Support IRB.conf[:BACKTRACE_FILTER]

lib/irb.rb

@@ -1242,27 +1242,33 @@ def handle_exception(exc)
         irb_bug = true
       else
         irb_bug = false
-        # This is mostly to make IRB work nicely with Rails console's backtrace filtering, which patches WorkSpace#filter_backtrace
-        # In such use case, we want to filter the exception's backtrace before its displayed through Exception#full_message
-        # And we clone the exception object in order to avoid mutating the original exception
-        # TODO: introduce better API to expose exception backtrace externally
-        backtrace = exc.backtrace.map { |l| @context.workspace.filter_backtrace(l) }.compact
+        # To support backtrace filtering while utilizing Exception#full_message, we need to clone
+        # the exception to avoid modifying the original exception's backtrace.
         exc = exc.clone
-        exc.set_backtrace(backtrace)
-      end
+        filtered_backtrace = exc.backtrace.map { |l| @context.workspace.filter_backtrace(l) }.compact
+        backtrace_filter = IRB.conf[:BACKTRACE_FILTER]
 
-      if RUBY_VERSION < '3.0.0'
-        if STDOUT.tty?
-          message = exc.full_message(order: :bottom)
-          order = :bottom
-        else
-          message = exc.full_message(order: :top)
-          order = :top
+        if backtrace_filter
+          if backtrace_filter.respond_to?(:call)
+            filtered_backtrace = backtrace_filter.call(filtered_backtrace)
+          else
+            warn "IRB.conf[:BACKTRACE_FILTER] #{backtrace_filter} should respond to `call` method"
+          end
         end
-      else # '3.0.0' <= RUBY_VERSION
-        message = exc.full_message(order: :top)
-        order = :top
+
+        exc.set_backtrace(filtered_backtrace)
       end
+
+      highlight = Color.colorable?
+
+      order =
+        if RUBY_VERSION < '3.0.0'
+          STDOUT.tty? ? :bottom : :top
+        else # '3.0.0' <= RUBY_VERSION
+          :top
+        end
+
+      message = exc.full_message(order: order, highlight: highlight)
       message = convert_invalid_byte_sequence(message, exc.message.encoding)
       message = encode_with_invalid_byte_sequence(message, IRB.conf[:LC_MESSAGES].encoding) unless message.encoding.to_s.casecmp?(IRB.conf[:LC_MESSAGES].encoding.to_s)
       message = message.gsub(/((?:^\t.+$\n)+)/) { |m|

test/irb/helper.rb

@@ -196,7 +196,7 @@ def type(command)
     end
 
     def write_ruby(program)
-      @ruby_file = Tempfile.create(%w{irb- .rb})
+      @ruby_file = Tempfile.create(%w{irbtest- .rb})
       @tmpfiles << @ruby_file
       @ruby_file.write(program)
       @ruby_file.close

test/irb/test_irb.rb

@@ -823,4 +823,95 @@ def build_irb
       IRB::Irb.new(workspace, TestInputMethod.new)
     end
   end
+
+  class BacktraceFilteringTest < TestIRB::IntegrationTestCase
+    def test_backtrace_filtering
+      write_ruby <<~'RUBY'
+        def foo
+          raise "error"
+        end
+
+        def bar
+          foo
+        end
+
+        binding.irb
+      RUBY
+
+      output = run_ruby_file do
+        type "bar"
+        type "exit"
+      end
+
+      assert_match(/irbtest-.*\.rb:2:in (`|'Object#)foo': error \(RuntimeError\)/, output)
+      frame_traces = output.split("\n").select { |line| line.strip.match?(/from /) }.map(&:strip)
+
+      expected_traces = if RUBY_VERSION >= "3.3.0"
+        [
+          /from .*\/irbtest-.*.rb:6:in (`|'Object#)bar'/,
+          /from .*\/irbtest-.*.rb\(irb\):1:in [`']<main>'/,
+          /from <internal:kernel>:\d+:in (`|'Kernel#)loop'/,
+          /from <internal:prelude>:\d+:in (`|'Binding#)irb'/,
+          /from .*\/irbtest-.*.rb:9:in [`']<main>'/
+        ]
+      else
+        [
+          /from .*\/irbtest-.*.rb:6:in (`|'Object#)bar'/,
+          /from .*\/irbtest-.*.rb\(irb\):1:in [`']<main>'/,
+          /from <internal:prelude>:\d+:in (`|'Binding#)irb'/,
+          /from .*\/irbtest-.*.rb:9:in [`']<main>'/
+        ]
+      end
+
+      expected_traces.reverse! if RUBY_VERSION < "3.0.0"
+
+      expected_traces.each_with_index do |expected_trace, index|
+        assert_match(expected_trace, frame_traces[index])
+      end
+    end
+
+    def test_backtrace_filtering_with_backtrace_filter
+      write_rc <<~'RUBY'
+        class TestBacktraceFilter
+          def self.call(backtrace)
+            backtrace.reject { |line| line.include?("internal") }
+          end
+        end
+
+        IRB.conf[:BACKTRACE_FILTER] = TestBacktraceFilter
+      RUBY
+
+      write_ruby <<~'RUBY'
+        def foo
+          raise "error"
+        end
+
+        def bar
+          foo
+        end
+
+        binding.irb
+      RUBY
+
+      output = run_ruby_file do
+        type "bar"
+        type "exit"
+      end
+
+      assert_match(/irbtest-.*\.rb:2:in (`|'Object#)foo': error \(RuntimeError\)/, output)
+      frame_traces = output.split("\n").select { |line| line.strip.match?(/from /) }.map(&:strip)
+
+      expected_traces = [
+        /from .*\/irbtest-.*.rb:6:in (`|'Object#)bar'/,
+        /from .*\/irbtest-.*.rb\(irb\):1:in [`']<main>'/,
+        /from .*\/irbtest-.*.rb:9:in [`']<main>'/
+      ]
+
+      expected_traces.reverse! if RUBY_VERSION < "3.0.0"
+
+      expected_traces.each_with_index do |expected_trace, index|
+        assert_match(expected_trace, frame_traces[index])
+      end
+    end
+  end
 end