Add DABs LSP language client for deployment-aware features

Introduces a BundleLSPClient that spawns `databricks bundle lsp` via
stdio to provide deployment-aware features for bundle YAML files:

- Document links: Ctrl+click on resource keys to open in workspace
- Hover: Shows resource ID, name, and workspace link

The client connects to the CLI's new hidden LSP server and activates
for all bundle YAML files (databricks.yml, databricks.yaml, etc.).
Stacks with the existing Red Hat YAML extension.

Depends on: databricks/cli#4714

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: shreyas-goenka

packages/databricks-vscode/package.json

@@ -1201,6 +1201,7 @@
         "minimatch": "^10.0.1",
         "shell-quote": "^1.8.1",
         "triple-beam": "^1.4.1",
+        "vscode-languageclient": "^9.0.1",
         "winston": "^3.11.0",
         "yaml": "^2.3.4"
     },

packages/databricks-vscode/src/bundle/BundleLSPClient.ts

@@ -0,0 +1,93 @@
+import {
+    LanguageClient,
+    LanguageClientOptions,
+    ServerOptions,
+} from "vscode-languageclient/node";
+import {Disposable, Uri, workspace} from "vscode";
+import {CliWrapper} from "../cli/CliWrapper";
+
+/**
+ * Manages the lifecycle of the DABs Language Server Protocol client.
+ * Spawns `databricks bundle lsp` and connects via stdio to provide
+ * deployment-aware features (document links, hover) for bundle YAML files.
+ */
+export class BundleLSPClient implements Disposable {
+    private client: LanguageClient | undefined;
+    private readonly cli: CliWrapper;
+
+    constructor(cli: CliWrapper) {
+        this.cli = cli;
+    }
+
+    async start(workspaceFolder: Uri, target?: string): Promise<void> {
+        // Stop existing client if running.
+        await this.stop();
+
+        const args = ["bundle", "lsp"];
+        if (target) {
+            args.push("--target", target);
+        }
+
+        const serverOptions: ServerOptions = {
+            command: this.cli.cliPath,
+            args: args,
+            options: {
+                cwd: workspaceFolder.fsPath,
+            },
+        };
+
+        const clientOptions: LanguageClientOptions = {
+            documentSelector: [
+                {
+                    scheme: "file",
+                    language: "yaml",
+                    pattern: "**/databricks.yml",
+                },
+                {
+                    scheme: "file",
+                    language: "yaml",
+                    pattern: "**/databricks.yaml",
+                },
+                {
+                    scheme: "file",
+                    language: "yaml",
+                    pattern: "**/bundle.yml",
+                },
+                {
+                    scheme: "file",
+                    language: "yaml",
+                    pattern: "**/bundle.yaml",
+                },
+            ],
+            workspaceFolder: {
+                uri: workspaceFolder,
+                name: workspace.name ?? "workspace",
+                index: 0,
+            },
+        };
+
+        this.client = new LanguageClient(
+            "databricks-bundle-lsp",
+            "Databricks Bundle LSP",
+            serverOptions,
+            clientOptions
+        );
+
+        await this.client.start();
+    }
+
+    async stop(): Promise<void> {
+        if (this.client) {
+            try {
+                await this.client.stop();
+            } catch {
+                // Client may already be stopped.
+            }
+            this.client = undefined;
+        }
+    }
+
+    dispose(): void {
+        this.stop();
+    }
+}

packages/databricks-vscode/src/extension.ts

@@ -50,6 +50,7 @@ import {
     BundleFileSet,
     registerBundleAutocompleteProvider,
 } from "./bundle";
+import {BundleLSPClient} from "./bundle/BundleLSPClient";
 import {showWhatsNewPopup} from "./whatsNewPopup";
 import {BundleValidateModel} from "./bundle/models/BundleValidateModel";
 import {ConfigModel} from "./configuration/models/ConfigModel";
@@ -890,6 +891,20 @@ export async function activate(
         );
     });
 
