Issue#3485: Fix corruption of run_context when guard interpreters are executedadamedx/3485-run_context_corruption

3 files changed, 13 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6c0bbb0677..7ddb91ab3d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## Unreleased
+* [pr#3497](https://github.com/chef/chef/pull/3497): Issue 3485: Corruption of node's run\_context when non-default guard\_interpreter is evaluated
 * [**Yukihiko SAWANOBORI**](https://github.com/sawanoboly): Pass name by
   knife cil attribute [pr#3195](https://github.com/chef/chef/pull/3195)
 * [**Torben Knerr**](https://github.com/tknerr):
diff --git a/lib/chef/guard_interpreter/resource_guard_interpreter.rb b/lib/chef/guard_interpreter/resource_guard_interpreter.rb
index 1e2a534c18..d4b386a15a 100644
--- a/lib/chef/guard_interpreter/resource_guard_interpreter.rb
+++ b/lib/chef/guard_interpreter/resource_guard_interpreter.rb
@@ -92,8 +92,11 @@ class Chef
           raise ArgumentError, "Specified guard interpreter class #{resource_class} must be a kind of Chef::Resource::Execute resource"
         end
 
+        # Duplicate the node below because the new RunContext
+        # overwrites the state of Node instances passed to it.
+        # See https://github.com/chef/chef/issues/3485.
         empty_events = Chef::EventDispatch::Dispatcher.new
-        anonymous_run_context = Chef::RunContext.new(parent_resource.node, {}, empty_events)
+        anonymous_run_context = Chef::RunContext.new(parent_resource.node.dup, {}, empty_events)
         interpreter_resource = resource_class.new('Guard resource', anonymous_run_context)
         interpreter_resource.is_guard_interpreter = true
 
diff --git a/spec/unit/guard_interpreter/resource_guard_interpreter_spec.rb b/spec/unit/guard_interpreter/resource_guard_interpreter_spec.rb
index 02e4eb2fae..acf1b15fd8 100644
--- a/spec/unit/guard_interpreter/resource_guard_interpreter_spec.rb
+++ b/spec/unit/guard_interpreter/resource_guard_interpreter_spec.rb
@@ -84,6 +84,14 @@ describe Chef::GuardInterpreter::ResourceGuardInterpreter do
       expect(guard_interpreter.evaluate).to eq(true)
     end
 
+    it "does not corrupt the run_context of the node" do
+      node_run_context_before_guard_execution = parent_resource.run_context
+      expect(node_run_context_before_guard_execution.object_id).to eq(parent_resource.node.run_context.object_id)
+      guard_interpreter.evaluate
+      node_run_context_after_guard_execution = parent_resource.run_context
+      expect(node_run_context_after_guard_execution.object_id).to eq(parent_resource.node.run_context.object_id)
+    end
+
     describe "script command opts switch" do
       let(:command_opts) { {} }
       let(:guard_interpreter) { Chef::GuardInterpreter::ResourceGuardInterpreter.new(parent_resource, "exit 0", command_opts) }