From 5133a49f83c140ce93787e691dbe776b627d1ab5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 27 Mar 2026 13:32:10 -1000
Subject: [PATCH] [sensor] Use std::array in OrFilter

---
 esphome/components/sensor/__init__.py |  2 +-
 esphome/components/sensor/filter.cpp  | 30 ++++++--------------
 esphome/components/sensor/filter.h    | 40 +++++++++++++++++++++------
 3 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/esphome/components/sensor/__init__.py b/esphome/components/sensor/__init__.py
index 9f3c1484b0..e4bdc1186f 100644
--- a/esphome/components/sensor/__init__.py
+++ b/esphome/components/sensor/__init__.py
@@ -636,7 +636,7 @@ async def delta_filter_to_code(config, filter_id):
 @FILTER_REGISTRY.register("or", OrFilter, validate_filters)
 async def or_filter_to_code(config, filter_id):
     filters = await build_filters(config)
-    return cg.new_Pvariable(filter_id, filters)
+    return cg.new_Pvariable(filter_id, cg.TemplateArguments(len(filters)), filters)
 
 
 @FILTER_REGISTRY.register(
diff --git a/esphome/components/sensor/filter.cpp b/esphome/components/sensor/filter.cpp
index d995ee4111..51dc47ea87 100644
--- a/esphome/components/sensor/filter.cpp
+++ b/esphome/components/sensor/filter.cpp
@@ -311,32 +311,20 @@ optional<float> DeltaFilter::new_value(float value) {
   return {};
 }
 
-// OrFilter
-OrFilter::OrFilter(std::initializer_list<Filter *> filters) : filters_(filters), phi_(this) {}
-OrFilter::PhiNode::PhiNode(OrFilter *or_parent) : or_parent_(or_parent) {}
-
-optional<float> OrFilter::PhiNode::new_value(float value) {
-  if (!this->or_parent_->has_value_) {
-    this->or_parent_->output(value);
-    this->or_parent_->has_value_ = true;
+// OrFilter helpers
+void or_filter_initialize(Filter **filters, size_t count, Sensor *parent, Filter *phi) {
+  for (size_t i = 0; i < count; i++) {
+    filters[i]->initialize(parent, phi);
   }
-
-  return {};
+  phi->initialize(parent, nullptr);
 }
-optional<float> OrFilter::new_value(float value) {
-  this->has_value_ = false;
-  for (auto *filter : this->filters_)
-    filter->input(value);
 
+optional<float> or_filter_new_value(Filter **filters, size_t count, float value, bool &has_value) {
+  has_value = false;
+  for (size_t i = 0; i < count; i++)
+    filters[i]->input(value);
   return {};
 }
-void OrFilter::initialize(Sensor *parent, Filter *next) {
-  Filter::initialize(parent, next);
-  for (auto *filter : this->filters_) {
-    filter->initialize(parent, &this->phi_);
-  }
-  this->phi_.initialize(parent, nullptr);
-}
 
 // TimeoutFilterBase - shared loop logic
 void TimeoutFilterBase::loop() {
diff --git a/esphome/components/sensor/filter.h b/esphome/components/sensor/filter.h
index 6a76bd373e..21dfdd3ddc 100644
--- a/esphome/components/sensor/filter.h
+++ b/esphome/components/sensor/filter.h
@@ -3,6 +3,7 @@
 #include "esphome/core/defines.h"
 #ifdef USE_SENSOR_FILTER
 
+#include <array>
 #include <utility>
 #include <vector>
 #include "esphome/core/automation.h"
@@ -466,26 +467,49 @@ class DeltaFilter : public Filter {
   float last_value_{NAN};
 };
 
-class OrFilter : public Filter {
+/// Non-template helpers for OrFilter (implementation in filter.cpp)
+void or_filter_initialize(Filter **filters, size_t count, Sensor *parent, Filter *phi);
+optional<float> or_filter_new_value(Filter **filters, size_t count, float value, bool &has_value);
+
+/// N is set by code generation to match the exact number of filters configured in YAML.
+template<size_t N> class OrFilter : public Filter {
  public:
-  explicit OrFilter(std::initializer_list<Filter *> filters);
+  explicit OrFilter(std::initializer_list<Filter *> filters) {
+    size_t i = 0;
+    for (auto *f : filters) {
+      if (i >= N)
+        break;
+      this->filters_[i++] = f;
+    }
+  }
 
-  void initialize(Sensor *parent, Filter *next) override;
+  void initialize(Sensor *parent, Filter *next) override {
+    Filter::initialize(parent, next);
+    or_filter_initialize(this->filters_.data(), N, parent, &this->phi_);
+  }
 
-  optional<float> new_value(float value) override;
+  optional<float> new_value(float value) override {
+    return or_filter_new_value(this->filters_.data(), N, value, this->has_value_);
+  }
 
  protected:
   class PhiNode : public Filter {
    public:
-    PhiNode(OrFilter *or_parent);
-    optional<float> new_value(float value) override;
+    PhiNode(OrFilter *or_parent) : or_parent_(or_parent) {}
+    optional<float> new_value(float value) override {
+      if (!this->or_parent_->has_value_) {
+        this->or_parent_->output(value);
+        this->or_parent_->has_value_ = true;
+      }
+      return {};
+    }
 
    protected:
     OrFilter *or_parent_;
   };
 
-  FixedVector<Filter *> filters_;
-  PhiNode phi_;
+  std::array<Filter *, N> filters_{};
+  PhiNode phi_{this};
   bool has_value_{false};
 };