Fix scheduler race conditions and add comprehensive test suite (#9348)

tests/integration/fixtures/external_components/scheduler_rapid_cancellation_component/__init__.py

@@ -0,0 +1,21 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.const import CONF_ID
+
+scheduler_rapid_cancellation_component_ns = cg.esphome_ns.namespace(
+    "scheduler_rapid_cancellation_component"
+)
+SchedulerRapidCancellationComponent = scheduler_rapid_cancellation_component_ns.class_(
+    "SchedulerRapidCancellationComponent", cg.Component
+)
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(): cv.declare_id(SchedulerRapidCancellationComponent),
+    }
+).extend(cv.COMPONENT_SCHEMA)
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)

tests/integration/fixtures/external_components/scheduler_rapid_cancellation_component/rapid_cancellation_component.cpp

@@ -0,0 +1,80 @@
+#include "rapid_cancellation_component.h"
+#include "esphome/core/log.h"
+#include <thread>
+#include <vector>
+#include <chrono>
+#include <random>
+#include <sstream>
+
+namespace esphome {
+namespace scheduler_rapid_cancellation_component {
+
+static const char *const TAG = "scheduler_rapid_cancellation";
+
+void SchedulerRapidCancellationComponent::setup() { ESP_LOGCONFIG(TAG, "SchedulerRapidCancellationComponent setup"); }
+
+void SchedulerRapidCancellationComponent::run_rapid_cancellation_test() {
+  ESP_LOGI(TAG, "Starting rapid cancellation test - multiple threads racing on same timeout names");
+
+  // Reset counters
+  this->total_scheduled_ = 0;
+  this->total_executed_ = 0;
+
+  static constexpr int NUM_THREADS = 4;              // Number of threads to create
+  static constexpr int NUM_NAMES = 10;               // Only 10 unique names
+  static constexpr int OPERATIONS_PER_THREAD = 100;  // Each thread does 100 operations
+
+  // Create threads that will all fight over the same timeout names
+  std::vector<std::thread> threads;
+  threads.reserve(NUM_THREADS);
+
+  for (int thread_id = 0; thread_id < NUM_THREADS; thread_id++) {
+    threads.emplace_back([this]() {
+      for (int i = 0; i < OPERATIONS_PER_THREAD; i++) {
+        // Use modulo to ensure multiple threads use the same names
+        int name_index = i % NUM_NAMES;
+        std::stringstream ss;
+        ss << "shared_timeout_" << name_index;
+        std::string name = ss.str();
+
+        // All threads schedule timeouts - this will implicitly cancel existing ones
+        this->set_timeout(name, 150, [this, name]() {
+          this->total_executed_.fetch_add(1);
+          ESP_LOGI(TAG, "Executed callback '%s'", name.c_str());
+        });
+        this->total_scheduled_.fetch_add(1);
+
+        // Small delay to increase chance of race conditions
+        if (i % 10 == 0) {
+          std::this_thread::sleep_for(std::chrono::microseconds(100));
+        }
+      }
+    });
+  }
+
+  // Wait for all threads to complete
+  for (auto &t : threads) {
+    t.join();
+  }
+
+  ESP_LOGI(TAG, "All threads completed. Scheduled: %d", this->total_scheduled_.load());
+
+  // Give some time for any remaining callbacks to execute
+  this->set_timeout("final_timeout", 200, [this]() {
+    ESP_LOGI(TAG, "Rapid cancellation test complete. Final stats:");
+    ESP_LOGI(TAG, "  Total scheduled: %d", this->total_scheduled_.load());
+    ESP_LOGI(TAG, "  Total executed: %d", this->total_executed_.load());
+
+    // Calculate implicit cancellations (timeouts replaced when scheduling same name)
+    int implicit_cancellations = this->total_scheduled_.load() - this->total_executed_.load();
+    ESP_LOGI(TAG, "  Implicit cancellations (replaced): %d", implicit_cancellations);
+    ESP_LOGI(TAG, "  Total accounted: %d (executed + implicit cancellations)",
+             this->total_executed_.load() + implicit_cancellations);
+
+    // Final message to signal test completion - ensures all stats are logged before test ends
+    ESP_LOGI(TAG, "Test finished - all statistics reported");
+  });
+}
+
+}  // namespace scheduler_rapid_cancellation_component
+}  // namespace esphome

tests/integration/fixtures/external_components/scheduler_rapid_cancellation_component/rapid_cancellation_component.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include <atomic>
+
+namespace esphome {
+namespace scheduler_rapid_cancellation_component {
+
+class SchedulerRapidCancellationComponent : public Component {
+ public:
+  void setup() override;
+  float get_setup_priority() const override { return setup_priority::LATE; }
+
+  void run_rapid_cancellation_test();
+
+ private:
+  std::atomic<int> total_scheduled_{0};
+  std::atomic<int> total_executed_{0};
+};
+
+}  // namespace scheduler_rapid_cancellation_component
+}  // namespace esphome