Berry format support width for %c format (#25122)

lib/libesp32/berry/berry_port/be_strlib.py

@@ -1373,7 +1373,10 @@ def be_str_format(vm):
             elif spec == 'c':
                 ok, val = _convert_to_int(vm, index)
                 if ok:
-                    buf = chr(int(val) & 0xFF)
+                    try:
+                        buf = mode % chr(int(val) & 0xFF)
+                    except (TypeError, ValueError):
+                        buf = chr(int(val) & 0xFF)
                 be_api.be_pushstring(vm, buf)
             elif spec == 's':
                 s = be_api.be_tostring(vm, index)

lib/libesp32/berry/src/be_strlib.c

@@ -832,7 +832,7 @@ int be_str_format(bvm *vm)
             {
                 bint val;
                 if (convert_to_int(vm, index, &val)) {
-                    snprintf(buf, sizeof(buf), "%c", (int)val);
+                    snprintf(buf, sizeof(buf), mode, (int)val);
                 }
                 be_pushstring(vm, buf);
                 break;

lib/libesp32/berry/tests/string.be

@@ -132,6 +132,9 @@ assert(string.format("%i", true) == '1')
 assert(string.format("%i", false) == '0')
 
 assert(string.format("%c", a) == '*')
+# %c must honor field width and flags, like the other conversions
+assert(string.format("%5c", 65) == '    A')
+assert(string.format("%-5c", 65) == 'A    ')
 
 assert(string.format("%f", 3.5) == '3.500000')
 assert(string.format("%f", 3) == '3.000000')