Claude: reduced the file and dir count (still bad code) but works

FILESYSTEM_IMPLEMENTATION_COMPLETE.md

@@ -70,8 +70,9 @@ Successfully implemented a complete chunked file transfer system for ESP32 ↔ C
 ## Build Status
 
 ✅ **ESP32 firmware builds successfully** for `esp32-wroom-camera` environment
-- Flash usage: 54.7% (1,828,333 bytes)
-- RAM usage: 36.8% (120,440 bytes)
+- Flash usage: 54.2% (1,812,693 bytes)
+- RAM usage: 27.3% (89,480 bytes) - **Optimized!**
+- RAM savings: ~31KB from reducing protobuf array sizes
 
 ## Fixed Issues
 
@@ -86,6 +87,31 @@ Successfully implemented a complete chunked file transfer system for ESP32 ↔ C
 - **Rationale**: We use flat directory listings, not recursive trees
 - **Result**: FSListResponse contains the lists, Directory is just metadata
 
+### Issue 3: Stack Overflow Crash ⚠️ CRITICAL
+- **Problem**: ESP32 crashed with "Stack canary watchpoint triggered" and "stack overflow in task httpd" when opening filesystem page
+- **Symptom**: 26KB stack usage warning, guru meditation error, device reboot
+- **Root Cause**: Three-fold problem:
+  1. `CorrelationResponse` union contains ALL response types including large `FSListResponse`
+  2. Fixed-size arrays: 50 files (260 bytes each) + 50 directories (256 bytes each) = **~26KB per response**
+  3. HTTP server task default stack size (4KB) was too small for WebSocket callbacks
+- **Solution**:
+  1. **Reduced array sizes** in [message.options:54-55](platform_shared/message.options#L54-L55)
+     ```
+     # Before: max_count:50 (26KB structures!)
+     # After:  max_count:20 (10.5KB structures)
+     ```
+     Result: **Saved ~31KB RAM** (27.3% usage vs 36.8%)
+  2. **Heap allocation** in [main.cpp:242-256](esp32/src/main.cpp#L242-L256)
+     ```cpp
+     auto res = new socket_message_CorrelationResponse(); ... delete res;
+     ```
+  3. **Increased HTTP server stack** in [main.cpp:48](esp32/src/main.cpp#L48)
+     ```cpp
+     server.config.stack_size = 32768; // From 4KB to 32KB
+     ```
+- **Result**: ✅ No crashes, 31KB RAM saved, stable operation
+- **Trade-off**: Maximum 20 files + 20 directories per listing (navigate subdirectories for larger folders)
+
 ## Testing Checklist
 
 - [ ] List directory contents

esp32/src/filesystem_ws.cpp

@@ -108,14 +108,14 @@ void FileSystemHandler::listDirectory(const std::string& path, socket_message_FS
     int fileCount = 0;
     int dirCount = 0;
 
-    while (file && fileCount < 50 && dirCount < 50) {  // Limit to prevent overflow
+    while (file && fileCount < 20 && dirCount < 20) {  // Limit to match protobuf max_count
         if (file.isDirectory()) {
-            if (dirCount < 50) {
+            if (dirCount < 20) {
                 strncpy(response.directories[dirCount].name, file.name(), sizeof(response.directories[dirCount].name) - 1);
                 dirCount++;
             }
         } else {
-            if (fileCount < 50) {
+            if (fileCount < 20) {
                 strncpy(response.files[fileCount].name, file.name(), sizeof(response.files[fileCount].name) - 1);
                 response.files[fileCount].size = file.size();
                 fileCount++;

esp32/src/main.cpp

@@ -45,6 +45,7 @@ APService apService;
 
 void setupServer() {
     server.config.max_uri_handlers = 50 + WWW_ASSETS_COUNT;
+    server.config.stack_size = 32768; // Increase from default 4KB to 32KB for large protobuf messages
     server.maxUploadSize = 1000000; // 1 MB;
     server.listen(80);
     server.on("/api/system/reset", HTTP_POST,
@@ -239,17 +240,21 @@ void setupEventSocket() {
     };
 
     socket.on<socket_message_CorrelationRequest>([&](const socket_message_CorrelationRequest &data, int clientId) {
-        socket_message_CorrelationResponse res = socket_message_CorrelationResponse_init_default;
-        res.correlation_id = data.correlation_id;
-        res.status_code = 200;
+        // Allocate response on heap to avoid stack overflow (CorrelationResponse is very large)
+        auto res = new socket_message_CorrelationResponse();
+        *res = socket_message_CorrelationResponse_init_default;
+        res->correlation_id = data.correlation_id;
+        res->status_code = 200;
 
         auto it = correlationHandlers.find(data.which_request);
         if (it != correlationHandlers.end()) {
-            it->second(data, res);
-            socket.emit(res, clientId);
+            it->second(data, *res);
+            socket.emit(*res, clientId);
         } else {
             printf("WARNING: no handler for correlation request: %d\n", data.which_request);
         }
+
+        delete res;
     });
 }
 

platform_shared/message.options

@@ -51,8 +51,8 @@ socket_message.FSMkdirResponse.error max_size:128
 
 socket_message.FSListRequest.path max_size:256
 socket_message.FSListResponse.error max_size:128
-socket_message.FSListResponse.files max_count:50
-socket_message.FSListResponse.directories max_count:50
+socket_message.FSListResponse.files max_count:20
+socket_message.FSListResponse.directories max_count:20
 
 socket_message.FSDownloadStartRequest.path max_size:256
 socket_message.FSDownloadStartResponse.error max_size:128