Merge pull request #719 from casperisfine/fix-erb-version-check

Better ERB keyword argument check

CHANGELOG.md

@@ -4,6 +4,7 @@ Get upgrade notes from Sprockets 3.x to 4.x at https://github.com/rails/sprocket
 
 ## Master
 
+- Better detect the ERB version to avoid deprecation warnings. [#719](https://github.com/rails/sprockets/pull/719)
 - Allow assets already fingerprinted to be served through `Sprockets::Server`
 - Do not fingerprint files that already contain a valid digest in their name
 - Remove remaining support for Ruby < 2.4.[#672](https://github.com/rails/sprockets/pull/672)

lib/sprockets/erb_processor.rb

@@ -18,8 +18,7 @@ def initialize(&block)
   end
 
   def call(input)
-    match = ERB.version.match(/\Aerb\.rb \[(?<version>[^ ]+) /)
-    if match && match[:version] >= "2.2.0" # Ruby 2.6+
+    if keyword_constructor? # Ruby 2.6+
       engine = ::ERB.new(input[:data], trim_mode: '<>')
     else
       engine = ::ERB.new(input[:data], nil, '<>')
@@ -34,4 +33,11 @@ def call(input)
     data = engine.result(context.instance_eval('binding'))
     context.metadata.merge(data: data)
   end
+
+  private
+
+  def keyword_constructor?
+    return @keyword_constructor if defined? @keyword_constructor
+    @keyword_constructor = ::ERB.instance_method(:initialize).parameters.include?([:key, :trim_mode])
+  end
 end