Merge branch 'fix/prompt-erased-by-backspace-in-dumbmode' into 'master'

fix(console): bug where backspace erases the prompt in dumb mode

Closes IDFGH-12508

See merge request espressif/esp-idf!30313

Author: SoucheSouche

components/console/linenoise/linenoise.c

@@ -178,6 +178,7 @@ enum KEY_ACTION{
 	CTRL_U = 21,        /* Ctrl+u */
 	CTRL_W = 23,        /* Ctrl+w */
 	ESC = 27,           /* Escape */
+	UNIT_SEP = 31,      /* ctrl-_ */
 	BACKSPACE =  127    /* Backspace */
 };
 
@@ -1131,15 +1132,23 @@ static int linenoiseDumb(char* buf, size_t buflen, const char* prompt) {
         int c = fgetc(stdin);
         if (c == '\n') {
             break;
-        } else if (c >= 0x1c && c <= 0x1f){
-            continue; /* consume arrow keys */
-        } else if (c == BACKSPACE || c == 0x8) {
+        } else if (c == BACKSPACE || c == CTRL_H) {
             if (count > 0) {
                 buf[count - 1] = 0;
-                count --;
+                count--;
+
+                /* Only erase symbol echoed from stdin. */
+                fputs("\x08 ", stdout); /* Windows CMD: erase symbol under cursor */
+                flushWrite();
+            } else {
+                /* Consume backspace if the command line is empty to avoid erasing the prompt */
+                continue;
             }
-            fputs("\x08 ", stdout); /* Windows CMD: erase symbol under cursor */
-            flushWrite();
+
+        } else if (c <= UNIT_SEP) {
+            /* Consume all character that are non printable (the backspace
+             * case is handled above) */
+            continue;
         } else {
             buf[count] = c;
             ++count;