[BUG] Install fails if "bin" script doesn't exist

[remcohaszing]

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

Current Behavior

This is a duplicate of #2632. This has been closed, but I still encounter it using the latest version of npm.

When running npm install in a project that references a bin script that doesn’t exist, the command fails with the error:

npm ERR! code ENOENT
npm ERR! syscall chmod
npm ERR! path /home/remco/Projects/appsemble/node_modules/@appsemble/server/dist/index.js
npm ERR! errno -2
npm ERR! enoent ENOENT: no such file or directory, chmod '/home/remco/Projects/appsemble/node_modules/@appsemble/server/dist/index.js'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent

Expected Behavior

npm install is succesful

Steps To Reproduce

git clone git@gitlab.com:appsemble/appsemble.git
cd appsemble
rm yarn.lock
npm install

Environment

• npm: 8.5.5
• Node.js: 16.14.2
• OS Name: Pop!_OS
• System Model Name:
• npm config:

; "global" config from /home/remco/.local/etc/npmrc

fund = false 

; node bin location = /usr/bin/node
; cwd = /home/remco/Projects/appsemble
; HOME = /home/remco
; Run `npm config ls -l` to show all defaults

[fritzy]

#2632 possible regression

[remcohaszing]

The issue still exists today in npm 9.

The issue occurs when two packages install the same executable name, but it doesn’t exist in the second package that is supposed to install that executable.

It’s simplest to reproduce with npm workspaces, but it applies to other dependencies as well.

Let’s say we have the following files:

package.json

{
  "workspaces": [
    "workspaces/*"
  ]
}

workspaces/a/package.json

{ 
  "name": "a",
  "bin": {
    "cli": "./cli.js"
  }
}

workspaces/b/package.json

{ 
  "name": "b",
  "bin": {
    "cli": "./cli.js"
  }
}

Running npm install from this project will reproduce the issue.

If we create an empty file workspaces/a/cli.js, the issue still exists. However, if we create an empty file workspaces/b/cli.js instead, the issue goes away.

[remcohaszing]

The problem is in https://github.com/npm/bin-links/blob/v4.0.1/lib/link-gently.js#L30-L33. This naively returns true if a link target was seen before. This indicates the file was linked succesfully. Then https://github.com/npm/bin-links/blob/main/lib/link-bin.js#L7 will try to make the non-existent file executable, which makes npm fail.