From 3463724750c96e4f7d24d58b2d34bd1650df239e Mon Sep 17 00:00:00 2001
From: Jay Hayes <ur@iamvery.com>
Date: Tue, 17 Sep 2019 10:25:54 -0500
Subject: [PATCH 1/3] Add failing example illustrating behavior of
 MismatchError in bare rescue

---
 test/scientist/experiment_test.rb | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/test/scientist/experiment_test.rb b/test/scientist/experiment_test.rb
index e12ef37..8154c58 100644
--- a/test/scientist/experiment_test.rb
+++ b/test/scientist/experiment_test.rb
@@ -444,6 +444,18 @@ def @ex.raised(op, exception)
       assert_raises(Scientist::Experiment::MismatchError) { @ex.run }
     end
 
+    it "allows MismatchError to bubble up through bare rescues" do
+      Fake.raise_on_mismatches = true
+      @ex.use { "control" }
+      @ex.try { "candidate" }
+      runner = -> do
+        @ex.run
+      rescue
+        # StandardError handled
+      end
+      assert_raises(Scientist::Experiment::MismatchError) { runner.call }
+    end
+
     describe "#raise_on_mismatches?" do
       it "raises when there is a mismatch if the experiment instance's raise on mismatches is enabled" do
         Fake.raise_on_mismatches = false

From 0b76afccfda17ce927522225903c1b0a559d8888 Mon Sep 17 00:00:00 2001
From: Jay Hayes <ur@iamvery.com>
Date: Mon, 16 Sep 2019 15:57:37 -0500
Subject: [PATCH 2/3] Make MismatchError a base Exception

This allows mismatches to avoid being caught by bare rescue's which
should help make them more visible in the face of code which chooses to
use such a general rescue strategy.
---
 lib/scientist/experiment.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/scientist/experiment.rb b/lib/scientist/experiment.rb
index 53f2ae0..e824268 100644
--- a/lib/scientist/experiment.rb
+++ b/lib/scientist/experiment.rb
@@ -18,7 +18,7 @@ def self.new(name)
   end
 
   # A mismatch, raised when raise_on_mismatches is enabled.
-  class MismatchError < StandardError
+  class MismatchError < Exception
     attr_reader :name, :result
 
     def initialize(name, result)

From ad48edc8dd6678ae2e48a624c2c01a5d64dea77d Mon Sep 17 00:00:00 2001
From: Jay Hayes <ur@iamvery.com>
Date: Tue, 17 Sep 2019 10:31:34 -0500
Subject: [PATCH 3/3] Fix begin/rescue syntax for older rubies

---
 test/scientist/experiment_test.rb | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/test/scientist/experiment_test.rb b/test/scientist/experiment_test.rb
index 8154c58..7588286 100644
--- a/test/scientist/experiment_test.rb
+++ b/test/scientist/experiment_test.rb
@@ -448,11 +448,13 @@ def @ex.raised(op, exception)
       Fake.raise_on_mismatches = true
       @ex.use { "control" }
       @ex.try { "candidate" }
-      runner = -> do
-        @ex.run
-      rescue
-        # StandardError handled
-      end
+      runner = -> {
+        begin
+          @ex.run
+        rescue
+          # StandardError handled
+        end
+      }
       assert_raises(Scientist::Experiment::MismatchError) { runner.call }
     end