[GR-47035] JT: look at ruby_home/release if no graalvm_home

PullRequest: truffleruby/3911

Author: eregon

spec/truffle/interop/add_to_classpath_spec.rb

@@ -12,7 +12,9 @@
   describe "Java.add_to_classpath" do
     before :all do
       jar_dir = File.expand_path(File.dirname(__FILE__)) + '/fixtures/examplejar'
-      bin_dir = TruffleRuby.graalvm_home + '/bin'
+      java_home = Truffle::System.get_java_property('java.home')
+      raise "#{java_home} does not exist" unless Dir.exist?(java_home)
+      bin_dir = "#{java_home}/bin"
       Dir.chdir(jar_dir) do
         system("#{bin_dir}/javac org/truffleruby/examplejar/Example.java")
         system("#{bin_dir}/jar cf example.jar org/truffleruby/examplejar/Example.class")

tool/jt.rb

@@ -331,7 +331,7 @@ def truffleruby_compiler?
     return @truffleruby_compiler = true if truffleruby_native_built?
 
     # Detect if the compiler is present by reading the $graalvm_home/release file
-    @truffleruby_compiler = File.readlines("#{graalvm_home}/release").grep(/^COMMIT_INFO=/).any? do |line|
+    @truffleruby_compiler = File.readlines("#{graalvm_home || ruby_home}/release").grep(/^COMMIT_INFO=/).any? do |line|
       line.include?('"compiler":') || line.include?("'compiler':")
     end
   end