feat: add reset method for kernel tracer patches

Implemented KernelPatches.reset in both recorder gems to uninstall
all active tracers and restore original Kernel methods. Tests now use
this helper in setup and teardown. Added dedicated test verifying that
reset leaves no tracers installed and methods restored.

Author: zah

.agents/tasks/2025/06/29-2257-kernel-reset

@@ -0,0 +1 @@
+Implement KernelPatches.reset to uninstall all tracers and update tests

gems/codetracer-pure-ruby-recorder/lib/codetracer/kernel_patches.rb

@@ -57,5 +57,12 @@ def self.uninstall(tracer)
         end
       end
     end
+
+    # Uninstall all active tracers and restore the original Kernel methods.
+    def self.reset
+      @@tracers.dup.each do |tracer|
+        uninstall(tracer)
+      end
+    end
   end
 end

gems/codetracer-ruby-recorder/lib/codetracer/kernel_patches.rb

@@ -57,5 +57,12 @@ def self.uninstall(tracer)
         end
       end
     end
+
+    # Uninstall all active tracers and restore the original Kernel methods.
+    def self.reset
+      @@tracers.dup.each do |tracer|
+        uninstall(tracer)
+      end
+    end
   end
 end

test/test_kernel_patches.rb

@@ -24,21 +24,11 @@ class TestKernelPatches < Minitest::Test
   def setup
     @tracer1 = MockTracer.new("tracer1")
     @tracer2 = MockTracer.new("tracer2")
-    # Ensure a clean state before each test by attempting to clear any existing tracers
-    # This is a bit of a hack, ideally KernelPatches would offer a reset or more direct access
-    current_tracers = CodeTracer::KernelPatches.class_variable_get(:@@tracers).dup
-    current_tracers.each do |tracer|
-      CodeTracer::KernelPatches.uninstall(tracer)
-    end
+    CodeTracer::KernelPatches.reset
   end
 
   def teardown
-    # Ensure all tracers are uninstalled after each test
-    current_tracers = CodeTracer::KernelPatches.class_variable_get(:@@tracers).dup
-    current_tracers.each do |tracer|
-      CodeTracer::KernelPatches.uninstall(tracer)
-    end
-    # Verify that original methods are restored if no tracers are left
+    CodeTracer::KernelPatches.reset
     assert_empty CodeTracer::KernelPatches.class_variable_get(:@@tracers), "Tracers should be empty after teardown"
   end
 
@@ -116,6 +106,24 @@ def test_restoration_of_original_methods
     assert_empty @tracer1.events, "Tracer should not record events after being uninstalled and patches removed"
   end
 
+  def test_reset_removes_all_tracers_and_restores_methods
+    CodeTracer::KernelPatches.install(@tracer1)
+    CodeTracer::KernelPatches.install(@tracer2)
+
+    CodeTracer::KernelPatches.reset
+
+    assert_empty CodeTracer::KernelPatches.class_variable_get(:@@tracers), "No tracers should remain after reset"
+
+    p 'after reset'
+
+    assert_empty @tracer1.events, "Tracer1 should not record after reset"
+    assert_empty @tracer2.events, "Tracer2 should not record after reset"
+
+    assert_equal Kernel.instance_method(:codetracer_original_p), Kernel.instance_method(:p)
+    assert_equal Kernel.instance_method(:codetracer_original_puts), Kernel.instance_method(:puts)
+    assert_equal Kernel.instance_method(:codetracer_original_print), Kernel.instance_method(:print)
+  end
+
   def test_correct_event_arguments
     CodeTracer::KernelPatches.install(@tracer1)