32,6 +32,15 @@ def test_parse_error_with_error
     assert_instance_of(JSON::ParserError, @json.parse_error)
   end
 
+  def test_write
+    storage = make_storage("a.json" => '{ "hello": "world" }')
+    expected = { hello: "friend" }
+    @json = ThemeCheck::JsonFile.new("a.json", storage)
+    @json.update_contents(expected)
+    @json.write
+    assert_equal(JSON.pretty_generate(expected), storage.read("a.json"))
+  end
+
   private
 
   def make_json_file(name, content)