[BUG] Display glitch: sometimes, menu briefly shows "????" when returning via touchscreen

[mcarbonne]

Printer model

Core One L

Firmware version

6.3.5

Upgrades and modifications

None

Printing from...

N.A.

Describe the bug

When returning from a sub-menu (such as Settings or Control) using the touchscreen, a transient rendering glitch occurs where the returning menu item (such as the "Return" line) is briefly filled with ???? characters. This usually means that a buffer overflow is occurring somewhere.

How to reproduce

When it occurred, I was able to reproduce the bug several times. But I still did not manage to reproduce it since.
I asked AI to investigate and it suggested the following patches :

diff --git a/src/guiapi/src/i_window_menu_item.cpp b/src/guiapi/src/i_window_menu_item.cpp
index bdadab108..6907775a6 100644
--- a/src/guiapi/src/i_window_menu_item.cpp
+++ b/src/guiapi/src/i_window_menu_item.cpp
@@ -49,6 +49,7 @@ IWindowMenuItem::~IWindowMenuItem() {
     if (focused_menu_item == this) {
         focused_menu_item = nullptr;
         focused_menu_item_edited = false;
+        focused_menu_item_roll.Deinit();
     }
 }
 
diff --git a/src/guiapi/src/text_roll.cpp b/src/guiapi/src/text_roll.cpp
index 0f67e4e3e..323ad9d36 100644
--- a/src/guiapi/src/text_roll.cpp
+++ b/src/guiapi/src/text_roll.cpp
@@ -77,6 +77,10 @@ invalidate_t txtroll_t::Tick() {
 void txtroll_t::Init(const Rect16 &rect, const string_view_utf8 &text, Font font, padding_ui8_t padding) {
     hidden_char_cnt = meas(rect, text, font, padding);
     font_w = resource_font(font)->w;
+    draw_progress = 0;
+    px_cd = 0;
+    count = 0;
+    phase_progress = 0;
     phase = phase_t::init_roll;
 }
 

and another (unrelated ?) fix:

diff --git a/src/lang/string_view_utf8.cpp b/src/lang/string_view_utf8.cpp
index a482888f1..3c3a415bb 100644
--- a/src/lang/string_view_utf8.cpp
+++ b/src/lang/string_view_utf8.cpp
@@ -193,7 +193,9 @@ bool StringReaderUtf8::trigger_buffer_switch(uint8_t ch) {
 
 StringReaderUtf8 &StringReaderUtf8::skip(uint16_t num_of_chars) {
     while (num_of_chars--) {
-        getUtf8Char();
+        if (getUtf8Char() == '\0') {
+            break;
+        }
     }
     return *this;
 }
@@ -238,7 +240,9 @@ void StringReaderUtf8::advance() {
 
     switch (view_.type()) {
     case Type::memory_string:
-        view_.memory_ptr++;
+        if (*view_.memory_ptr != '\0') {
+            view_.memory_ptr++;
+        }
         break;
 
     case Type::file_string:
diff --git a/tests/unit/lang/string_view_utf8/tests.cpp b/tests/unit/lang/string_view_utf8/tests.cpp
index 9dda0ca98..fb61d4057 100644
--- a/tests/unit/lang/string_view_utf8/tests.cpp
+++ b/tests/unit/lang/string_view_utf8/tests.cpp
@@ -292,3 +292,16 @@ TEST_CASE("string_view_utf8::string_build", "[string_view_utf8]") {
     REQUIRE_THAT(compare_buff, Equals(ref_text_in_between));
     REQUIRE(copied_bytes == strlen(ref_text_in_between));
 }
+
+TEST_CASE("string_view_utf8::StringReaderUtf8 safety checks", "[string_view_utf8]") {
+    static const uint8_t utf8str[] = "Return";
+    string_view_utf8 sf = string_view_utf8::MakeRAM(utf8str);
+    StringReaderUtf8 reader(sf);
+
+    // Skip way past the end of the string
+    reader.skip(100);
+
+    // Ensure we are stuck at null terminator and it doesn't read garbage
+    REQUIRE(reader.getUtf8Char() == '\0');
+    REQUIRE(reader.getbyte() == '\0');
+}

Also, just before having the bug, I did several calibrations (belt tension, phase stepping, input shaper).

Expected behavior

No response

Files

No response