[Bug]: Rider plugin not able to install csharpier

[aomader]

Description

It seems that the JetBrains Rider plugin is not able to install, and thus not able to invoke, the csharpier tool.

Relevant parts from the log file:

2026-09-10 08:48:19,781 [ 111037]   FINE - #c.i.c.CSharpierLogger - Running /usr/local/share/dotnet/dotnet tool install csharpier --version 1.3.0 --tool-path /Users/XXX/.cache/csharpier/1.3.0/arm64 in /Users/XXX/YYY
2026-09-10 08:48:21,372 [ 112628] SEVERE - #c.j.r.p.c.s.f.SecurityHelper - Path isn't allowed in settings file name: $APP_CONFIG$/CSharpierPlugin.xml
java.lang.Throwable: Path isn't allowed in settings file name: $APP_CONFIG$/CSharpierPlugin.xml
	at com.intellij.openapi.diagnostic.Logger.error(Logger.java:378)
	at com.jetbrains.rd.platform.codeWithMe.settings.fileBasedSync.SecurityHelper.validateSettingsFile(SecurityHelper.kt:29)
	at com.jetbrains.rdserver.settings.fileBasedSync.BackendFileBasedSettingsSyncService.readSettingsFile(BackendFileBasedSettingsSyncService.kt:216)
	at com.jetbrains.rdserver.settings.fileBasedSync.BackendFileBasedSettingsSyncService$requestSettingsFile$1.invokeSuspend(BackendFileBasedSettingsSyncService.kt:294)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:34)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:100)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:610)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runDefaultDispatcherTask(CoroutineScheduler.kt:1194)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:906)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:775)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:762)

2026-09-10 08:48:29,205 [ 120461]   FINE - #c.i.c.CSharpierLogger - Running /Users/XXX/.cache/csharpier/1.3.0/arm64/csharpier --version in /Users/XXX/.cache/csharpier/1.3.0/arm64
2026-09-10 08:48:29,209 [ 120465] SEVERE - #c.i.c.CSharpierLogger - Cannot run program "/Users/XXX/.cache/csharpier/1.3.0/arm64/csharpier" (in directory "/Users/XXX/.cache/csharpier/1.3.0/arm64"): Exec failed, error: 2 (No such file or directory) 
java.io.IOException: Cannot run program "/Users/XXX/.cache/csharpier/1.3.0/arm64/csharpier" (in directory "/Users/XXX/.cache/csharpier/1.3.0/arm64"): Exec failed, error: 2 (No such file or directory) 
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1112)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1046)
	at com.intellij.csharpier.ProcessHelper.executeCommand(ProcessHelper.java:34)
	at com.intellij.csharpier.CustomPathInstaller.validateInstall(CustomPathInstaller.java:71)
	at com.intellij.csharpier.CustomPathInstaller.ensureVersionInstalled(CustomPathInstaller.java:61)
	at com.intellij.csharpier.CSharpierProcessProvider.setupCSharpierProcess(CSharpierProcessProvider.java:261)
	at com.intellij.csharpier.CSharpierProcessProvider.lambda$findAndWarmProcess$0(CSharpierProcessProvider.java:96)
	at java.base/java.lang.Thread.run(Thread.java:1474)
Caused by: java.io.IOException: Exec failed, error: 2 (No such file or directory) 
	at java.base/java.lang.ProcessImpl.forkAndExec(Native Method)
	at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:300)
	at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:231)
	at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1078)
	... 7 more
2026-09-10 08:48:29,209 [ 120465] SEVERE - #c.i.c.CSharpierLogger - JetBrains Rider 2026.2.1  Build #RD-262.9437.287
2026-09-10 08:48:29,209 [ 120465] SEVERE - #c.i.c.CSharpierLogger - JDK: 25.0.3; VM: OpenJDK 64-Bit Server VM; Vendor: JetBrains s.r.o.
2026-09-10 08:48:29,209 [ 120465] SEVERE - #c.i.c.CSharpierLogger - OS: Mac OS X
2026-09-10 08:48:29,210 [ 120466] SEVERE - #c.i.c.CSharpierLogger - Plugin to blame: csharpier version: 10.0.6

Steps to Reproduce

Environment:

• .NET SDK 10.0.12
• CSharpier Rider Plugin 10.0.6
• Rider 2026.2.1

Steps:
Just save a file to get it formatted.

Expected Behavior

The file being formatted.

Actual Behavior

The plugin tells me via a popup that it cannot format the source code and that I should check the logs.

[belav]

It appears that the csharpier dotnet tool did not install correctly. There are some troubleshooting steps that may help. If they don't, then can you enable debug logging and get me the full log output?

I did create #1917 based on the first log entry, I haven't seen that before and it sounds like Rider may have changed where setting files are allowed.

[aomader]

Yeah, I already installed it manually with the help of that page, thank you.