Python Textual app doesn't work properly on MSYS2 run through Command Prompt after 'msys2-runtime' update to >3.5.7-2-x86_64

[tieneupin]

My team have been running a Python Textual app in MSYS2's UCRT64 environment through a Command Prompt terminal. We had to use the Command Prompt terminal instead of the default mintty because the Textual app could not be clicked when run in a mintty termnial.

However, the recent msys2-runtime package update to >3.5.7-2-x86_64 has caused the app to glitch out when switching to a new screen. Instead of displaying a screen, it prints out characters according to mouse movement within the console window area.

Understanding what changed between version 3.5.7-2-x86_64 and 3.5.7-4-x86_64 and seeing what can be done to resolve it would be very appreciated.

(Additional context below)

The Problem:

• When running our app using MSYS2's default mintty terminal, we can't click on any of the buttons in the console.
• This behaviour is present across the wide range of Windows 10 versions we work with (Windows 10 Server 2016 & 2019, Windows 10 Professional & Home).
• This is unique to Windows 10, as users on the MSYS2 Discord channel have not been able to replicate the issue on Windows 11.
• This problem is not present in Cygwin's mintty terminal on these same Windows 10 versions; the Textual app's buttons all work as intended.
• These are externally managed PCs, so updating them is out of the question.

What We've Tried So Far:

• This problem does not occur when MSYS2 is run via Windows Terminal.
  • It is not supported for the Windows 10 versions present on the PCs we manage, so it is not a viable solution.
• We found a workaround where we run an MSYS2 session in a Command Prompt console.
  • This involved creating a Command Prompt shortcut and pointing to MSYS2 in the "Target" field as follows: cmd.exe /k "C:\msys64\msys2_shell.cmd -defterm -no-start -ucrt64 -shell bash".
  • The Textual app runs in that case; the buttons are clickable, although the UI occasionally displays funny characters.
• Updating msys2-runtime to >3.5.7-2-x86_64 causes this Command Prompt console workaround to fail.

[jeremyd2019]

Can you test the forthcoming 3.6.0 from #260 ? download the install.zip artifact from https://github.com/msys2/msys2-runtime/actions/runs/13929126975?pr=260 and extract usr/bin/msys-2.0.dll, replacing your msys64/usr/bin/msys-2.0.dll (backing up the old one first of course to put back when done).

[tieneupin]

@jeremyd2019 , thanks for responding so quickly.

Yes, I have time to perform the test now.

Other than replacing the .dll, will I need to do anything like upgrading the msys2-runtime package using pacman -S msys2-runtime from within the terminal environment?

[jeremyd2019]

Other than replacing the .dll, will I need to do anything like upgrading the msys2-runtime package using pacman -S msys2-runtime from within the terminal environment?

no.

Also, are you sure that it is msys2-runtime causing the issue (have you tried downgrading just it)? I think there was an ncurses update that caused some strange behavior with mouse input.

[tieneupin]

Also, are you sure that it is msys2-runtime causing the issue (have you tried downgrading just it)? I think there was an ncurses update that caused some strange behavior with mouse input.

Yes, I can confirm that downgrading msys2-runtime alone fixed the issue. I ran pacman -Syu last week to get all the up-to-date core packages before encountering this issue.

This would be my packages list at the moment, if that helps with troubleshooting:

