Add LSP support (#68) [paid versions of IDEA only]

Author: JojOatXGME

CHANGELOG.md

@@ -4,6 +4,9 @@
 
 ### Added
 
+- Experimental Language Server support using IDEA's LSP API (#68)  
+  [(Only works for paid versions of IDEA :disappointed:)](https://blog.jetbrains.com/platform/2023/07/lsp-for-plugin-developers/#supported-ides)
+
 ### Changed
 
 ### Deprecated

build.gradle.kts

@@ -1,6 +1,7 @@
 import org.jetbrains.changelog.Changelog
 import org.jetbrains.changelog.markdownToHTML
-import org.jetbrains.intellij.tasks.RunPluginVerifierTask
+import org.jetbrains.intellij.tasks.RunPluginVerifierTask.FailureLevel
+import java.util.EnumSet
 
 plugins {
     id("java")
@@ -165,7 +166,7 @@ tasks {
     }
 
     runPluginVerifier {
-        failureLevel = RunPluginVerifierTask.FailureLevel.ALL
+        failureLevel = EnumSet.complementOf(EnumSet.of(FailureLevel.EXPERIMENTAL_API_USAGES))
         // Version 1.364 seems to be broken and always complains about supposedly missing 'plugin.xml':
         // https://youtrack.jetbrains.com/issue/MP-6388
         verifierVersion = "1.307"

gradle.properties

@@ -4,11 +4,12 @@
 pluginGroup = org.nixos.idea
 pluginName = NixIDEA
 pluginVersion = 0.4.0.13
-pluginSinceBuild = 231
+pluginSinceBuild = 232
 pluginUntilBuild = 241.*
 
-platformType = IC
-platformVersion = 2023.1.6
+platformType = IU
+# TODO Revert to 2023.2.6?
+platformVersion = 2024.1
 
 # Gradle Configuration
 # -> https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_configuration_properties

src/main/java/org/nixos/idea/lsp/NixLspServerDescriptor.java

@@ -0,0 +1,26 @@
+package org.nixos.idea.lsp;
+
+import com.intellij.execution.ExecutionException;
+import com.intellij.execution.configurations.GeneralCommandLine;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.platform.lsp.api.ProjectWideLspServerDescriptor;
+import org.jetbrains.annotations.NotNull;
+import org.nixos.idea.file.NixFileType;
+
+@SuppressWarnings("UnstableApiUsage")
+final class NixLspServerDescriptor extends ProjectWideLspServerDescriptor {
+    NixLspServerDescriptor(@NotNull Project project) {
+        super(project, "Nix");
+    }
+
+    @Override
+    public @NotNull GeneralCommandLine createCommandLine() throws ExecutionException {
+        return new GeneralCommandLine("nix", "--extra-experimental-features", "nix-command", "--extra-experimental-features", "flakes", "run", "nixpkgs#nil");
+    }
+
+    @Override
+    public boolean isSupportedFile(@NotNull VirtualFile virtualFile) {
+        return virtualFile.getFileType() == NixFileType.INSTANCE;
+    }
+}

src/main/java/org/nixos/idea/lsp/NixLspServerSupportProvider.java

@@ -0,0 +1,26 @@
+package org.nixos.idea.lsp;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.platform.lsp.api.LspServer;
+import com.intellij.platform.lsp.api.LspServerSupportProvider;
+import com.intellij.platform.lsp.api.lsWidget.LspServerWidgetItem;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.nixos.idea.file.NixFileType;
+import org.nixos.idea.icon.NixIcons;
+
+@SuppressWarnings("UnstableApiUsage")
+public final class NixLspServerSupportProvider implements LspServerSupportProvider {
+    @Override
+    public void fileOpened(@NotNull Project project, @NotNull VirtualFile virtualFile, @NotNull LspServerStarter lspServerStarter) {
+        if (virtualFile.getFileType() == NixFileType.INSTANCE) {
+            lspServerStarter.ensureServerStarted(new NixLspServerDescriptor(project));
+        }
+    }
+
+    @Override
+    public @NotNull LspServerWidgetItem createLspServerWidgetItem(@NotNull LspServer lspServer, @Nullable VirtualFile currentFile) {
+        return new LspServerWidgetItem(lspServer, currentFile, NixIcons.FILE, null);
+    }
+}

src/main/resources/META-INF/plugin.xml

@@ -5,6 +5,7 @@
     <vendor>NixOS</vendor>
 
     <depends>com.intellij.modules.lang</depends>
+    <depends>com.intellij.modules.platform</depends>
 
     <extensions defaultExtensionNs="com.intellij">
 
@@ -46,6 +47,9 @@
         <colorSettingsPage
                 implementation="org.nixos.idea.settings.NixColorSettingsPage" />
 
+        <platform.lsp.serverSupportProvider
+                implementation="org.nixos.idea.lsp.NixLspServerSupportProvider"/>
+
     </extensions>
 
 </idea-plugin>