[sensor] Use std::array in ValueList/FilterOut/ThrottleWithPriority filters (#15265)

esphome/components/sensor/__init__.py

@@ -381,7 +381,7 @@ async def filter_out_filter_to_code(config, filter_id):
     if not isinstance(config, list):
         config = [config]
     template_ = [await cg.templatable(x, [], float) for x in config]
-    return cg.new_Pvariable(filter_id, template_)
+    return cg.new_Pvariable(filter_id, cg.TemplateArguments(len(template_)), template_)
 
 
 QUANTILE_SCHEMA = cv.All(
@@ -650,7 +650,9 @@ async def throttle_with_priority_filter_to_code(config, filter_id):
     if not isinstance(config[CONF_VALUE], list):
         config[CONF_VALUE] = [config[CONF_VALUE]]
     template_ = [await cg.templatable(x, [], float) for x in config[CONF_VALUE]]
-    return cg.new_Pvariable(filter_id, config[CONF_TIMEOUT], template_)
+    return cg.new_Pvariable(
+        filter_id, cg.TemplateArguments(len(template_)), config[CONF_TIMEOUT], template_
+    )
 
 
 HEARTBEAT_SCHEMA = cv.Schema(

esphome/components/sensor/filter.cpp

@@ -222,16 +222,14 @@ MultiplyFilter::MultiplyFilter(TemplatableValue<float> multiplier) : multiplier_
 
 optional<float> MultiplyFilter::new_value(float value) { return value * this->multiplier_.value(); }
 
-// ValueListFilter (base class)
-ValueListFilter::ValueListFilter(std::initializer_list<TemplatableValue<float>> values) : values_(values) {}
-
-bool ValueListFilter::value_matches_any_(float sensor_value) {
-  int8_t accuracy = this->parent_->get_accuracy_decimals();
+// ValueListFilter helper (non-template, shared by all ValueListFilter<N> instantiations)
+bool value_list_matches_any(Sensor *parent, float sensor_value, const TemplatableValue<float> *values, size_t count) {
+  int8_t accuracy = parent->get_accuracy_decimals();
   float accuracy_mult = pow10_int(accuracy);
   float rounded_sensor = roundf(accuracy_mult * sensor_value);
 
-  for (auto &filter_value : this->values_) {
-    float fv = filter_value.value();
+  for (size_t i = 0; i < count; i++) {
+    float fv = values[i].value();
 
     // Handle NaN comparison
     if (std::isnan(fv)) {
@@ -248,16 +246,6 @@ bool ValueListFilter::value_matches_any_(float sensor_value) {
   return false;
 }
 
-// FilterOutValueFilter
-FilterOutValueFilter::FilterOutValueFilter(std::initializer_list<TemplatableValue<float>> values_to_filter_out)
-    : ValueListFilter(values_to_filter_out) {}
-
-optional<float> FilterOutValueFilter::new_value(float value) {
-  if (this->value_matches_any_(value))
-    return {};   // Filter out
-  return value;  // Pass through
-}
-
 // ThrottleFilter
 ThrottleFilter::ThrottleFilter(uint32_t min_time_between_inputs) : min_time_between_inputs_(min_time_between_inputs) {}
 optional<float> ThrottleFilter::new_value(float value) {
@@ -269,17 +257,13 @@ optional<float> ThrottleFilter::new_value(float value) {
   return {};
 }
 
-// ThrottleWithPriorityFilter
-ThrottleWithPriorityFilter::ThrottleWithPriorityFilter(
-    uint32_t min_time_between_inputs, std::initializer_list<TemplatableValue<float>> prioritized_values)
-    : ValueListFilter(prioritized_values), min_time_between_inputs_(min_time_between_inputs) {}
-
-optional<float> ThrottleWithPriorityFilter::new_value(float value) {
+// ThrottleWithPriorityFilter helper (non-template, keeps App access in .cpp)
+optional<float> throttle_with_priority_new_value(Sensor *parent, float value, const TemplatableValue<float> *values,
+                                                 size_t count, uint32_t &last_input, uint32_t min_time_between_inputs) {
   const uint32_t now = App.get_loop_component_start_time();
-  // Allow value through if: no previous input, time expired, or is prioritized
-  if (this->last_input_ == 0 || now - this->last_input_ >= min_time_between_inputs_ ||
-      this->value_matches_any_(value)) {
-    this->last_input_ = now;
+  if (last_input == 0 || now - last_input >= min_time_between_inputs ||
+      value_list_matches_any(parent, value, values, count)) {
+    last_input = now;
     return value;
   }
   return {};

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"
@@ -328,28 +329,42 @@ class MultiplyFilter : public Filter {
   TemplatableValue<float> multiplier_;
 };
 
