feat(toolchain): add automatic bundled Rust toolchain fallback and integrate with CLI/CargoRunner

ts/mod_cli/classes.tsrustcli.ts

@@ -3,6 +3,7 @@ import * as plugins from '../plugins.js';
 import { CargoConfig } from '../mod_cargo/index.js';
 import { CargoRunner } from '../mod_cargo/index.js';
 import { FsHelpers } from '../mod_fs/index.js';
+import { ToolchainManager } from '../mod_toolchain/index.js';
 
 /** Maps friendly target names to Rust target triples */
 const targetAliasMap: Record<string, string> = {
@@ -62,18 +63,33 @@ export class TsRustCli {
     this.registerCleanCommand();
   }
 
+  /**
+   * Resolves the Rust toolchain to use. Tries system cargo first,
+   * then falls back to a bundled toolchain at /tmp/tsrust_toolchain/.
+   * Returns the envPrefix string to prepend to shell commands.
+   */
+  private async resolveToolchain(): Promise<string> {
+    // 1. Try system cargo
+    const systemRunner = new CargoRunner(this.cwd);
+    if (await systemRunner.checkCargoInstalled()) {
+      return ''; // system toolchain, no prefix needed
+    }
+
+    // 2. Fall back to bundled toolchain
+    console.log('System cargo not found. Checking for bundled toolchain...');
+    const toolchain = new ToolchainManager();
+    await toolchain.ensureInstalled();
+    return toolchain.getEnvPrefix();
+  }
+
   private registerStandardCommand(): void {
     this.cli.standardCommand().subscribe(async (argvArg) => {
       const startTime = Date.now();
 
-      // Check cargo is installed
-      const runner = new CargoRunner(this.cwd); // temporary, just for version check
-      if (!(await runner.checkCargoInstalled())) {
-        console.error('Error: cargo is not installed or not in PATH.');
-        console.error('Install Rust via https://rustup.rs/');
-        process.exit(1);
-      }
+      // Resolve toolchain (system or bundled fallback)
+      const envPrefix = await this.resolveToolchain();
 
+      const runner = new CargoRunner(this.cwd, envPrefix);
       const cargoVersion = await runner.getCargoVersion();
       console.log(`Using ${cargoVersion}`);
 
@@ -125,7 +141,7 @@ export class TsRustCli {
 
         for (const { triple, friendly } of resolvedTargets) {
           console.log(`\n--- Building for ${friendly} (${triple}) ---`);
-          const cargoRunner = new CargoRunner(rustDir);
+          const cargoRunner = new CargoRunner(rustDir, envPrefix);
           const buildResult = await cargoRunner.build({ debug: isDebug, clean: shouldClean, target: triple });
 
           if (!buildResult.success) {
@@ -159,8 +175,8 @@ export class TsRustCli {
           }
         }
       } else {
-        // Native build (unchanged behavior)
-        const cargoRunner = new CargoRunner(rustDir);
+        // Native build
+        const cargoRunner = new CargoRunner(rustDir, envPrefix);
         const buildResult = await cargoRunner.build({ debug: isDebug, clean: shouldClean });
 
         if (!buildResult.success) {
@@ -199,8 +215,9 @@ export class TsRustCli {
       // Clean cargo build
       const rustDir = await this.detectRustDir();
       if (rustDir) {
+        const envPrefix = await this.resolveToolchain();
         console.log('Running cargo clean...');
-        const runner = new CargoRunner(rustDir);
+        const runner = new CargoRunner(rustDir, envPrefix);
         await runner.clean();
         console.log('Cargo clean complete.');
       }