From 3e4269d32ab7e1878c3c85ca4c1955a23e533266 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 6 Feb 2026 21:35:23 +0100
Subject: [PATCH] Address review: add SSD1306_MODEL_COUNT sentinel and bounds
 checks

- Add SSD1306_MODEL_COUNT sentinel to enum for compile-time table size validation
- Replace 14 individual static_asserts with table size checks against SSD1306_MODEL_COUNT
- Add bounds checks in get_height_internal()/get_width_internal() to preserve default return 0
---
 .../components/ssd1306_base/ssd1306_base.cpp  | 33 +++++++++----------
 .../components/ssd1306_base/ssd1306_base.h    |  6 ++--
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/esphome/components/ssd1306_base/ssd1306_base.cpp b/esphome/components/ssd1306_base/ssd1306_base.cpp
index af498aae6c..1220f74fbc 100644
--- a/esphome/components/ssd1306_base/ssd1306_base.cpp
+++ b/esphome/components/ssd1306_base/ssd1306_base.cpp
@@ -41,21 +41,8 @@ static const uint8_t SSD1305_COMMAND_SET_AREA_COLOR = 0xD8;
 static const uint8_t SH1107_COMMAND_SET_START_LINE = 0xDC;
 static const uint8_t SH1107_COMMAND_CHARGE_PUMP = 0xAD;
 
-// Verify SSD1306Model enum is sequential 0-13 so we can use it as a table index
-static_assert(SSD1306_MODEL_128_32 == 0, "SSD1306Model enum values must match table indices");
-static_assert(SSD1306_MODEL_128_64 == 1, "SSD1306Model enum values must match table indices");
-static_assert(SSD1306_MODEL_96_16 == 2, "SSD1306Model enum values must match table indices");
-static_assert(SSD1306_MODEL_64_48 == 3, "SSD1306Model enum values must match table indices");
-static_assert(SSD1306_MODEL_64_32 == 4, "SSD1306Model enum values must match table indices");
-static_assert(SSD1306_MODEL_72_40 == 5, "SSD1306Model enum values must match table indices");
-static_assert(SH1106_MODEL_128_32 == 6, "SSD1306Model enum values must match table indices");
-static_assert(SH1106_MODEL_128_64 == 7, "SSD1306Model enum values must match table indices");
-static_assert(SH1106_MODEL_96_16 == 8, "SSD1306Model enum values must match table indices");
-static_assert(SH1106_MODEL_64_48 == 9, "SSD1306Model enum values must match table indices");
-static_assert(SH1107_MODEL_128_64 == 10, "SSD1306Model enum values must match table indices");
-static_assert(SH1107_MODEL_128_128 == 11, "SSD1306Model enum values must match table indices");
-static_assert(SSD1305_MODEL_128_32 == 12, "SSD1306Model enum values must match table indices");
-static_assert(SSD1305_MODEL_128_64 == 13, "SSD1306Model enum values must match table indices");
+// Verify first enum value and table sizes match SSD1306_MODEL_COUNT
+static_assert(SSD1306_MODEL_128_32 == 0, "SSD1306Model enum must start at 0");
 
 // PROGMEM lookup table indexed by SSD1306Model enum (width, height per model)
 struct ModelDimensions {
@@ -98,6 +85,10 @@ PROGMEM_STRING_TABLE(ModelStrings,
     "Unknown"          // fallback
 );
 // clang-format on
+static_assert(sizeof(MODEL_DIMS) / sizeof(MODEL_DIMS[0]) == SSD1306_MODEL_COUNT,
+              "MODEL_DIMS must have one entry per SSD1306Model");
+static_assert(ModelStrings::COUNT == SSD1306_MODEL_COUNT + 1,
+              "ModelStrings must have one entry per SSD1306Model plus fallback");
 
 void SSD1306::setup() {
   this->init_internal_(this->get_buffer_length_());
@@ -332,8 +323,16 @@ void SSD1306::turn_off() {
   this->command(SSD1306_COMMAND_DISPLAY_OFF);
   this->is_on_ = false;
 }
-int SSD1306::get_height_internal() { return progmem_read_byte(&MODEL_DIMS[this->model_].height); }
-int SSD1306::get_width_internal() { return progmem_read_byte(&MODEL_DIMS[this->model_].width); }
+int SSD1306::get_height_internal() {
+  if (this->model_ >= SSD1306_MODEL_COUNT)
+    return 0;
+  return progmem_read_byte(&MODEL_DIMS[this->model_].height);
+}
+int SSD1306::get_width_internal() {
+  if (this->model_ >= SSD1306_MODEL_COUNT)
+    return 0;
+  return progmem_read_byte(&MODEL_DIMS[this->model_].width);
+}
 size_t SSD1306::get_buffer_length_() {
   return size_t(this->get_width_internal()) * size_t(this->get_height_internal()) / 8u;
 }
diff --git a/esphome/components/ssd1306_base/ssd1306_base.h b/esphome/components/ssd1306_base/ssd1306_base.h
index 61cd7fc4cc..3cc795a323 100644
--- a/esphome/components/ssd1306_base/ssd1306_base.h
+++ b/esphome/components/ssd1306_base/ssd1306_base.h
@@ -5,9 +5,6 @@
 #include "esphome/components/display/display_buffer.h"
 
 namespace esphome {
-
-struct LogString;
-
 namespace ssd1306_base {
 
 enum SSD1306Model {
@@ -25,6 +22,9 @@ enum SSD1306Model {
   SH1107_MODEL_128_128,
   SSD1305_MODEL_128_32,
   SSD1305_MODEL_128_64,
+  // When adding a new model, add it before SSD1306_MODEL_COUNT and update
+  // MODEL_DIMS and ModelStrings tables in ssd1306_base.cpp
+  SSD1306_MODEL_COUNT,  // must be last
 };
 
 class SSD1306 : public display::DisplayBuffer {