Add command to create a Swift DocC documentation catalog

package.json

@@ -489,6 +489,11 @@
         "command": "swift.generateSourcekitConfiguration",
         "title": "Generate SourceKit-LSP Configuration",
         "category": "Swift"
+      },
+      {
+        "command": "swift.createDocumentationCatalog",
+        "title": "Create Documentation Catalog",
+        "category": "Swift"
       }
     ],
     "configuration": [
@@ -1382,6 +1387,10 @@
         {
           "command": "swift.play",
           "when": "false"
+        },
+        {
+          "command": "swift.createDocumentationCatalog",
+          "when": "workspaceFolderCount > 0"
         }
       ],
       "editor/context": [

src/commands.ts

@@ -20,6 +20,7 @@ import { WorkspaceContext } from "./WorkspaceContext";
 import { attachDebugger } from "./commands/attachDebugger";
 import { cleanBuild, debugBuild, runBuild } from "./commands/build";
 import { captureDiagnostics } from "./commands/captureDiagnostics";
+import { createDocumentationCatalog } from "./commands/createDocumentationCatalog";
 import { createNewProject } from "./commands/createNewProject";
 import { editDependency } from "./commands/dependencies/edit";
 import { resolveDependencies } from "./commands/dependencies/resolve";
@@ -350,6 +351,10 @@ export function register(ctx: WorkspaceContext): vscode.Disposable[] {
             await vscode.commands.executeCommand("vscode.open", vscode.Uri.file(packagePath));
         }),
         vscode.commands.registerCommand("swift.openDocumentation", () => openDocumentation()),
+        vscode.commands.registerCommand(
+            "swift.createDocumentationCatalog",
+            async () => await createDocumentationCatalog(ctx)
+        ),
         vscode.commands.registerCommand(
             Commands.GENERATE_SOURCEKIT_CONFIG,
             async () => await generateSourcekitConfiguration(ctx)

src/commands/createDocumentationCatalog.ts

@@ -0,0 +1,138 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+import * as fs from "fs/promises";
+import * as path from "path";
+import * as vscode from "vscode";
+
+import { FolderContext } from "../FolderContext";
+import { WorkspaceContext } from "../WorkspaceContext";
+import { selectFolder } from "../ui/SelectFolderQuickPick";
+import { folderExists, pathExists } from "../utilities/filesystem";
+
+type DoccLocationPickItem = vscode.QuickPickItem & {
+    basePath: string;
+};
+
+export async function createDocumentationCatalog(
+    ctx: WorkspaceContext,
+    folderContext?: FolderContext
+): Promise<void> {
+    let folder = folderContext ?? ctx.currentFolder;
+
+    // ---- workspace folder resolution (standard pattern) ----
+    if (!folder) {
+        if (ctx.folders.length === 0) {
+            void vscode.window.showErrorMessage(
+                "Creating a documentation catalog requires an open workspace folder."
+            );
+            return;
+        }
+
+        if (ctx.folders.length === 1) {
+            folder = ctx.folders[0];
+        } else {
+            const selected = await selectFolder(
+                ctx,
+                "Select a workspace folder to create the DocC catalog in",
+                { all: "" }
+            );
+            if (selected.length !== 1) {
+                return;
+            }
+            folder = selected[0];
+        }
+    }
+
+    const rootPath = folder.folder.fsPath;
+
+    // ---- build QuickPick items from swiftPackage (PROMISE) ----
+    const itemsPromise = folder.swiftPackage.getTargets().then(async targets => {
+        const items: DoccLocationPickItem[] = [];
+
+        for (const target of targets) {
+            const base = path.join(rootPath, target.path);
+
+            // target paths must be directories → folderExists is correct here
+            if (await folderExists(base)) {
+                items.push({
+                    label: `Target: ${target.name}`,
+                    description: target.type,
+                    detail: target.path,
+                    basePath: base,
+                });
+            }
+        }
+
+        items.push({
+            label: "Standalone documentation catalog",
+            description: "Workspace root",
+            basePath: rootPath,
+        });
+
+        return items;
+    });
+
+    // ---- show QuickPick (toolchain-style pattern) ----
+    const selection = await vscode.window.showQuickPick(itemsPromise, {
+        title: "Create DocC Documentation Catalog",
+        placeHolder: "Select where to create the documentation catalog",
+        canPickMany: false,
+    });
+
+    if (!selection) {
+        return;
+    }
+
+    const basePath = selection.basePath;
+
+    // ---- module name input ----
+    const moduleName = await vscode.window.showInputBox({
+        prompt: "Enter Swift module name",
+        placeHolder: "MyModule",
+        validateInput: async value => {
+            const name = value.trim();
+            if (name.length === 0) {
+                return "Module name cannot be empty";
+            }
+
+            const doccDir = path.join(basePath, `${name}.docc`);
+
+            // creation path → must be unused → pathExists
+            if (await pathExists(doccDir)) {
+                return `Documentation catalog "${name}.docc" already exists`;
+            }
+
+            return undefined;
+        },
+    });
+
+    if (!moduleName) {
+        return;
+    }
+
+    const doccDir = path.join(basePath, `${moduleName}.docc`);
+    const markdownFile = path.join(doccDir, `${moduleName}.md`);
+
+    // ---- execution-time guard (race-safe) ----
+    if (await pathExists(doccDir)) {
+        void vscode.window.showErrorMessage(
+            `Documentation catalog "${moduleName}.docc" already exists`
+        );
+        return;
+    }
+
+    await fs.mkdir(doccDir);
+    await fs.writeFile(markdownFile, `# ${moduleName}\n`, "utf8");
+
+    void vscode.window.showInformationMessage(
+        `Created DocC documentation catalog: ${moduleName}.docc`
+    );
+}

