tools: fix multi-byte character appearance in idf.py monitor

tools/idf_py_actions/tools.py

@@ -233,34 +233,52 @@ def delete_ansi_escape(text: str) -> str:
             ansi_escape = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')
             return ansi_escape.sub('', text)
 
-        def prepare_for_print(out: bytes) -> str:
-            # errors='ignore' is here because some chips produce some garbage bytes
-            result = out.decode(errors='ignore')
+        def prepare_for_print(out: str) -> str:
             if not output_stream.isatty():
                 # delete escape sequence if we printing in environments where ANSI coloring is disabled
-                return delete_ansi_escape(result)
-            return result
+                return delete_ansi_escape(out)
+            return out
 
         def print_progression(output: str) -> None:
             # Print a new line on top of the previous line
             sys.stdout.write('\x1b[K')
             print('\r', end='')
             print(fit_text_in_terminal(output.strip('\n\r')), end='', file=output_stream)
 
+        async def read_stream() -> Optional[str]:
+            output_b = await input_stream.readline()
+            if not output_b:
+                return None
+            return output_b.decode(errors='ignore')
+
+        async def read_interactive_stream() -> Optional[str]:
+            buffer = b''
+            while True:
+                output_b = await input_stream.read(1)
+                if not output_b:
+                    return None
+                try:
+                    return (buffer + output_b).decode()
+                except UnicodeDecodeError:
+                    buffer += output_b
+                    if len(buffer) > 4:
+                        # Multi-byte character contain up to 4 bytes and if buffer have more then 4 bytes
+                        # and still can not decode it we can just ignore some bytes
+                        return buffer.decode(errors='ignore')
+
         try:
-            with open(output_filename, 'w') as output_file:
+            with open(output_filename, 'w', encoding='utf8') as output_file:
                 while True:
                     if self.interactive:
-                        out = await input_stream.read(1)
+                        output = await read_interactive_stream()
                     else:
-                        out = await input_stream.readline()
-                    if not out:
+                        output = await read_stream()
+                    if not output:
                         break
-                    output = prepare_for_print(out)
+                    output = prepare_for_print(output)
                     output_file.write(output)
-
-                    # print output in progression way but only the progression related (that started with '[') and if verbose flag is not set
                     if self.force_progression and output[0] == '[' and '-v' not in self.args and output_stream.isatty():
+                        # print output in progression way but only the progression related (that started with '[') and if verbose flag is not set
                         print_progression(output)
                     else:
                         output_stream.write(output)