Rider/C# - Formatting actions have no effect

[actforjason]

Checklist

• I am able to reproduce the bug with the latest version
• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.

Affected version

save-actions 1.5.0，Rider 2025.2.0.1

Description of the problem

The file is saved but not formatted with Save All.

Steps to reproduce the bug

Settings are as follows,

Additional information

No response

[AB-xdev]

Thank you for the issue, I can reproduce the problem with Rider.

So the problem here is that in https://github.com/JetBrains/intellij-community/blob/64124b0ee1ab4cab228051dcbd4455eef2097464/platform/lang-impl/src/com/intellij/codeInsight/actions/AbstractLayoutCodeProcessor.java#L339 LanguageFormatting.INSTANCE.forContext(psiFile) always returns null for C#.

It looks like there is a problem with Rider's definition of C# as it's not registered as a language inside the IDE?
There are no extension points for C# in com.intellij.lang.formatter and com.intellij.metaLanguage.

Also running Reformat code (Ctrl + Alt + L) in Rider does not trigger the ReformatCodeProcessor.

There is also no Reformat code action present in Actions on Save just a custom one called Reformat code and cleanup:

Rider source code is also not publicly available (and written in Kotlin so I can't decompile it properly), so it's kind of hard to say what's going on in there...

[AB-xdev]

The other formatting options like Optimize imports and Rearrange fields... also don't seem to work...

[AB-xdev]

I reported the problem to JetBrains: https://youtrack.jetbrains.com/issue/RIDER-129474