Extract version number from the source

"requiring version.rb" strategy has some issues.

- cannot work when cross-compiling
- often introduces wrong namespace
- must know the superclasses
- costs at each runtime than at build-time

etc.

1 files changed, 9 insertions, 6 deletions

diff --git a/lib/delegate/delegate.gemspec b/lib/delegate/delegate.gemspec
index 63b00c5894..bf7dd6600d 100644
--- a/lib/delegate/delegate.gemspec
+++ b/lib/delegate/delegate.gemspec
@@ -1,12 +1,15 @@
-begin
-  require_relative "lib/delegate/version"
-rescue LoadError # Fallback to load version file in ruby core repository
-  require_relative "version"
+# frozen_string_literal: true
+
+name = File.basename(__FILE__, ".gemspec")
+version = ["lib", Array.new(name.count("-")+1, "..").join("/")].find do |dir|
+  break File.foreach(File.join(__dir__, dir, "#{name.tr('-', '/')}.rb")) do |line|
+    /^\s*VERSION\s*=\s*"(.*)"/ =~ line and break $1
+  end rescue nil
 end
 
 Gem::Specification.new do |spec|
-  spec.name          = "delegate"
-  spec.version       = Delegator::VERSION
+  spec.name          = name
+  spec.version       = version
   spec.authors       = ["Yukihiro Matsumoto"]
   spec.email         = ["matz@ruby-lang.org"]