[BUG] npx binary does not account for globally-installed packages

[billyjanitsch]

Current Behavior:

If a package foo that exposes a binary is installed globally, npm 7's npx foo does not work as expected. It asks whether to install foo rather than executing the already-installed binary.

This issue also occurs if the binary does not share the package name (e.g. if foo exposes binary bar, then npx bar doesn't work either).

Expected Behavior:

npx foo should invoke a globally-installed foo, as in npm@6. Or, if this change is intentional, could it be mentioned alongside the other breaking changes to npx in the npm@7 release notes?

Steps To Reproduce:

1. Run npm install -g npm-check-updates.
2. Run ncu. It successfully runs the npm-check-updates binary, as expected.
3. Run npx ncu. It does not run the binary. Instead, it asks whether it can install the ncu package:

Need to install the following packages:
  ncu
Ok to proceed? (y)

Environment:

• OS: macOS 10.15.6
• node: 14.9.0
• npm: 7.0.0-beta.7

[darcyclarke]

Assigning to @nlf as I believe this is related to #1845

[nlf]

@billyjanitsch this should be fixed in v7.0.0-rc.4, if you're able would you try updating to that version with npm i -g npm@next-7 and see if your issue is resolved?