Chinese Character Truncation in REPL Output

[udreams]

Describe the bug
In the MicroPython REPL, when printing Chinese text that exceeds the terminal line width, some characters are truncated. This issue does not occur with English text.

To Reproduce
Execute the following code in main.py
print('你好，世界！' * 30)

Expected behavior
The full Chinese string should be printed without truncation:
你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！你好，世界！
But, in actual, some Chinese characters are missing when the text wraps to a new line.

Screenshots or a Video

Desktop (please provide the following information):

• OS: Windows
• IDE PyCharm Community
• IDE Version 2025.1.3

MicroPython Board information (please complete the following information):

• Board: ESP32
• Version: 1.25.0

MicroPython Tools plugin

• Version: 0.5.10
• Used connection type Serial

Additional context
The issue may be caused by Chinese characters being treated as single-width characters.

[lukaskremla]

I'll look into this - I'm not sure how much I'll be able to do something with it, since it very well could be a problem with the built-in JetBrains terminal widget this plugin uses.

[udreams]

Thank you for looking into this! I really appreciate your time and effort, even if it turns out to be a limitation of the JetBrains terminal widget. Thanks again!

[lukaskremla]

I can confirm that the problem stems from the JBTerminalWidget element that the plugin uses.

CJK characters seem to not be supported by this widget, at least not by default or in a way that would be easy to enable.

I'll try to find out if there is a way to achieve CJK compatibility - I'll have to try to get in touch with JetBrains to find out, I'm not sure how long it may take for them to respond.

[udreams]

I've also been investigating this issue and wanted to share my findings. After reviewing the JBTerminalWidget documentation, I noticed there's no explicit mention of CJK character width calculation support in the component.

I tried two approaches to work around this:

1. First, I looked at the alternative implementation used in JetBrains' official MicroPython plugin (source) which uses ShellTerminalWidget instead. However, after switching to ShellTerminalWidget, the issue persisted.

2. Then I attempted enabling AutoWrap mode programmatically with:

setModeEnabled(TerminalMode.AutoWrap, true);

But unfortunately this didn't resolve the character truncation either.

These findings suggest the issue might be deeper in the terminal rendering stack. I found a relevant ticket on YouTrack (IJPL-104924) where other users have reported identical problems with CJK character truncation in the built-in terminal. This suggests it's a known platform-level issue affecting multiple JetBrains products.

The character truncation significantly impacts debugging workflows:

• Forces use of external terminals (like Xshell) for CJK text
• Requires English-only logging as workaround
• Still fails when receiving Chinese debug messages
• Critical information gets truncated during crucial debugging sessions

While we can mitigate by using English outputs, the core issue remains unresolved when handling CJK system responses - a fundamental limitation that needs JetBrains' attention.

[lukaskremla]

Nice research!

Missing support for CJK characters isn't the first issue I've ran into with the JBTerminalWidget - there are several other problems such as silent exceptions, random crashes that need scrappy workarounds, it seems that the terminal can overflow under certain circumstances with lots of output...

I'd like to get rid of it some way.

I have noticed that a different terminal element seems to be used through out the IDE - for example when executing python scripts and many other run configurations.

I haven't yet searched through the IntelliJ IDE source code to see how these are implemented, but I'm hoping that some different terminal could be implemented without having to handle too much of the UI myself and without unreasonably complicating the integration with the existing device communication logic

[udreams]

Based on your suggestion, I've fixed the issue and submitted a PR (#63)—line wrapping now works correctly. However, the REPL shortcuts (Ctrl+A/B/C/D/E) are not functioning. Could you help resolve this? Thanks!

[lukaskremla]

Thank you for the initiative.

Unfortunately switching to ConsoleViewImpl would break more things than it would fix. I've gone into some more detail in the PR.

I will get in touch with JetBrains to see what can be done to add support for CJK characters.