base 2022.06-1
base-devel 2024.11-1
bash 5.2.037-2
bash-completion 2.16.0-1
binutils 2.44-1
bison 3.8.2-5
brotli 1.1.0-1
bsdtar 3.7.7-1
bzip2 1.0.8-4
ca-certificates 20241223-1
coreutils 8.32-5
curl 8.12.1-1
dash 0.5.12-1
db 6.2.32-5
diffstat 1.67-1
diffutils 3.11-1
dos2unix 7.5.2-1
file 5.46-1
filesystem 2025.02.23-1
findutils 4.10.0-2
flex 2.6.4-4
gawk 5.3.1-1
gcc-libs 13.3.0-1
gdbm 1.24-1
getent 2.18.90-5
gettext 0.22.5-1
git 2.48.1-1
gmp 6.3.0-1
gnupg 2.4.7-1
grep 1~3.0-7
gzip 1.13-1
heimdal 7.8.0-5
heimdal-libs 7.8.0-5
inetutils 2.5-2
info 7.1.1-1
less 668-1
libargp 20241207-1
libasprintf 0.22.5-1
libassuan 2.5.7-1
libbz2 1.0.8-4
libcbor 0.11.0-1
libcurl 8.12.1-1
libdb 6.2.32-5
libedit 20240808_3.1-1
libexpat 2.6.4-1
libffi 3.4.7-1
libfido2 1.15.0-1
libgcrypt 1.11.0-1
libgdbm 1.24-1
libgettextpo 0.22.5-1
libgnutls 3.8.9-1
libgpg-error 1.51-1
libhogweed 3.10.1-1
libiconv 1.18-1
libidn2 2.3.7-1
libintl 0.22.5-1
libksba 1.6.7-1
liblz4 1.10.0-1
liblzma 5.6.4-1
libnettle 3.10.1-1
libnghttp2 1.64.0-1
libnpth 1.8-1
libopenssl 3.4.1-1
libp11-kit 0.25.5-2
libpcre 8.45-5
libpcre2_8 10.44-1
libpsl 0.21.5-2
libreadline 8.2.013-1
libsqlite 3.46.1-1
libssh2 1.11.1-1
libtasn1 4.20.0-1
libunistring 1.3-1
libutil-linux 2.40.2-2
libxcrypt 4.4.38-1
libxxhash 0.8.3-1
libzstd 1.5.7-1
m4 1.4.19-2
make 4.4.1-2
mingw-w64-ucrt-x86_64-binutils 2.44-1
mingw-w64-ucrt-x86_64-bzip2 1.0.8-3
mingw-w64-ucrt-x86_64-crt-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-expat 2.7.0-1
mingw-w64-ucrt-x86_64-gcc 14.2.0-3
mingw-w64-ucrt-x86_64-gcc-libs 14.2.0-3
mingw-w64-ucrt-x86_64-gdb 16.2-1
mingw-w64-ucrt-x86_64-gdb-multiarch 16.2-1
mingw-w64-ucrt-x86_64-gettext-runtime 0.24-1
mingw-w64-ucrt-x86_64-gmp 6.3.0-2
mingw-w64-ucrt-x86_64-headers-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-isl 0.27-1
mingw-w64-ucrt-x86_64-libffi 3.4.7-1
mingw-w64-ucrt-x86_64-libiconv 1.18-1
mingw-w64-ucrt-x86_64-libmangle-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-libsystre 1.0.1-6
mingw-w64-ucrt-x86_64-libtre 0.9.0-1
mingw-w64-ucrt-x86_64-libwinpthread-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-libxml2 2.12.10-1
mingw-w64-ucrt-x86_64-make 4.4.1-3
mingw-w64-ucrt-x86_64-mpc 1.3.1-2
mingw-w64-ucrt-x86_64-mpdecimal 4.0.0-1
mingw-w64-ucrt-x86_64-mpfr 4.2.1-2
mingw-w64-ucrt-x86_64-ncurses 6.5.20241228-3
mingw-w64-ucrt-x86_64-openssl 3.4.1-1
mingw-w64-ucrt-x86_64-pkgconf 1~2.3.0-1
mingw-w64-ucrt-x86_64-python 3.12.9-3
mingw-w64-ucrt-x86_64-python-distlib 0.3.9-1
mingw-w64-ucrt-x86_64-python-pip 25.0.1-1
mingw-w64-ucrt-x86_64-python-setuptools 75.8.0-1
mingw-w64-ucrt-x86_64-readline 8.2.013-1
mingw-w64-ucrt-x86_64-rust 1.85.0-1
mingw-w64-ucrt-x86_64-sqlite3 3.47.2-1
mingw-w64-ucrt-x86_64-tcl 8.6.13-1
mingw-w64-ucrt-x86_64-termcap 1.3.1-7
mingw-w64-ucrt-x86_64-tk 8.6.13-1
mingw-w64-ucrt-x86_64-tools-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-tzdata 2025a-1
mingw-w64-ucrt-x86_64-windows-default-manifest 6.4-4
mingw-w64-ucrt-x86_64-winpthreads-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-winstorecompat-git 12.0.0.r576.g49111ba98-1
mingw-w64-ucrt-x86_64-xxhash 0.8.3-1
mingw-w64-ucrt-x86_64-xz 5.6.4-1
mingw-w64-ucrt-x86_64-zlib 1.3.1-1
mingw-w64-ucrt-x86_64-zstd 1.5.7-1
mintty 1~3.7.7-2
mpfr 4.2.1-1
msys2-keyring 1~20250214-1
msys2-launcher 1.5-3
msys2-runtime 3.5.7-2
nano 8.3-1
ncurses 6.5.20240831-2
nettle 3.10.1-1
openssh 9.9p2-1
openssl 3.4.1-1
p11-kit 0.25.5-2
pacman 6.1.0-11
pacman-contrib 1.10.6-1
pacman-mirrors 20250220-1
patch 2.7.6-3
perl 5.38.2-3
perl-Authen-SASL 2.1700-1
perl-Clone 0.47-1
perl-Convert-BinHex 1.125-2
perl-Encode-Locale 1.05-2
perl-Error 0.17030-1
perl-File-Listing 6.16-1
perl-HTML-Parser 3.83-1
perl-HTML-Tagset 3.24-1
perl-HTTP-Cookies 6.11-1
perl-HTTP-Daemon 6.16-1
perl-HTTP-Date 6.06-1
perl-HTTP-Message 7.00-1
perl-HTTP-Negotiate 6.01-3
perl-IO-HTML 1.004-2
perl-IO-Socket-SSL 2.089-1
perl-IO-Stringy 2.113-2
perl-LWP-MediaTypes 6.04-2
perl-MIME-tools 5.515-1
perl-MailTools 2.22-1
perl-Net-HTTP 6.23-1
perl-Net-SMTP-SSL 1.04-2
perl-Net-SSLeay 1.94-2
perl-TermReadKey 2.38-6
perl-TimeDate 2.33-2
perl-Try-Tiny 0.32-1
perl-URI 5.31-1
perl-WWW-RobotRules 6.02-3
perl-http-cookiejar 0.014-1
perl-libwww 6.78-1
pinentry 1.3.1-1
rebase 4.5.0-4
rsync 3.4.1-1
sed 4.9-1
tar 1.35-2
texinfo 7.1.1-1
texinfo-tex 7.1.1-1
time 1.9-3
tzcode 2025a-1
util-linux 2.40.2-2
vim 9.1.1006-2
wget 1.25.0-1
which 2.21-4
xz 5.6.4-1
zlib 1.3.1-1
zstd 1.5.7-1

