[ruby/irb] Fix usage of tracer gem and add tests

(https://github.com/ruby/irb/pull/857)

The new tests are skipped when ruby below 3.1, as it was a default gem on it, and in a version we do not support.

This also move definition of `use_tracer` to module Context instead of monkey patch.

https://github.com/ruby/irb/commit/08834fbd5f

3 files changed, 12 insertions, 54 deletions

diff --git a/lib/irb/context.rb b/lib/irb/context.rb
index ac61b765c0..5b8791c3ba 100644
--- a/lib/irb/context.rb
+++ b/lib/irb/context.rb
@@ -161,6 +161,11 @@ module IRB
 
     private_constant :KEYWORD_ALIASES
 
+    def use_tracer=(val)
+      require_relative "ext/tracer"
+      @use_tracer = val
+    end
+
     private def build_completor
       completor_type = IRB.conf[:COMPLETOR]
       case completor_type
diff --git a/lib/irb/ext/tracer.rb b/lib/irb/ext/tracer.rb
index 3eaeb70ef2..53b2e62245 100644
--- a/lib/irb/ext/tracer.rb
+++ b/lib/irb/ext/tracer.rb
@@ -3,76 +3,30 @@
 #   irb/lib/tracer.rb -
 #   	by Keiju ISHITSUKA([email protected])
 #
-
+# Loading the gem "tracer" will cause it to extend IRB commands with:
+# https://github.com/ruby/tracer/blob/v0.2.2/lib/tracer/irb.rb
 begin
   require "tracer"
 rescue LoadError
   $stderr.puts "Tracer extension of IRB is enabled but tracer gem wasn't found."
-  module IRB
-    class Context
-      def use_tracer=(opt)
-        # do nothing
-      end
-    end
-  end
   return # This is about to disable loading below
 end
 
 module IRB
-
-  # initialize tracing function
-  def IRB.initialize_tracer
-    Tracer.verbose = false
-    Tracer.add_filter {
-      |event, file, line, id, binding, *rests|
-      /^#{Regexp.quote(@CONF[:IRB_LIB_PATH])}/ !~ file and
-        File::basename(file) != "irb.rb"
-    }
-  end
-
-  class Context
-    # Whether Tracer is used when evaluating statements in this context.
-    #
-    # See +lib/tracer.rb+ for more information.
-    attr_reader :use_tracer
-    alias use_tracer? use_tracer
-
-    # Sets whether or not to use the Tracer library when evaluating statements
-    # in this context.
-    #
-    # See +lib/tracer.rb+ for more information.
-    def use_tracer=(opt)
-      if opt
-        Tracer.set_get_line_procs(@irb_path) {
-          |line_no, *rests|
-          @io.line(line_no)
-        }
-      elsif !opt && @use_tracer
-        Tracer.off
-      end
-      @use_tracer=opt
-    end
-  end
-
   class WorkSpace
     alias __evaluate__ evaluate
     # Evaluate the context of this workspace and use the Tracer library to
     # output the exact lines of code are being executed in chronological order.
     #
-    # See +lib/tracer.rb+ for more information.
-    def evaluate(context, statements, file = nil, line = nil)
-      if context.use_tracer? && file != nil && line != nil
-        Tracer.on
-        begin
+    # See https://github.com/ruby/tracer for more information.
+    def evaluate(statements, file = __FILE__, line = __LINE__)
+      if IRB.conf[:USE_TRACER] == true
+        CallTracer.new(colorize: Color.colorable?).start do
           __evaluate__(statements, file, line)
-        ensure
-          Tracer.off
         end
       else
-        __evaluate__(statements, file || __FILE__, line || __LINE__)
+        __evaluate__(statements, file, line)
       end
     end
   end
-
-  IRB.initialize_tracer
 end
diff --git a/lib/irb/extend-command.rb b/lib/irb/extend-command.rb
index 69d83080df..91ca96e91a 100644
--- a/lib/irb/extend-command.rb
+++ b/lib/irb/extend-command.rb
@@ -317,7 +317,6 @@ module IRB # :nodoc:
 
     @EXTEND_COMMANDS = [
       [:eval_history=, "ext/eval_history.rb"],
-      [:use_tracer=, "ext/tracer.rb"],
       [:use_loader=, "ext/use-loader.rb"],
     ]