IJPL-227035 Eel, WSL, IJent: Remove wsl.use.remote.agent.for.nio.filesystem flag

This is a tiny step on the long way of making the WSL support a plugin.

GitOrigin-RevId: 5a25e5a9e030942eaba5ffbcb9216e456abc7b35

platform/build-scripts/src/org/jetbrains/intellij/build/impl/BuildContextImpl.kt

@@ -1,10 +1,8 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 @file:Suppress("ReplaceGetOrSet")
 
 package org.jetbrains.intellij.build.impl
 
-import com.intellij.platform.ijent.community.buildConstants.IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY
-import com.intellij.platform.ijent.community.buildConstants.MULTI_ROUTING_FILE_SYSTEM_VMOPTIONS
 import com.intellij.platform.ijent.community.buildConstants.isMultiRoutingFileSystemEnabledForProduct
 import com.intellij.platform.runtime.product.ProductMode
 import com.intellij.platform.runtime.product.serialization.ProductModulesSerialization
@@ -465,13 +463,6 @@ class BuildContextImpl internal constructor(
       jvmArgs.add("-Didea.platform.prefix=${productProperties.platformPrefix}")
     }
 
-    if (os == OsFamily.WINDOWS) {
-      jvmArgs.add("-D${IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY}=${useMultiRoutingFs}")
-      if (useMultiRoutingFs) {
-        jvmArgs.addAll(MULTI_ROUTING_FILE_SYSTEM_VMOPTIONS)
-      }
-    }
-
     jvmArgs.addAll(productProperties.additionalIdeJvmArguments)
     jvmArgs.addAll(productProperties.getAdditionalContextDependentIdeJvmArguments(this))
 

platform/ijent/buildConstants/src/com/intellij/platform/ijent/community/buildConstants/IjentBuildScriptsConstants.kt

@@ -1,4 +1,4 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 @file:Suppress("ReplaceJavaStaticMethodWithKotlinAnalog")
 
 package com.intellij.platform.ijent.community.buildConstants
@@ -39,8 +39,6 @@ private val MRFS_AND_IJENT_DISABLED_BY_DEFAULT_IN: Collection<String> = java.uti
 
 const val IJENT_BOOT_CLASSPATH_MODULE: String = "intellij.platform.core.nio.fs"
 
-const val IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY: String = "wsl.use.remote.agent.for.nio.filesystem"
-
 const val IJENT_REQUIRED_DEFAULT_NIO_FS_PROVIDER_CLASS: String = "com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider"
 
 val MULTI_ROUTING_FILE_SYSTEM_VMOPTIONS: List<String> = java.util.List.of(

platform/platform-impl/bootstrap/eel/src/com/intellij/platform/ide/bootstrap/eel/MultiRoutingFileSystemVmOptionsSetter.kt

@@ -1,16 +1,13 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.platform.ide.bootstrap.eel
 
 import com.intellij.diagnostic.VMOptions
 import com.intellij.execution.wsl.WslIjentAvailabilityService
 import com.intellij.openapi.application.ApplicationManager
-import com.intellij.openapi.application.ApplicationNamesInfo
 import com.intellij.openapi.application.PathManager
 import com.intellij.openapi.diagnostic.logger
 import com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider
 import com.intellij.platform.ijent.community.buildConstants.IJENT_BOOT_CLASSPATH_MODULE
-import com.intellij.platform.ijent.community.buildConstants.IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY
-import com.intellij.platform.ijent.community.buildConstants.isMultiRoutingFileSystemEnabledForProduct
 import org.jetbrains.annotations.VisibleForTesting
 import java.io.IOException
 import java.lang.management.ManagementFactory
@@ -22,7 +19,6 @@ object MultiRoutingFileSystemVmOptionsSetter {
   fun ensureInVmOptionsImpl(
     isEnabled: Boolean,
     forceProductionOptions: Boolean,
-    isEnabledByDefault: Boolean = isMultiRoutingFileSystemEnabledForProduct(ApplicationNamesInfo.getInstance().scriptName),
     getOptionByPrefix: (String) -> List<String>,
   ): Collection<Pair<String, String?>> {
     val changedOptions = mutableListOf<Pair<String, String?>>()
@@ -74,21 +70,6 @@ object MultiRoutingFileSystemVmOptionsSetter {
       }
     }
 
-    run {
-      val prefix = "-D$IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY="
-      val valueToSet = when (val actualValue = getOptionByPrefix(prefix).firstOrNull()?.toBooleanStrictOrNull()) {
-        null ->
-          if (isEnabled != isEnabledByDefault && changedOptions.isNotEmpty()) isEnabled
-          else null
-        true, false ->
-          if (isEnabled != actualValue) isEnabled
-          else null
-      }
-      if (valueToSet != null) {
-        changedOptions += prefix to valueToSet.toString()
-      }
-    }
-
     return changedOptions
   }
 

platform/platform-tests/testSrc/com/intellij/execution/wsl/MultiRoutingFileSystemVmOptionsSetterTest.kt

@@ -1,4 +1,4 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.execution.wsl
 
 import com.intellij.platform.ide.bootstrap.eel.MultiRoutingFileSystemVmOptionsSetter
@@ -19,87 +19,86 @@ class MultiRoutingFileSystemVmOptionsSetterTest {
 
   @Test
   fun `enable when no options set`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = true, forceProductionOptions = true, isEnabledByDefault = false, vmOptionsReader(""))
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = true, forceProductionOptions = true,
+        vmOptionsReader(""))
     changedOptions shouldMatch listOf(
       "-Djava.nio.file.spi.DefaultFileSystemProvider=com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider",
-      "-Dwsl.use.remote.agent.for.nio.filesystem=true",
     )
   }
 
