Don't rescue overzealously. Fixes #220

lib/pry.rb

@@ -59,6 +59,27 @@ class Pry
     proc { |target_self, _| "pry #{Pry.view_clip(target_self)}:#{Dir.pwd} * " }
   ]
 
+  # As a REPL, we often want to catch any unexpected exceptions that may have
+  # been raised; however we don't want to go overboard and prevent the user
+  # from exiting Pry when they want to.
+  module RescuableException
+    def self.===(exception)
+      case exception
+      # Catch when the user hits ^C (Interrupt < SignalException), and assume
+      # that they just wanted to stop the in-progress command (just like bash etc.)
+      when Interrupt
+        true
+      # Don't catch signals (particularly not SIGTERM) as these are unlikely to be
+      # intended for pry itself. We should also make sure that Kernel#exit works.
+      when SystemExit, SignalException
+        false
+      # All other exceptions will be caught.
+      else
+        true
+      end
+    end
+  end
+
 end
 
 require "method_source"

lib/pry/completion.rb

@@ -94,7 +94,7 @@ class Pry
           begin
             candidates = eval("#{receiver}.constants.collect{|m| m.to_s}", bind)
             candidates |= eval("#{receiver}.methods.collect{|m| m.to_s}", bind)
-          rescue Exception
+          rescue RescuableException
             candidates = []
           end
           candidates.grep(/^#{message}/).collect{|e| receiver + "::" + e}
@@ -114,7 +114,7 @@ class Pry
 
           begin
             candidates = eval(receiver, bind).methods.collect{|m| m.to_s}
-          rescue Exception
+          rescue RescuableException
             candidates = []
           end
           select_message(receiver, message, candidates)
@@ -126,7 +126,7 @@ class Pry
 
           begin
             candidates = eval(receiver, bind).methods.collect{|m| m.to_s}
-          rescue Exception
+          rescue RescuableException
             candidates = []
           end
           select_message(receiver, message, candidates)
@@ -149,7 +149,7 @@ class Pry
             # Foo::Bar.func
             begin
               candidates = eval("#{receiver}.methods", bind).collect{|m| m.to_s}
-            rescue Exception
+            rescue RescuableException
               candidates = []
             end
           else
@@ -158,7 +158,7 @@ class Pry
             ObjectSpace.each_object(Module){|m|
               begin
                 name = m.name.to_s
-              rescue Exception
+              rescue RescuableException
                 name = ""
               end
               next if name != "IRB::Context" and

lib/pry/pry_instance.rb

@@ -181,9 +181,7 @@ class Pry
 
     res = set_last_result(target.eval(code, Pry.eval_path, Pry.current_line), target)
     res
-  rescue SystemExit => e
-    exit
-  rescue Exception => e
+  rescue RescuableException => e
     set_last_exception(e, target)
   ensure
     update_input_history(code)

test/test_pry.rb

@@ -170,6 +170,12 @@ describe Pry do
         pry_tester.rep(o)
         was_called.should == true
       end
+
+      it 'should not try to catch intended exceptions' do
+        lambda { mock_pry("raise SystemExit") }.should.raise SystemExit
+        # SIGTERM
+        lambda { mock_pry("raise SignalException.new(15)") }.should.raise SignalException
+      end
     end
 
     describe "repl" do