From 25f13c4cef13311e97d65914afd2a5eec010e17e Mon Sep 17 00:00:00 2001
From: Shimpei Makimoto <makimoto@tsuyabu.in>
Date: Wed, 30 Oct 2013 18:55:52 +0900
Subject: [PATCH 1/2] Prevent irb from crashing when exception with nil
 backtrace is raised

---
 lib/irb.rb | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/lib/irb.rb b/lib/irb.rb
index 20390d2..a5208a1 100644
--- a/lib/irb.rb
+++ b/lib/irb.rb
@@ -499,7 +499,7 @@ def eval_input
           end
           if exc
             print exc.class, ": ", exc, "\n"
-            if exc.backtrace[0] =~ /irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
+            if exc.backtrace && exc.backtrace[0] =~ /irb(2)?(\/.*|-.*|\.rb)?:/ && exc.class.to_s !~ /^IRB/ &&
                 !(SyntaxError === exc)
               irb_bug = true
             else
@@ -509,16 +509,18 @@ def eval_input
             messages = []
             lasts = []
             levels = 0
-            for m in exc.backtrace
-              m = @context.workspace.filter_backtrace(m) unless irb_bug
-              if m
-                if messages.size < @context.back_trace_limit
-                  messages.push "\tfrom "+m
-                else
-                  lasts.push "\tfrom "+m
-                  if lasts.size > @context.back_trace_limit
-                    lasts.shift
-                    levels += 1
+            if exc.backtrace
+              for m in exc.backtrace
+                m = @context.workspace.filter_backtrace(m) unless irb_bug
+                if m
+                  if messages.size < @context.back_trace_limit
+                    messages.push "\tfrom "+m
+                  else
+                    lasts.push "\tfrom "+m
+                    if lasts.size > @context.back_trace_limit
+                      lasts.shift
+                      levels += 1
+                    end
                   end
                 end
               end
-- 
1.8.4


From ae3cc8659b35097634f2b583c2fed38cc768bd13 Mon Sep 17 00:00:00 2001
From: Shimpei Makimoto <makimoto@tsuyabu.in>
Date: Wed, 30 Oct 2013 23:09:55 +0900
Subject: [PATCH 2/2] Add test_raise_no_bactrace_exception

---
 test/irb/test_raise_no_backtrace_exception.rb | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 test/irb/test_raise_no_backtrace_exception.rb

diff --git a/test/irb/test_raise_no_backtrace_exception.rb b/test/irb/test_raise_no_backtrace_exception.rb
new file mode 100644
index 0000000..e8204d7
--- /dev/null
+++ b/test/irb/test_raise_no_backtrace_exception.rb
@@ -0,0 +1,14 @@
+require 'test/unit'
+require_relative '../ruby/envutil'
+
+module TestIRB
+  class TestRaiseNoBacktraceException < Test::Unit::TestCase
+    def test_raise_exception
+      status = assert_in_out_err(%w[-rirb -e IRB.start(__FILE__) -- -f --], <<-IRB, /Exception: foo/, [])
+      e = Exception.new("foo")
+      def e.backtrace; nil; end
+      raise e
+IRB
+    end
+  end
+end
-- 
1.8.4