   @Test
   fun `enable when no options set in unit test mode`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = true, forceProductionOptions = false, isEnabledByDefault = false, vmOptionsReader(""))
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = true, forceProductionOptions = false,
+        vmOptionsReader(""))
     changedOptions shouldMatch listOf(
       "-Djava.nio.file.spi.DefaultFileSystemProvider=com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider",
-      "-Dwsl.use.remote.agent.for.nio.filesystem=true",
       "-Xbootclasspath/a:out/classes/production/intellij.platform.core.nio.fs",
     )
   }
 
   @Test
   fun `disable when no options set and disabled by default`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true, isEnabledByDefault = false, vmOptionsReader(""))
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true,
+        vmOptionsReader(""))
     changedOptions shouldMatch listOf()
   }
 
   @Test
   fun `enable when disabling options set`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = true, forceProductionOptions = true, isEnabledByDefault = false, vmOptionsReader("""
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = true, forceProductionOptions = true,
+        vmOptionsReader("""
       -Didea.force.default.filesystem=true
       -Djava.nio.file.spi.DefaultFileSystemProvider=com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider
-      -Dwsl.use.remote.agent.for.nio.filesystem=false
     """.trimIndent()))
 
     changedOptions shouldMatch listOf(
       "-Didea.force.default.filesystem=false",
-      "-Dwsl.use.remote.agent.for.nio.filesystem=true",
     )
   }
 
   @Test
   fun `disable when enabling options set`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true, isEnabledByDefault = false, vmOptionsReader("""
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true,
+        vmOptionsReader("""
       -Djava.nio.file.spi.DefaultFileSystemProvider=com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider
-      -Dwsl.use.remote.agent.for.nio.filesystem=true
     """.trimIndent()))
 
     changedOptions shouldMatch listOf(
       "-Didea.force.default.filesystem=true",
-      "-Dwsl.use.remote.agent.for.nio.filesystem=false"
     )
   }
 
   @Test
   fun `disable when enabling options set and forcing unset`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true, isEnabledByDefault = false, vmOptionsReader("""
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true,
+        vmOptionsReader("""
         -Didea.force.default.filesystem=false
         -Djava.nio.file.spi.DefaultFileSystemProvider=com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider
-        -Dwsl.use.remote.agent.for.nio.filesystem=true
       """.trimIndent()))
 
     changedOptions shouldMatch listOf(
       "-Didea.force.default.filesystem=true",
-      "-Dwsl.use.remote.agent.for.nio.filesystem=false",
     )
   }
 
   /** This test checks that IJPL-158020 won't happen again when IJent WSL FS is enabled by default. */
   @Test
   fun `disable when no options set and enabled by default`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true, isEnabledByDefault = true, vmOptionsReader(""))
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true,
+        vmOptionsReader(""))
 
     changedOptions shouldMatch listOf()
   }
 
   @Test
   fun `enabled by default but disabled locally with enabling options in distribution vm options file`() {
-    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true, isEnabledByDefault = true, vmOptionsReader("""
+    val changedOptions = MultiRoutingFileSystemVmOptionsSetter.ensureInVmOptionsImpl(isEnabled = false, forceProductionOptions = true,
+        vmOptionsReader("""
       -Djava.nio.file.spi.DefaultFileSystemProvider=com.intellij.platform.core.nio.fs.MultiRoutingFileSystemProvider
     """.trimIndent()))
 
     changedOptions shouldMatch listOf(
       "-Didea.force.default.filesystem=true",
-      "-Dwsl.use.remote.agent.for.nio.filesystem=false",
     )
   }
 

plugins/devkit/devkit-core/src/run/DevKitApplicationPatcher.kt

@@ -1,4 +1,4 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package org.jetbrains.idea.devkit.run
 
 import com.intellij.execution.JavaRunConfigurationBase
@@ -21,7 +21,6 @@ import com.intellij.openapi.util.io.FileUtilRt
 import com.intellij.platform.eel.provider.asEelPath
 import com.intellij.platform.ijent.community.buildConstants.IJENT_BOOT_CLASSPATH_MODULE
 import com.intellij.platform.ijent.community.buildConstants.IJENT_REQUIRED_DEFAULT_NIO_FS_PROVIDER_CLASS
-import com.intellij.platform.ijent.community.buildConstants.IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY
 import com.intellij.platform.ijent.community.buildConstants.MULTI_ROUTING_FILE_SYSTEM_VMOPTIONS
 import com.intellij.util.PlatformUtils
 import com.intellij.util.lang.UrlClassLoader
@@ -279,7 +278,10 @@ internal fun enableIjentDefaultFsProvider(
       project = project,
       platformPrefix = vmParameters.getPropertyValue("idea.platform.prefix"),
     )
-    vmParameters.add("-D${IJENT_WSL_FILE_SYSTEM_REGISTRY_KEY}=$isIjentWslFsEnabled")
+
+    // This option doesn't exist anymore, but it used to exist in old versions.
+    vmParameters.add("-Dwsl.use.remote.agent.for.nio.filesystem=$isIjentWslFsEnabled")
+
     vmParameters.addAll(getMultiRoutingFileSystemVmOptions_Reflective(project))
 
     val outputRoot = getOutputByModule(project, IJENT_BOOT_CLASSPATH_MODULE, "ijent boot classpath addition")