Add path option to WatchBreakpoint

Author: st0012

lib/debug/breakpoint.rb

@@ -337,7 +337,7 @@ def to_s
   end
 
   class WatchIVarBreakpoint < Breakpoint
-    def initialize ivar, object, current, cond: nil, command: nil
+    def initialize ivar, object, current, cond: nil, command: nil, path: nil
       @ivar = ivar.to_sym
       @object = object
       @key = [:watch, object.object_id, @ivar].freeze
@@ -346,6 +346,7 @@ def initialize ivar, object, current, cond: nil, command: nil
 
       @cond = cond
       @command = command
+      @path = path
       super()
     end
 
@@ -371,6 +372,7 @@ def setup
       @tp = TracePoint.new(:line, :return, :b_return){|tp|
         next if tp.path.start_with? __dir__
         next if tp.path.start_with? '<internal:'
+        next if @path && !tp.path.match?(@path)
 
         watch_eval
       }

lib/debug/session.rb

@@ -1304,8 +1304,9 @@ def repl_add_watch_breakpoint arg
       expr = parse_break arg.strip
       cond = expr[:if]
       cmd = ['watch', expr[:pre], expr[:do]] if expr[:pre] || expr[:do]
+      path = Regexp.compile(expr[:path]) if expr[:path]
 
-      @tc << [:breakpoint, :watch, expr[:sig], cond, cmd]
+      @tc << [:breakpoint, :watch, expr[:sig], cond, cmd, path]
     end
 
     def add_catch_breakpoint pat

lib/debug/thread_client.rb

@@ -644,8 +644,8 @@ def make_breakpoint args
 
         bp
       when :watch
-        ivar, object, result, cond, command = args[1..]
-        WatchIVarBreakpoint.new(ivar, object, result, cond: cond, command: command)
+        ivar, object, result, cond, command, path = args[1..]
+        WatchIVarBreakpoint.new(ivar, object, result, cond: cond, command: command, path: path)
       else
         raise "unknown breakpoint: #{args}"
       end
@@ -888,7 +888,7 @@ def wait_next_action_
             bp = make_breakpoint args
             event! :result, :method_breakpoint, bp
           when :watch
-            ivar, cond, command = args[1..]
+            ivar, cond, command, path = args[1..]
             result = frame_eval(ivar)
 
             if @success_last_eval
@@ -898,7 +898,7 @@ def wait_next_action_
                 else
                   current_frame.self
                 end
-              bp = make_breakpoint [:watch, ivar, object, result, cond, command]
+              bp = make_breakpoint [:watch, ivar, object, result, cond, command, path]
               event! :result, :watch_breakpoint, bp
             else
               event! :result, nil

test/debug/watch_test.rb

@@ -103,5 +103,43 @@ def test_condition_is_evaluated_in_the_watched_object
         end
       end
     end
+
+    class PathOptionTest < TestCase
+      def extra_file
+        <<~RUBY
+        STUDENT.age = 25
+        _ = 1 # for the debugger to stop
+        RUBY
+      end
+
+      def program(extra_file_path)
+        <<~RUBY
+         1| class Student
+         2|   attr_accessor :age
+         3|
+         4|   def initialize
+         5|     binding.b(do: "watch @age path: #{extra_file_path}")
+         6|   end
+         7| end
+         8|
+         9| STUDENT = Student.new
+        10|
+        11| load "#{extra_file_path}"
+        12|
+        13| STUDENT.age = 30
+        14| _ = 1
+        RUBY
+      end
+
+      def test_watch_only_stops_when_path_matches
+        with_extra_tempfile do |extra_file|
+          debug_code(program(extra_file.path)) do
+            type 'c'
+            assert_line_text(/@age =  -> 25/)
+            type 'c'
+          end
+        end
+      end
+    end
   end
 end