feat(cli/bunx): support --no-install flag

src/bun.zig

@@ -1613,6 +1613,7 @@ pub const renamer = @import("./renamer.zig");
 // TODO: Rename to SourceMap as this is a struct.
 pub const sourcemap = @import("./sourcemap/sourcemap.zig");
 
+/// Attempt to coerce some value into a byte slice.
 pub fn asByteSlice(buffer: anytype) []const u8 {
     return switch (@TypeOf(buffer)) {
         []const u8, []u8, [:0]const u8, [:0]u8 => buffer.ptr[0..buffer.len],

src/cli/bunx_command.zig

@@ -1,5 +1,7 @@
+const std = @import("std");
 const bun = @import("root").bun;
 const string = bun.string;
+const Allocator = std.mem.Allocator;
 const Output = bun.Output;
 const Global = bun.Global;
 const Environment = bun.Environment;
@@ -8,11 +10,11 @@ const MutableString = bun.MutableString;
 const stringZ = bun.stringZ;
 const default_allocator = bun.default_allocator;
 const C = bun.C;
-const std = @import("std");
 const cli = @import("../cli.zig");
+
 const Command = cli.Command;
 const Run = @import("./run_command.zig").RunCommand;
-const Allocator = std.mem.Allocator;
+const UpdateRequest = bun.PackageManager.UpdateRequest;
 
 const debug = Output.scoped(.bunx, false);
 
@@ -30,6 +32,9 @@ pub const BunxCommand = struct {
         // purposes.
         verbose_install: bool = false,
         silent_install: bool = false,
+        /// Skip installing the package, only running the target command if its
+        /// already downloaded. If its not, `bunx` exits with an error.
+        no_install: bool = false,
         allocator: Allocator,
 
         /// Create a new `Options` instance by parsing CLI arguments. `ctx` may be mutated.
@@ -65,6 +70,8 @@ pub const BunxCommand = struct {
                         opts.silent_install = true;
                     } else if (strings.eqlComptime(positional, "--bun") or strings.eqlComptime(positional, "-b")) {
                         ctx.debug.run_in_bun = true;
+                    } else if (strings.eqlComptime(positional, "--no-install")) {
+                        opts.no_install = true;
                     }
                 } else {
                     if (!found_subcommand_name) {
@@ -298,9 +305,9 @@ pub const BunxCommand = struct {
         var opts = try Options.parse(ctx, argv);
         defer opts.deinit();
 
-        var requests_buf = bun.PackageManager.UpdateRequest.Array.initCapacity(ctx.allocator, 64) catch bun.outOfMemory();
+        var requests_buf = UpdateRequest.Array.initCapacity(ctx.allocator, 64) catch bun.outOfMemory();
         defer requests_buf.deinit(ctx.allocator);
-        const update_requests = bun.PackageManager.UpdateRequest.parse(
+        const update_requests = UpdateRequest.parse(
             ctx.allocator,
             null,
             ctx.log,
@@ -335,6 +342,7 @@ pub const BunxCommand = struct {
 
         // fast path: they're actually using this interchangeably with `bun run`
         // so we use Bun.which to check
+        // SAFETY: initialized by Run.configureEnvForRun
         var this_transpiler: bun.Transpiler = undefined;
         var ORIGINAL_PATH: string = "";
 
@@ -384,7 +392,7 @@ pub const BunxCommand = struct {
                 else => ":",
             };
 
-            const has_banned_char = bun.strings.indexAnyComptime(update_request.name, banned_path_chars) != null or bun.strings.indexAnyComptime(display_version, banned_path_chars) != null;
+            const has_banned_char = strings.indexAnyComptime(update_request.name, banned_path_chars) != null or strings.indexAnyComptime(display_version, banned_path_chars) != null;
 
             break :brk try if (has_banned_char)
                 // This branch gets hit usually when a URL is requested as the package
@@ -503,8 +511,10 @@ pub const BunxCommand = struct {
         const passthrough = opts.passthrough_list.items;
 
         var do_cache_bust = update_request.version.tag == .dist_tag;
+        const look_for_existing_bin = update_request.version.literal.isEmpty() or update_request.version.tag != .dist_tag;
 
-        if (update_request.version.literal.isEmpty() or update_request.version.tag != .dist_tag) try_run_existing: {
+        debug("try run existing? {}", .{look_for_existing_bin});
+        if (look_for_existing_bin) try_run_existing: {
             var destination_: ?[:0]const u8 = null;
 
             // Only use the system-installed version if there is no version specified
@@ -563,11 +573,17 @@ pub const BunxCommand = struct {
                     };
 
                     if (is_stale) {
+                        debug("found stale binary: {s}", .{out});
                         do_cache_bust = true;
-                        break :try_run_existing;
+                        if (opts.no_install) {
+                            Output.warn("Using a stale installation of <b>{s}<r> because --no-install was passed. Run `bunx` without --no-install to use a fresh binary.", .{update_request.name});
+                        } else {
+                            break :try_run_existing;
+                        }
                     }
                 }
 
