Support `bun run --if-present` (#6248)

* Support --if-present
Closes #5670

* More robust tests, handle more cases

4 files changed, 131 insertions, 1 deletions

diff --git a/src/cli.zig b/src/cli.zig
index 9982e5e7f..a05fb3768 100644
--- a/src/cli.zig
+++ b/src/cli.zig
@@ -196,6 +196,7 @@ pub const Arguments = struct {
         clap.parseParam("--inspect <STR>?                  Activate Bun's Debugger") catch unreachable,
         clap.parseParam("--inspect-wait <STR>?             Activate Bun's Debugger, wait for a connection before executing") catch unreachable,
         clap.parseParam("--inspect-brk <STR>?              Activate Bun's Debugger, set breakpoint on first line of code and wait") catch unreachable,
+        clap.parseParam("--if-present                      Exit if the entrypoint does not exist") catch unreachable,
         clap.parseParam("<POS>...                          ") catch unreachable,
     };
 
@@ -538,6 +539,7 @@ pub const Arguments = struct {
                 ctx.preloads = preloads;
             }
 
+            ctx.runtime_options.if_present = args.flag("--if-present");
             ctx.runtime_options.smol = args.flag("--smol");
             if (args.option("--inspect")) |inspect_flag| {
                 ctx.runtime_options.debugger = if (inspect_flag.len == 0)
@@ -1022,6 +1024,7 @@ pub const Command = struct {
     pub const RuntimeOptions = struct {
         smol: bool = false,
         debugger: Debugger = .{ .unspecified = {} },
+        if_present: bool = false,
     };
 
     pub const Context = struct {
@@ -1666,6 +1669,10 @@ pub const Command = struct {
                     Global.exit(1);
                 }
 
+                if (ctx.runtime_options.if_present) {
+                    return;
+                }
+
                 if (was_js_like) {
                     Output.prettyErrorln("<r><red>error<r><d>:<r> module not found \"<b>{s}<r>\"", .{
                         ctx.positionals[0],
diff --git a/src/cli/run_command.zig b/src/cli/run_command.zig
index 1ef1342c0..19046e292 100644
--- a/src/cli/run_command.zig
+++ b/src/cli/run_command.zig
@@ -1160,6 +1160,10 @@ pub const RunCommand = struct {
             }
         }
 
+        if (ctx.runtime_options.if_present) {
+            return true;
+        }
+
         if (comptime log_errors) {
             Output.prettyError("<r><red>error<r><d>:<r> missing script \"<b>{s}<r>\"\n", .{script_name_to_search});
             Global.exit(1);
diff --git a/test/cli/run/if-present.test.ts b/test/cli/run/if-present.test.ts
new file mode 100644
index 000000000..120970b46
--- /dev/null
+++ b/test/cli/run/if-present.test.ts
@@ -0,0 +1,119 @@
+import { describe, test, expect, beforeAll } from "bun:test";
+import { spawnSync } from "bun";
+import { bunEnv, bunExe, tempDirWithFiles } from "harness";
+
+let cwd: string;
+
+beforeAll(() => {
+  cwd = tempDirWithFiles("--if-present", {
+    "present.js": "console.log('Here!');",
+    "package.json": JSON.stringify({
+      "name": "present",
+      "scripts": {
+        "present": "echo 'Here!'",
+      },
+    }),
+  });
+});
+
+describe("bun", () => {
+  test("should error with missing script", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "notpresent"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toBeEmpty();
+    expect(stderr.toString()).toMatch(/script not found/);
+    expect(exitCode).toBe(1);
+  });
+  test("should error with missing module", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "./notpresent.js"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toBeEmpty();
+    expect(stderr.toString()).toMatch(/module not found/);
+    expect(exitCode).toBe(1);
+  });
+  test("should error with missing file", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "/path/to/notpresent.txt"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toBeEmpty();
+    expect(stderr.toString()).toMatch(/file not found/);
+    expect(exitCode).toBe(1);
+  });
+});
+
+describe("bun --if-present", () => {
+  test("should not error with missing script", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "--if-present", "notpresent"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toBeEmpty();
+    expect(stderr.toString()).toBeEmpty();
+    expect(exitCode).toBe(0);
+  });
+  test("should not error with missing module", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "--if-present", "./notpresent.js"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toBeEmpty();
+    expect(stderr.toString()).toBeEmpty();
+    expect(exitCode).toBe(0);
+  });
+  test("should not error with missing file", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "--if-present", "/path/to/notpresent.txt"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toBeEmpty();
+    expect(stderr.toString()).toBeEmpty();
+    expect(exitCode).toBe(0);
+  });
+  test("should run present script", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "run", "present"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toMatch(/Here!/);
+    expect(stderr.toString()).not.toBeEmpty();
+    expect(exitCode).toBe(0);
+  });
+  test("should run present module", () => {
+    const { exitCode, stdout, stderr } = spawnSync({
+      cwd,
+      cmd: [bunExe(), "run", "present.js"],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    expect(stdout.toString()).toMatch(/Here!/);
+    expect(stderr.toString()).toBeEmpty();
+    expect(exitCode).toBe(0);
+  });
+});
diff --git a/test/harness.ts b/test/harness.ts
index 16d04c1b4..77b4b4f43 100644
--- a/test/harness.ts
+++ b/test/harness.ts
@@ -84,7 +84,7 @@ export function hideFromStackTrace(block: CallableFunction) {
   });
 }
 
-export function tempDirWithFiles(basename: string, files: Record<string, string | Record<string, string>>) {
+export function tempDirWithFiles(basename: string, files: Record<string, string | Record<string, string>>): string {
   var fs = require("fs");
   var path = require("path");
   var { tmpdir } = require("os");