[BUG] npx commands failing due to parsing bug

[Chriscbr]

Current Behavior:

$ npx node -e "console.log(3)"
sh: -c: line 0: syntax error near unexpected token `('
sh: -c: line 0: `node -e console.log(3)'
npm ERR! code 2
npm ERR! path /Users/rybickic/Developer/empty-dir
npm ERR! command failed
npm ERR! command sh -c node -e console.log(3)

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/rybickic/.npm/_logs/2020-12-24T08_25_37_431Z-debug.log

Expected Behavior:

$ npx node -e "console.log(3)"
3

Steps To Reproduce:

See commands above.

I've tried running this with several npm version combinations, and it appears to be a regression introduced in npm 7.1.0. That is, with the npm@7.0.15 the command succeeds (prints 3), but starting in npm@7.1.0 it fails. This was brought to my attention when I was updating to the latest node release (v15.5.0) two days ago via nvm, which updates npm to 7.3.0 (changelog).

Environment:

• OS: macOS Catalina 10.15.7
• Node: 15.5.0
• npm: 7.3.0

[ljharb]

Why would you need an npx prefix to run node?

[Chriscbr]

We were using it so that in a script, we could change the PATH environment variable to include the project's node_modules, and run commands from packages inside, e.g.:

PATH="$(npx node -e "console.log(process.env.PATH)")" some-command

My understanding is npx modifies the context a process runs in by automatically determining the right paths to add. If you omit the npx prefix, and ran node -e "console.log(process.env.PATH)" instead, the output value will not contain the project's node_modules, so some-command will fail (not be found).

We were using npx -c "echo $PATH" previously, but discovered this fails on Windows so we switched to the code above. For now, npx -c 'node -e "console.log(process.env.PATH)"' is another temporary solution we've found.

For the tool I am building, we don't want consumers to have to manually prefix commands with "npx" depending on whether it's an npm script or a python script etc. so that's why we are trying to set up the environment like this.

(This stackoverflow post is also in the same spirit of what I'm describing / the challenges - https://stackoverflow.com/questions/39990788/achieve-npm-run-x-behavior-without-a-scripts-entry)

[Chriscbr]

I tried this on 7.4.0 and the example I gave works now. 👍

[ljharb]

Fixed by #2448.