+                debug("running existing binary: {s}", .{destination});
                 try Run.runBinary(
                     ctx,
                     try this_transpiler.fs.dirname_store.append(@TypeOf(out), out),
@@ -626,6 +642,24 @@ pub const BunxCommand = struct {
                 }
             }
         }
+        // If we've reached this point, it means we couldn't find an existing binary to run.
+        // Next step is to install, then run it.
+
+        // NOTE: npx prints errors like this:
+        //
+        //     npm error npx canceled due to missing packages and no YES option: ["[email protected]"]
+        //     npm error A complete log of this run can be found in: [folder]/debug.log
+        //
+        // Which is not very helpful.
+
+        if (opts.no_install) {
+            Output.errGeneric(
+                "Could not find an existing '{s}' binary to run. Stopping because --no-install was passed.",
+                .{initial_bin_name},
+            );
+            Global.exit(1);
+        }
+
         const bunx_install_dir = try std.fs.cwd().makeOpenPath(bunx_cache_dir, .{});
 
         create_package_json: {

test/cli/install/bunx.test.ts

@@ -1,5 +1,5 @@
 import { spawn } from "bun";
-import { beforeAll, beforeEach, expect, it, setDefaultTimeout } from "bun:test";
+import { describe, beforeAll, beforeEach, expect, it, setDefaultTimeout } from "bun:test";
 import { rm, writeFile } from "fs/promises";
 import { bunEnv, bunExe, isWindows, tmpdirSync, readdirSorted } from "harness";
 import { readdirSync } from "node:fs";
@@ -83,7 +83,7 @@ it("should choose the tagged versions instead of the PATH versions when a tag is
       cwd: x_dir,
       stdout: "pipe",
       stdin: "ignore",
-      stderr: "inherit",
+      stderr: "ignore",
       env: {
         ...env,
         // BUN_DEBUG_QUIET_LOGS: undefined,
@@ -280,7 +280,7 @@ it("should work for github repository with committish", async () => {
 
   // cached
   const cached = spawn({
-    cmd: [bunExe(), "x", "github:piuccio/cowsay#HEAD", "hello bun!"],
+    cmd: [bunExe(), "x", "--no-install", "github:piuccio/cowsay#HEAD", "hello bun!"],
     cwd: x_dir,
     stdout: "pipe",
     stdin: "inherit",
@@ -396,3 +396,77 @@ it('should set "npm_config_user_agent" to bun', async () => {
   expect(out.trim()).toContain(`bun/${Bun.version}`);
   expect(exited).toBe(0);
 });
+
+/**
+ * IMPORTANT
+ * Please only use packages with small unpacked sizes for tests. It helps keep them fast.
+ */
+describe("bunx --no-install", () => {
+  const run = (...args: string[]): Promise<[stderr: string, stdout: string, exitCode: number]> => {
+    const subprocess = spawn({
+      cmd: [bunExe(), "x", ...args],
+      cwd: x_dir,
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+
+    return Promise.all([
+      new Response(subprocess.stderr).text(),
+      new Response(subprocess.stdout).text(),
+      subprocess.exited,
+    ] as const);
+  };
+
+  it("if the package is not installed, it should fail and print an error message", async () => {
+    const [err, out, exited] = await run("--no-install", "http-server", "--version");
+
+    expect(err.trim()).toContain(
+      "Could not find an existing 'http-server' binary to run.",
+    );
+    expect(out).toHaveLength(0);
+    expect(exited).toBe(1);
+  });
+
+  /*
+    yes, multiple package tests are neccessary.
+      1. there's specialized logic for `bunx tsc` and `bunx typescript`
+      2. http-server checks for non-alphanumeric edge cases. Plus it's small
+      3. eslint is alphanumeric and extremely common
+   */
+  it.each(["typescript", "http-server", "eslint"])("`bunx --no-install %s` should find cached packages", async pkg => {
+    // not cached
+    {
+      const [err, out, code] = await run(pkg, "--version");
+      expect(err).not.toContain("error:");
+      expect(out).not.toBeEmpty();
+      expect(code).toBe(0);
+    }
+
+    // cached
+    {
+      const [err, out, code] = await run("--no-install", pkg, "--version");
+      expect(err).not.toContain("error:");
+      expect(out).not.toBeEmpty();
+      expect(code).toBe(0);
+    }
+  });
+
+  it("when an exact version match is found, should find cached packages", async () => {
+    // not cached
+    {
+      const [err, out, code] = await run("[email protected]", "--version");
+      expect(err).not.toContain("error:");
+      expect(out).not.toBeEmpty();
+      expect(code).toBe(0);
+    }
+
+    // cached
+    {
+      const [err, out, code] = await run("--no-install", "[email protected]", "--version");
+      expect(err).not.toContain("error:");
+      expect(out).not.toBeEmpty();
+      expect(code).toBe(0);
+    }
+  });
+});