Undocumented environment variables?

[cher-nov]

Problem you are trying to solve

https://rust-lang.github.io/rustup/environment-variables.html
https://rust-lang.github.io/rustup/dev-guide/tips-and-tricks.html

After reading the rustup code a little (rust-lang/rust-forge#760), I found out that not all the environment variables it supports are documented. A quick search using grep -rniI -e "var(" -e "env\!(" -e "env(" -e "var_os(" revealed at least these:

rustup/src/cli/self_update/unix.rs

Line 21 in edf5c22

.var_os("RUSTUP_INIT_SKIP_SUDO_CHECK")

rustup/src/cli/self_update/windows.rs

Line 186 in edf5c22

if process.var("RUSTUP_INIT_SKIP_MSVC_CHECK").is_ok() {

rustup/src/cli/self_update.rs

Line 512 in edf5c22

.var_os("RUSTUP_INIT_SKIP_EXISTENCE_CHECKS")

rustup/src/cli/self_update.rs

Line 627 in edf5c22

let skip_check = process.var_os("RUSTUP_INIT_SKIP_PATH_CHECK");

rustup/src/dist/mod.rs

Line 368 in edf5c22

if let Some(triple) = option_env!("RUSTUP_OVERRIDE_BUILD_TRIPLE") {

rustup/src/dist/mod.rs

Line 534 in edf5c22

if let Ok(triple) = process.var("RUSTUP_OVERRIDE_HOST_TRIPLE") {

rustup/src/dist/mod.rs

Line 660 in edf5c22

let do_manifest_staging = process.var("RUSTUP_STAGED_MANIFEST").is_ok();

• Particularly important because current doc directly advises using RUSTUP_DIST_SERVER for this, contrary to f08c4fe:
  

  rustup/doc/user-guide/src/environment-variables.md

  Lines 17 to 20 in edf5c22

  	- `RUSTUP_DIST_SERVER` (default: `https://static.rust-lang.org`). Sets the root
  	URL for downloading static resources related to Rust. You can change this to
  	instead use a local mirror, or to test the binaries from the staging
  	directory.

rustup/src/utils/utils.rs

Line 248 in edf5c22

.var_os("RUSTUP_USE_RUSTLS")

rustup/src/config.rs

Line 274 in edf5c22

match process.var("RUSTUP_OVERRIDE_UNIX_FALLBACK_SETTINGS") {

rustup/src/config.rs

Line 400 in edf5c22

if self.process.var("CI").is_ok() && self.process.var("RUSTUP_CI").is_err() {

rustup/src/toolchain.rs

Line 247 in edf5c22

.var_os("RUSTUP_WINDOWS_PATH_ADD_BIN")

Solution you'd like

Describe all this somewhere and/or make a list of variables for internal use so as not to confuse people.

[djc]

You did not describe the "problem you are trying to solve". What is it? What are you confused about?

[cher-nov]

You did not describe the "problem you are trying to solve". What is it? What are you confused about?

Sorry, my English is far from perfect.
The thing that confuses me is the support for these variables in the code and their absence in the official documentation. That's it.

[djc]

Right -- the question I'm asking is, what are you trying to achieve that you need to understand these variables?

[cher-nov]

Right -- the question I'm asking is, what are you trying to achieve that you need to understand these variables?

How to correctly access the staging manifests at least. I just noticed that RUSTUP_STAGED_MANIFEST is not the only undocumented variable, and decided to make a list of them so that Rust developers don’t have to bother with this. "It is my duty to report." (c)

[djc]

I'm not sure it makes sense to me to document a list of internal-only environment variables. I think most of these should probably remain internal and keeping those undocumented seems okay to me.