test/integration-tests/commands/createDocumentationCatalog.test.ts

@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2025 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+import { expect } from "chai";
+import * as fs from "fs/promises";
+import * as path from "path";
+import * as sinon from "sinon";
+import * as vscode from "vscode";
+
+import { FolderContext } from "@src/FolderContext";
+import { WorkspaceContext } from "@src/WorkspaceContext";
+
+import { tag } from "../../tags";
+import { activateExtensionForSuite, folderInRootWorkspace } from "../utilities/testutilities";
+
+tag("large").suite("Create Documentation Catalog Command", function () {
+    let folderContext: FolderContext;
+    let workspaceContext: WorkspaceContext;
+
+    activateExtensionForSuite({
+        async setup(ctx) {
+            workspaceContext = ctx;
+            folderContext = await folderInRootWorkspace("defaultPackage", workspaceContext);
+            await workspaceContext.focusFolder(folderContext);
+        },
+    });
+
+    test("creates a DocC catalog for a SwiftPM target", async () => {
+        test("creates a DocC catalog for a SwiftPM target", async () => {
+            const quickPickStub = sinon.stub(vscode.window, "showQuickPick");
+            const inputBoxStub = sinon.stub(vscode.window, "showInputBox");
+
+            try {
+                inputBoxStub.resolves("MyModule");
+                quickPickStub.callsFake(async itemsOrPromise => {
+                    const items = await Promise.resolve(itemsOrPromise);
+                    return items.find(item => item.label.startsWith("Target:"));
+                });
+
+                await vscode.commands.executeCommand("swift.createDocumentationCatalog");
+                const basePath = folderContext.folder.fsPath;
+                const doccDir = path.join(basePath, "MyModule.docc");
+                const markdownFile = path.join(doccDir, "MyModule.md");
+
+                expect(await fs.stat(doccDir)).to.exist;
+                expect(await fs.stat(markdownFile)).to.exist;
+
+                const contents = await fs.readFile(markdownFile, "utf8");
+                expect(contents).to.contain("# MyModule");
+            } finally {
+                quickPickStub.restore();
+                inputBoxStub.restore();
+            }
+        });
+    });
+});