Fix issue with Kernel#` when invalid UTF-8 bytes are given

Author: bjfish

CHANGELOG.md

@@ -9,6 +9,7 @@ Bug fixes:
 * Fix error message when the method name is not a Symbol or String for `Kernel#respond_to?` (#2132, @ssnickolay)
 * Fixed setting of special variables in enumerators and enumerables (#1484).
 * Fixed return value of `Enumerable#count` and `Enumerable#uniq` with multiple yielded arguments (#2145, @LillianZ).
+* Fixed issue with ``Kernel#` `` when invalid UTF-8 given (#2118).
 
 Compatibility:
 

spec/ruby/core/kernel/backtick_spec.rb

@@ -35,6 +35,10 @@
     -> { `nonexistent_command` }.should raise_error(Errno::ENOENT)
   end
 
+  it "handles invalid UTF-8 bytes in command" do
+    `echo "testing\xC2 a non UTF-8 string"`.should == "testing\xC2 a non UTF-8 string\n"
+  end
+
   platform_is_not :windows do
     it "sets $? to the exit status of the executed sub-process" do
       ip = 'world'

spec/tags/core/kernel/backtick_tags.txt

@@ -4,3 +4,4 @@ slow:Kernel#` produces a String in the default external encoding
 slow:Kernel#` raises an Errno::ENOENT if the command is not executable
 slow:Kernel#` sets $? to the exit status of the executed sub-process
 slow:Kernel.` tries to convert the given argument to String using #to_str
+slow:Kernel#` handles invalid UTF-8 bytes in command

src/main/ruby/truffleruby/core/truffle/process_operations.rb

@@ -89,7 +89,7 @@ module ProcessOperations
     ]
     # A simplified version of Regexp.new("[#{SHELL_META_CHARS.map { |c| Regexp.escape(c) }.join}]")
     # to avoid running too much code during initialization
-    SHELL_META_CHAR_PATTERN = /[*?{}\[\]<>()~&|\\$;'`"\n#=%]/
+    SHELL_META_CHAR_PATTERN = /[*?{}\[\]<>()~&|\\$;'`"\n#=%]/n
 
     def self.exec(*args)
       exe = Execute.new
@@ -543,7 +543,7 @@ def exec
       end
 
       def should_use_shell?(command)
-        command.match?(SHELL_META_CHAR_PATTERN)
+        command.b.match?(SHELL_META_CHAR_PATTERN)
       end
 
       def should_search_path?(command)