[tieneupin]

OK, I've extracted the new .dll file correctly, and have tried running the Textual app again.

In the default mintty it remains unclickable, although keyboard shortcuts (like 'Q' to quit the app) work. This has not changed from previously observed behaviour.

It's the same as reported in the original message above when running it in Command Prompt.

[jeremyd2019]

For mintty, I've run into issues even on Cygwin where there seems to be an invisible window covering part of the screen, absorbing clicks. I don't know what causes it, I use Windows Terminal personally.

For the command prompt thing. So you're saying 3.5.7-2 works, 3.5.7-3 & -4 and 3.6.0 fail? That suggests cd64230

[jeremyd2019]

@tyan0 do you have any ideas? I'm not feeling well today, and I'm not 100% sure I understand this report.

[tyan0]

@tieneupin, if you could provide simple test case, it would be very helpful.

Is your Python Textual app running under:
mingw-w64-ucrt-x86_64-python 3.12.9-3
?

[tyan0]

I tried calculator demo (https://textual.textualize.io/#__tabbed_2_1), but it works as expected in command prompt.
The issue could not be reproduced. Clicking "7" button by mouse works.

$ pacman -Q msys2-runtime
msys2-runtime 3.5.7-4
$ uname -a
MSYS_NT-10.0-19045 HP-Z230 3.5.7-2644508f.x86_64 2025-03-11 08:33 UTC x86_64 Msys
$ /ucrt64/bin/python calculator.py

[tieneupin]

@tyan0, @jeremyd2019 , thanks for the troubleshooting support thus far!

Yes, I will try and put together a working example that reproduces the problem that I am facing. It will take a while though, as the textual app we use reads from configuration files and makes API calls quite extensively that I will have to mock out.

You're quite right, though, in that not all of the buttons are broken in the new MSYS2 runtime. Our app, when run through Command Prompt, works as intended partway until one particular block of logic where it brings up a new screen, at which point the app crashes and we get a wall of random characters.

[tieneupin]

I've been able to make some progress on this issue (haven't written a working example yet):

One of our buttons triggers the running of a Python subprocess that runs rsync. It's this subprocess that causes the Textual app to break, as commenting out this subprocess fixes the issue on the latest version of msys2-runtime.

Other parts of our app run rsync tasks as Python threads instead, which seems to work fine.

The fix for us might be to convert the subprocess instance into a thread, and it will most likely work with the latest msys2-runtime version.

I will try and convert it to a thread, and report back on whether this has resolved the issue.

[jeremyd2019]

ok, so that makes some sense in the context of cd64230, which deals with switching the console back and forth between Cygwin and native processes. You start from bash (Cygwin), you run ucrt64 python (native), then that runs rsync (Cygwin). Perhaps there's some case there that doesn't restore the console back to 'native' mode?

[tieneupin]

Yes, that seems to be the most likely case. Our rsync subprocess is dead simple, so I don't know if we can fix it from our end. 🤣

import subprocess

src_path: str
rsync_module_name: str
dst_path: str

# Set up rsync command
rsync_cmd = [
    "rsync",
    f"{src_path}",
    f"{rsync_module_name}/{dst_path}",
]

# Encase in bash shell
cmd = ["bash", "-c", " ".join(rsync_cmd)]

# Run rsync subprocess (commenting out subprocess.run() fixed the issue)
process = subprocess.run(cmd)
if process.returncode:
    log.warning(
        f"File(s) not successfully transferred to destination"
    )