lib/irb.rb in irb-1.9.1 vs lib/irb.rb in irb-1.10.0

@@ -18,10 +18,11 @@
 require_relative "irb/color"
 
 require_relative "irb/version"
 require_relative "irb/easter-egg"
 require_relative "irb/debug"
+require_relative "irb/pager"
 
 # IRB stands for "interactive Ruby" and is a tool to interactively execute Ruby
 # expressions read from the standard input.
 #
 # The +irb+ command from your shell will start the interpreter.
@@ -695,57 +696,61 @@
       end while nil
       dst
     end
 
     def handle_exception(exc)
-      if exc.backtrace && exc.backtrace[0] =~ /\/irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
+      if exc.backtrace[0] =~ /\/irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
          !(SyntaxError === exc) && !(EncodingError === exc)
         # The backtrace of invalid encoding hash (ex. {"\xAE": 1}) raises EncodingError without lineno.
         irb_bug = true
       else
         irb_bug = false
       end
 
-      if exc.backtrace
-        order = nil
-        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
-          end
-        else # '3.0.0' <= RUBY_VERSION
+      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
         end
-        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.+$\n)+)/)  { |m|
-          case order
-          when :top
-            lines = m.split("\n")
-          when :bottom
-            lines = m.split("\n").reverse
+      else # '3.0.0' <= RUBY_VERSION
+        message = exc.full_message(order: :top)
+        order = :top
+      end
+      message = convert_invalid_byte_sequence(message, exc.message.encoding)
+      message = encode_with_invalid_byte_sequence(message, IRB.conf[:LC_MESSAGES].encoding) unless message.encoding.to_s.casecmp?(IRB.conf[:LC_MESSAGES].encoding.to_s)
+      message = message.gsub(/((?:^\t.+$\n)+)/) { |m|
+        case order
+        when :top
+          lines = m.split("\n")
+        when :bottom
+          lines = m.split("\n").reverse
+        end
+        unless irb_bug
+          lines = lines.map { |l| @context.workspace.filter_backtrace(l) }.compact
+          if lines.size > @context.back_trace_limit
+            omit = lines.size - @context.back_trace_limit
+            lines = lines[0..(@context.back_trace_limit - 1)]
+            lines << "\t... %d levels..." % omit
           end
-          unless irb_bug
-            lines = lines.map { |l| @context.workspace.filter_backtrace(l) }.compact
-            if lines.size > @context.back_trace_limit
-              omit = lines.size - @context.back_trace_limit
-              lines = lines[0..(@context.back_trace_limit - 1)]
-              lines << "\t... %d levels..." % omit
-            end
-          end
-          lines = lines.reverse if order == :bottom
-          lines.map{ |l| l + "\n" }.join
-        }
-        # The "<top (required)>" in "(irb)" may be the top level of IRB so imitate the main object.
-        message = message.gsub(/\(irb\):(?<num>\d+):in `<(?<frame>top \(required\))>'/)  { "(irb):#{$~[:num]}:in `<main>'" }
-        puts message
+        end
+        lines = lines.reverse if order == :bottom
+        lines.map{ |l| l + "\n" }.join
+      }
+      # The "<top (required)>" in "(irb)" may be the top level of IRB so imitate the main object.
+      message = message.gsub(/\(irb\):(?<num>\d+):in `<(?<frame>top \(required\))>'/) { "(irb):#{$~[:num]}:in `<main>'" }
+      puts message
+      puts 'Maybe IRB bug!' if irb_bug
+    rescue Exception => handler_exc
+      begin
+        puts exc.inspect
+        puts "backtraces are hidden because #{handler_exc} was raised when processing them"
+      rescue Exception
+        puts 'Uninspectable exception occurred'
       end
-      print "Maybe IRB bug!\n" if irb_bug
     end
 
     # Evaluates the given block using the given +path+ as the Context#irb_path
     # and +name+ as the Context#irb_name.
     #
@@ -853,15 +858,16 @@
             str = "%s..." % lines.first
             str += "\e[0m" if Color.colorable?
           end
         end
       end
+
       if multiline_p && @context.newline_before_multiline_output?
-        printf @context.return_format, "\n#{str}"
-      else
-        printf @context.return_format, str
+        str = "\n" + str
       end
+
+      Pager.page_content(format(@context.return_format, str), retain_content: true)
     end
 
     # Outputs the local variables to this current session, including
     # #signal_status and #context, using IRB::Locale.
     def inspect
@@ -924,12 +930,14 @@
       format.gsub(/%([0-9]+)?([a-zA-Z])/) do
         case $2
         when "N"
           @context.irb_name
         when "m"
-          truncate_prompt_main(@context.main.to_s)
+          main_str = @context.main.to_s rescue "!#{$!.class}"
+          truncate_prompt_main(main_str)
         when "M"
-          truncate_prompt_main(@context.main.inspect)
+          main_str = @context.main.inspect rescue "!#{$!.class}"
+          truncate_prompt_main(main_str)
         when "l"
           ltype
         when "i"
           if indent < 0
             if $1