-/** Base class for filters that compare sensor values against a list of configured values.
+/// Non-template helper for value matching (implementation in filter.cpp)
+bool value_list_matches_any(Sensor *parent, float sensor_value, const TemplatableValue<float> *values, size_t count);
+
+/** Base class for filters that compare sensor values against a fixed list of configured values.
  *
- * This base class provides common functionality for filters that need to check if a sensor
- * value matches any value in a configured list, with proper handling of NaN values and
- * accuracy-based rounding for comparisons.
+ * Templated on N (the number of values) so the list is stored inline in a std::array,
+ * avoiding heap allocation and the overhead of FixedVector.
+ *
+ * @tparam N Number of values in the filter list, set by code generation to match
+ *           the exact number of values configured in YAML.
  */
-class ValueListFilter : public Filter {
+template<size_t N> class ValueListFilter : public Filter {
  protected:
-  explicit ValueListFilter(std::initializer_list<TemplatableValue<float>> values);
+  explicit ValueListFilter(std::initializer_list<TemplatableValue<float>> values) {
+    init_array_from(this->values_, values);
+  }
 
   /// Check if sensor value matches any configured value (with accuracy rounding)
-  bool value_matches_any_(float sensor_value);
+  bool value_matches_any_(float sensor_value) {
+    return value_list_matches_any(this->parent_, sensor_value, this->values_.data(), N);
+  }
 
-  FixedVector<TemplatableValue<float>> values_;
+  std::array<TemplatableValue<float>, N> values_{};
 };
 
 /// A simple filter that only forwards the filter chain if it doesn't receive `value_to_filter_out`.
-class FilterOutValueFilter : public ValueListFilter {
+template<size_t N> class FilterOutValueFilter : public ValueListFilter<N> {
  public:
-  explicit FilterOutValueFilter(std::initializer_list<TemplatableValue<float>> values_to_filter_out);
+  explicit FilterOutValueFilter(std::initializer_list<TemplatableValue<float>> values_to_filter_out)
+      : ValueListFilter<N>(values_to_filter_out) {}
 
-  optional<float> new_value(float value) override;
+  optional<float> new_value(float value) override {
+    if (this->value_matches_any_(value))
+      return {};   // Filter out
+    return value;  // Pass through
+  }
 };
 
 class ThrottleFilter : public Filter {
@@ -363,13 +378,21 @@ class ThrottleFilter : public Filter {
   uint32_t min_time_between_inputs_;
 };
 
+/// Non-template helper for ThrottleWithPriorityFilter (implementation in filter.cpp)
+optional<float> throttle_with_priority_new_value(Sensor *parent, float value, const TemplatableValue<float> *values,
+                                                 size_t count, uint32_t &last_input, uint32_t min_time_between_inputs);
+
 /// Same as 'throttle' but will immediately publish values contained in `value_to_prioritize`.
-class ThrottleWithPriorityFilter : public ValueListFilter {
+template<size_t N> class ThrottleWithPriorityFilter : public ValueListFilter<N> {
  public:
   explicit ThrottleWithPriorityFilter(uint32_t min_time_between_inputs,
-                                      std::initializer_list<TemplatableValue<float>> prioritized_values);
+                                      std::initializer_list<TemplatableValue<float>> prioritized_values)
+      : ValueListFilter<N>(prioritized_values), min_time_between_inputs_(min_time_between_inputs) {}
 
-  optional<float> new_value(float value) override;
+  optional<float> new_value(float value) override {
+    return throttle_with_priority_new_value(this->parent_, value, this->values_.data(), N, this->last_input_,
+                                            this->min_time_between_inputs_);
+  }
 
  protected:
   uint32_t last_input_{0};

esphome/core/helpers.h

@@ -2,6 +2,7 @@
 
 #include <algorithm>
 #include <array>
+#include <cassert>
 #include <cmath>
 #include <cstdarg>
 #include <cstdint>
@@ -497,6 +498,23 @@ template<typename T, size_t MAX_CAPACITY = std::numeric_limits<uint16_t>::max()>
   index_type capacity_{0};
 };
 
+/// Initialize a std::array from an initializer_list. Uses memcpy for trivially copyable types (optimal codegen),
+/// falls back to element-wise copy for non-trivially copyable types (e.g. TemplatableValue).
+/// N is set by code generation; assert catches mismatches in debug/integration tests.
+template<typename T, size_t N> inline void init_array_from(std::array<T, N> &dest, std::initializer_list<T> src) {
+#ifdef ESPHOME_DEBUG
+  assert(src.size() == N);
+#endif
+  if constexpr (std::is_trivially_copyable_v<T>) {
+    __builtin_memcpy(dest.data(), src.begin(), N * sizeof(T));
+  } else {
+    size_t i = 0;
+    for (const auto &v : src) {
+      dest[i++] = v;
+    }
+  }
+}
+
 /// Fixed-capacity vector - allocates once at runtime, never reallocates
 /// This avoids std::vector template overhead (_M_realloc_insert, _M_default_append)
 /// when size is known at initialization but not at compile time