Fix BACK_TRACE_LIMIT logic

aycabta · aycabta · commit 30dc5d43fe7a · 2021-01-08T04:51:28.000+09:00
diff --git a/lib/irb.rb b/lib/irb.rb
@@ -640,8 +640,8 @@ def handle_exception(exc)
             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[0..(@context.back_trace_limit - 1)]
-              lines << '... %d levels...' % omit
+              lines = lines[0..(@context.back_trace_limit - 1)]
+              lines << "\t... %d levels..." % omit
             end
           end
           lines = lines.reverse if order == :bottom
diff --git a/test/irb/test_context.rb b/test/irb/test_context.rb
@@ -469,5 +469,71 @@ def test_eval_input_with_invalid_byte_sequence_exception
     ensure
       $VERBOSE = verbose
     end
+
+    def test_eval_input_with_long_exception
+      skip if RUBY_ENGINE == 'truffleruby'
+      verbose, $VERBOSE = $VERBOSE, nil
+      nesting = 20
+      generated_code = ''
+      nesting.times do |i|
+        generated_code << "def a#{i}() a#{i + 1}; end; "
+      end
+      generated_code << "def a#{nesting}() raise; end; a0\n"
+      input = TestInputMethod.new([
+        generated_code
+      ])
+      irb = IRB::Irb.new(IRB::WorkSpace.new(Object.new), input)
+      out, err = capture_output do
+        irb.eval_input
+      end
+      assert_empty err
+      if '2.5.0' <= RUBY_VERSION && RUBY_VERSION < '3.0.0'
+        expected = [
+          :*, /Traceback \(most recent call last\):\n/,
+          :*, /\t... 5 levels...\n/,
+          :*, /\t16: from \(irb\):1:in `a4'\n/,
+          :*, /\t15: from \(irb\):1:in `a5'\n/,
+          :*, /\t14: from \(irb\):1:in `a6'\n/,
+          :*, /\t13: from \(irb\):1:in `a7'\n/,
+          :*, /\t12: from \(irb\):1:in `a8'\n/,
+          :*, /\t11: from \(irb\):1:in `a9'\n/,
+          :*, /\t10: from \(irb\):1:in `a10'\n/,
+          :*, /\t 9: from \(irb\):1:in `a11'\n/,
+          :*, /\t 8: from \(irb\):1:in `a12'\n/,
+          :*, /\t 7: from \(irb\):1:in `a13'\n/,
+          :*, /\t 6: from \(irb\):1:in `a14'\n/,
+          :*, /\t 5: from \(irb\):1:in `a15'\n/,
+          :*, /\t 4: from \(irb\):1:in `a16'\n/,
+          :*, /\t 3: from \(irb\):1:in `a17'\n/,
+          :*, /\t 2: from \(irb\):1:in `a18'\n/,
+          :*, /\t 1: from \(irb\):1:in `a19'\n/,
+          :*, /\(irb\):1:in `a20': unhandled exception\n/,
+        ]
+      else
+        expected = [
+          :*, /\(irb\):1:in `a20': unhandled exception\n/,
+          :*, /\tfrom \(irb\):1:in `a19'\n/,
+          :*, /\tfrom \(irb\):1:in `a18'\n/,
+          :*, /\tfrom \(irb\):1:in `a17'\n/,
+          :*, /\tfrom \(irb\):1:in `a16'\n/,
+          :*, /\tfrom \(irb\):1:in `a15'\n/,
+          :*, /\tfrom \(irb\):1:in `a14'\n/,
+          :*, /\tfrom \(irb\):1:in `a13'\n/,
+          :*, /\tfrom \(irb\):1:in `a12'\n/,
+          :*, /\tfrom \(irb\):1:in `a11'\n/,
+          :*, /\tfrom \(irb\):1:in `a10'\n/,
+          :*, /\tfrom \(irb\):1:in `a9'\n/,
+          :*, /\tfrom \(irb\):1:in `a8'\n/,
+          :*, /\tfrom \(irb\):1:in `a7'\n/,
+          :*, /\tfrom \(irb\):1:in `a6'\n/,
+          :*, /\tfrom \(irb\):1:in `a5'\n/,
+          :*, /\tfrom \(irb\):1:in `a4'\n/,
+          :*, /\t... 5 levels...\n/,
+        ]
+      end
+      assert_pattern_list(expected, out)
+    ensure
+      $VERBOSE = verbose
+    end
   end
 end
