feat: military grade commands synchronizer as esbuild plugin

esbuild.js

@@ -1,8 +1,81 @@
 const esbuild = require("esbuild");
+const fs = require("node:fs");
+const path = require("node:path");
 
 const production = process.argv.includes("--production");
 const watch = process.argv.includes("--watch");
 
+/**
+ * Needed by `syncCommandsPlugin`, which evaluates the commands, because `vscode` is not
+ * a real package. `vscode` imports only make sense in the extension host context. We can't
+ * just do `external: ["vscode"]` because we aren't bundling the extension in its host context.
+ *
+ * @type {import("esbuild").Plugin}
+ */
+const vscodeStubPlugin = {
+    name: "stub-vscode",
+
+    setup(build) {
+        build.onResolve({ filter: /^vscode$/ }, (args) => ({ path: args.path, namespace: "vscode-stub" }));
+        build.onLoad({ filter: /.*/, namespace: "vscode-stub" }, () => ({
+            loader: "js",
+            contents: `
+                function stub() {
+                    return new Proxy(function () {}, { get: stub, apply: stub, construct: stub });
+                }
+                module.exports = stub();
+            `,
+        }));
+    },
+};
+
+/**
+ * Rewrites package.json's `contributes.commands` based on `src/commands/index.ts`, to
+ * have a single source of truth.
+ *
+ * @type {import("esbuild").Plugin}
+ */
+const syncCommandsPlugin = {
+    name: "sync-commands",
+
+    setup(build) {
+        build.onStart(async () => {
+            const packageJsonPath = path.join(__dirname, "package.json");
+
+            const result = await esbuild.build({
+                entryPoints: [path.join(__dirname, "src/commands/index.ts")],
+                bundle: true,
+                write: false,
+                format: "cjs",
+                platform: "node",
+                logLevel: "silent",
+                plugins: [vscodeStubPlugin],
+            });
+
+            // any command file has `export default defineCommand`
+            const mod = { exports: {} };
+            const runModule = new Function("module", "exports", result.outputFiles[0].text);
+            runModule(mod, mod.exports);
+            const { commands } = mod.exports;
+
+            const currentJSON = fs.readFileSync(packageJsonPath, "utf8");
+            const package = JSON.parse(currentJSON);
+            package.contributes ??= {};
+            package.contributes.commands = commands
+                .map(({ id, title }) => ({
+                    command: `tatr-vsc.${id}`,
+                    title,
+                }));
+            const newJSON = `${JSON.stringify(package, null, 2)}\n`;
+
+            if (newJSON !== currentJSON) {
+                fs.writeFileSync(packageJsonPath, newJSON);
+                console.log("Updated package.json contributes.commands.");
+            }
+        });
+    },
+};
+
 /**
  * @type {import("esbuild").Plugin}
  */
@@ -38,6 +111,7 @@ async function main() {
         external: ["vscode"],
         logLevel: "silent",
         plugins: [
+            syncCommandsPlugin,
             esbuildProblemMatcherPlugin,
         ],
     });