From db2dea26fe8c5d22660b2269f8485fe4912ad94f Mon Sep 17 00:00:00 2001
From: Markus Schirp <mbj@schirp-dso.com>
Date: Wed, 10 Jan 2024 04:49:40 +0000
Subject: [PATCH] Add Ruby-3.3 Process.warmup

---
 Changelog.md                             | 11 ++++---
 lib/mutant/mutation/runner.rb            |  2 ++
 lib/mutant/world.rb                      |  4 +++
 spec/unit/mutant/mutation/runner_spec.rb | 14 ++++++++-
 spec/unit/mutant/world_spec.rb           | 39 ++++++++++++++++++++++++
 5 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/Changelog.md b/Changelog.md
index bac14f8ed..9499a5fff 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,12 +1,15 @@
 # v0.11.28
 
-* Fix CLI parsing issue where arguments given to `mutant environment` where silently ignored.
-  [#1416](https://github.com/mbj/mutant/pull/1416)
+* [#1416](https://github.com/mbj/mutant/pull/1416)
+  Fix CLI parsing issue where arguments given to `mutant environment` where silently ignored.
 
-* Change to report efficiency instead of overhead.
+* [#1415](https://github.com/mbj/mutant/pull/1415)
+  Change to report efficiency instead of overhead.
   Efficiency is defined by `killtime / runtime`.
 
-  [#1415](https://github.com/mbj/mutant/pull/1415)
+* [#1413](https://github.com/mbj/mutant/pull/1413)
+
+  Add `Process.warmup` optimization for ruby-3.3+ which yields a noticable speed improvement.
 
 # v0.11.27 2023-12-01
 
diff --git a/lib/mutant/mutation/runner.rb b/lib/mutant/mutation/runner.rb
index 701274f22..032615798 100644
--- a/lib/mutant/mutation/runner.rb
+++ b/lib/mutant/mutation/runner.rb
@@ -15,6 +15,8 @@ def self.call(env)
       def self.run_mutation_analysis(env)
         reporter = reporter(env)
 
+        env.world.process_warmup
+
         env
           .record(:analysis) { run_driver(reporter, async_driver(env)) }
           .tap { |result| env.record(:report) { reporter.report(result) } }
diff --git a/lib/mutant/world.rb b/lib/mutant/world.rb
index 2677735eb..398b9623a 100644
--- a/lib/mutant/world.rb
+++ b/lib/mutant/world.rb
@@ -82,5 +82,9 @@ def deadline(allowed_time)
     def record(name, &block)
       recorder.record(name, &block)
     end
+
+    def process_warmup
+      process.warmup if process.respond_to?(:warmup)
+    end
   end # World
 end # Mutant
diff --git a/spec/unit/mutant/mutation/runner_spec.rb b/spec/unit/mutant/mutation/runner_spec.rb
index 9b1a0c480..b15da1aed 100644
--- a/spec/unit/mutant/mutation/runner_spec.rb
+++ b/spec/unit/mutant/mutation/runner_spec.rb
@@ -8,7 +8,8 @@
     let(:emit_mutation_worker_process_start) { instance_double(Proc)                           }
     let(:env_result)                         { instance_double(Mutant::Result::Env)            }
     let(:reporter)                           { instance_double(Mutant::Reporter, delay: delay) }
-    let(:world)                              { fake_world                                      }
+    let(:world)                              { instance_double(Mutant::World)                  }
+    let(:timer)                              { instance_double(Mutant::Timer)                  }
 
     let(:env) do
       instance_double(
@@ -55,6 +56,7 @@
     end
 
     before do
+      allow(world).to receive_messages(timer: timer)
       allow(world.timer).to receive_messages(now: 1.0)
     end
 
@@ -70,6 +72,11 @@ def apply
             selector:  :start,
             arguments: [env]
           },
+          {
+            receiver:  world,
+            selector:  :process_warmup,
+            arguments: []
+          },
           {
             receiver:  env,
             selector:  :record,
@@ -147,6 +154,11 @@ def apply
             selector:  :start,
             arguments: [env]
           },
+          {
+            receiver:  world,
+            selector:  :process_warmup,
+            arguments: [],
+          },
           {
             receiver:  env,
             selector:  :record,
diff --git a/spec/unit/mutant/world_spec.rb b/spec/unit/mutant/world_spec.rb
index a3c308c8b..65eaaec1a 100644
--- a/spec/unit/mutant/world_spec.rb
+++ b/spec/unit/mutant/world_spec.rb
@@ -140,4 +140,43 @@ def apply
       end
     end
   end
+
+  describe '#process_warmup' do
+    let(:process) { double(Process) }
+
+    subject { super().with(process: process) }
+
+    def apply
+      subject.process_warmup
+    end
+
+    before do
+      allow(process).to receive_messages(
+        respond_to?: respond_to?,
+        warmup:      process
+      )
+    end
+
+    context 'when process supports warmup' do
+      let(:respond_to?) { true }
+
+      it 'performs warmup' do
+        apply
+
+        expect(process).to have_received(:respond_to?).with(:warmup).ordered
+        expect(process).to have_received(:warmup).ordered
+      end
+    end
+
+    context 'when process supports warmup' do
+      let(:respond_to?) { false }
+
+      it 'performs warmup' do
+        apply
+
+        expect(process).to have_received(:respond_to?).with(:warmup)
+        expect(process).to_not have_received(:warmup)
+      end
+    end
+  end
 end