+    // Start the DABs LSP client for deployment-aware features (document links, hover).
+    const bundleLSPClient = new BundleLSPClient(cli);
+    context.subscriptions.push(bundleLSPClient);
+
+    const workspaceFolder = workspace.workspaceFolders?.[0]?.uri;
+    if (workspaceFolder) {
+        bundleLSPClient.start(workspaceFolder).catch((e) => {
+            logging.NamedLogger.getOrCreate(Loggers.Extension).error(
+                "Failed to start bundle LSP: ",
+                e
+            );
+        });
+    }
+
     setDbnbCellLimits(workspaceFolderManager, connectionManager).catch((e) => {
         logging.NamedLogger.getOrCreate(Loggers.Extension).error(
             "Error while setting jupyter configs for parsing databricks notebooks",

yarn.lock

@@ -3799,6 +3799,7 @@ __metadata:
     ts-node: ^10.9.2
     typescript: ^5.3.3
     vsce: ^2.15.0
+    vscode-languageclient: ^9.0.1
     wdio-video-reporter: ^5.1.4
     wdio-vscode-service: ^6.0.2
     winston: ^3.11.0
@@ -9520,6 +9521,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"semver@npm:^7.3.7":
+  version: 7.7.4
+  resolution: "semver@npm:7.7.4"
+  bin:
+    semver: bin/semver.js
+  checksum: 9b4a6a58e98b9723fafcafa393c9d4e8edefaa60b8dfbe39e30892a3604cf1f45f52df9cfb1ae1a22b44c8b3d57fec8a9bb7b3e1645431587cb272399ede152e
+  languageName: node
+  linkType: hard
+
 "semver@npm:^7.5.2, semver@npm:^7.5.4":
   version: 7.5.4
   resolution: "semver@npm:7.5.4"
@@ -10840,6 +10850,41 @@ __metadata:
   languageName: node
   linkType: hard
 
+"vscode-jsonrpc@npm:8.2.0":
+  version: 8.2.0
+  resolution: "vscode-jsonrpc@npm:8.2.0"
+  checksum: f302a01e59272adc1ae6494581fa31c15499f9278df76366e3b97b2236c7c53ebfc71efbace9041cfd2caa7f91675b9e56f2407871a1b3c7f760a2e2ee61484a
+  languageName: node
+  linkType: hard
+
+"vscode-languageclient@npm:^9.0.1":
+  version: 9.0.1
+  resolution: "vscode-languageclient@npm:9.0.1"
+  dependencies:
+    minimatch: ^5.1.0
+    semver: ^7.3.7
+    vscode-languageserver-protocol: 3.17.5
+  checksum: ff30e5a9aac6726a88fe443fd631fe7e6130225299667c13162547f0a13ca2548d3f277d68cfb3ef6dc1810c048b2cf0e05024e1bcbd11982cd8acf681a67873
+  languageName: node
+  linkType: hard
+
+"vscode-languageserver-protocol@npm:3.17.5":
+  version: 3.17.5
+  resolution: "vscode-languageserver-protocol@npm:3.17.5"
+  dependencies:
+    vscode-jsonrpc: 8.2.0
+    vscode-languageserver-types: 3.17.5
+  checksum: dfb42d276df5dfea728267885b99872ecff62f6c20448b8539fae71bb196b420f5351c5aca7c1047bf8fb1f89fa94a961dce2bc5bf7e726198f4be0bb86a1e71
+  languageName: node
+  linkType: hard
+
+"vscode-languageserver-types@npm:3.17.5":
+  version: 3.17.5
+  resolution: "vscode-languageserver-types@npm:3.17.5"
+  checksum: 79b420e7576398d396579ca3a461c9ed70e78db4403cd28bbdf4d3ed2b66a2b4114031172e51fad49f0baa60a2180132d7cb2ea35aa3157d7af3c325528210ac
+  languageName: node
+  linkType: hard
+
 "vscode-uri@npm:^3.0.8":
   version: 3.0.8
   resolution: "vscode-uri@npm:3.0.8"