Fallback to non-colored inspect when coloring takes too long

lib/irb/context.rb

@@ -61,6 +61,8 @@ def initialize(irb, workspace = nil, input_method = nil)
       @io = nil
 
       self.inspect_mode = IRB.conf[:INSPECT_MODE]
+      @inspect_coloring_timeout = IRB.conf[:INSPECT_COLORING_TIMEOUT]
+
       self.use_tracer = IRB.conf[:USE_TRACER] if IRB.conf[:USE_TRACER]
       self.use_loader = IRB.conf[:USE_LOADER] if IRB.conf[:USE_LOADER]
       self.eval_history = IRB.conf[:EVAL_HISTORY] if IRB.conf[:EVAL_HISTORY]
@@ -251,6 +253,8 @@ def main
     attr_reader :use_autocomplete
     # A copy of the default <code>IRB.conf[:INSPECT_MODE]</code>
     attr_reader :inspect_mode
+    # Timeout (in seconds) for inspect coloring when INSPECT_MODE is :pp or :pretty_inspect.
+    attr_reader :inspect_coloring_timeout
 
     # A copy of the default <code>IRB.conf[:PROMPT_MODE]</code>
     attr_reader :prompt_mode

lib/irb/inspector.rb

@@ -112,8 +112,18 @@ def inspect_value(v)
   Inspector.def_inspector([:p, :inspect]){|v|
     Color.colorize_code(v.inspect, colorable: Color.colorable? && Color.inspect_colorable?(v))
   }
-  Inspector.def_inspector([true, :pp, :pretty_inspect], proc{require_relative "color_printer"}){|v|
-    IRB::ColorPrinter.pp(v, '').chomp
+  Inspector.def_inspector(
+    [true, :pp, :pretty_inspect],
+    proc{require "timeout"; require_relative "color_printer"; require_relative "pp_printer"}
+  ){|v|
+    begin
+      Timeout.timeout(IRB.conf.fetch(:INSPECT_COLORING_TIMEOUT, 2)) do
+        IRB::ColorPrinter.pp(v, '').chomp
+      end
+    rescue Timeout::Error
+      # Fall back to non-colored pp if coloring takes too long
+      IRB::PpPrinter.pp(v, '').chomp
+    end
   }
   Inspector.def_inspector([:yaml, :YAML], proc{require "yaml"}){|v|
     begin

lib/irb/pp_printer.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+require 'pp'
+
+module IRB
+  class PpPrinter < ::PP
+    METHOD_RESPOND_TO = Object.instance_method(:respond_to?)
+    METHOD_INSPECT = Object.instance_method(:inspect)
+
+    class << self
+      def pp(obj, out = $>, width = screen_width)
+        q = PpPrinter.new(out, width)
+        q.guard_inspect_key {q.pp obj}
+        q.flush
+        out << "\n"
+      end
+
+      private
+
+      def screen_width
+        Reline.get_screen_size.last
+      rescue Errno::EINVAL # in `winsize': Invalid argument - <STDIN>
+        79
+      end
+    end
+
+    def pp(obj)
+      if String === obj
+        # Avoid calling Ruby 2.4+ String#pretty_print that splits a string by "\n"
+        obj.inspect
+      elsif !METHOD_RESPOND_TO.bind(obj).call(:inspect)
+        text(METHOD_INSPECT.bind(obj).call)
+      else
+        super
+      end
+    end
+  end
+end