x test says eslint is missing but it isn't

[saethlin]

Summary

x test reports

fmt check
fmt info: No modified files detected for formatting.
tidy check
Checking tidy rustdoc_json...
`eslint` doesn't seem to be installed. Skipping tidy check for JS files.
You can install it using `npm install eslint@8.6.0`
`rustdoc-json-types` was not modified.
No error code explanation was removed!
x.py completions check

But I definitely have eslint installed:

╭ ➜ ben@archlinux:~/rust
╰ ➤ eslint -v
v9.31.0

The problem is that bootstrap is trying to detect the eslint version reported by npm list but I do not have NPM installed.

Bootstrap configuration (bootstrap.toml)

profile = "compiler"
change-id = 999999

[llvm]
assertions = true
download-ci-llvm = true
#targets = "X86"

[rust]
download-rustc = false
deny-warnings = false
new-symbol-mangling = false
codegen-units-std = 1
debug-assertions = false
debug-logging = false
debuginfo-level = "line-tables-only"
debuginfo-level-std = 2
incremental = false
frame-pointers = true
jemalloc = true

[build]
submodules = true
#sanitizers = true

Operating system

Linux archlinux 6.15.6-arch1-1

HEAD

9cd918bcbbc26deb005eb4e1bd9a445380195e56

[Kobzol]

As a general answer, bootstrap has to be able to use a specific version of eslint, otherwise it could show you lints that are different from CI. Even if bootstrap was able to detect your eslint version without npm (e.g. by calling something like eslint --version), it wouldn't be able to install a different version without npm. So suffice to say, npm is just required for this eslint check in tidy at the moment.

That being said, the fact that this warning is printed, and that tidy tries to even run eslint, is not ideal, and we are aiming to change that. After #142924 lands, tidy will no longer check any existing versions of eslint, it will just install it on its own using npm. But it will also only do that if you manually request JS to be linted.