Can't install rustup because of existing rust that I can't remove

[mikeyhew]

We have a copy of rustc version 1.14.0 installed on my school's server. I want to set up the latest version of rust (currently 1.15.1) in my home directory, ideally using rustup. But because of the existing copy of rust - which I can't remove, since I don't have root access - rustup-init fails with the following error:

warning: it looks like you have an existing installation of Rust
warning: rustup cannot be installed alongside Rust. Please uninstall first
warning: run `/usr/local/lib/rustlib/uninstall.sh` as root to uninstall Rust
error: cannot install while Rust is installed

[suhr]

I wonder why can't rustup have a special system toolchan, that cannot be installed or updated but can be chosen.

[brson]

I'm not sure the best way to fix this offhand. I think the reason I did this was to reduce potential confusion after install, having seen cases where people were still invoking the old rustc afterwards. For example, there are many cases where rustup fails to configure PATH, and that would leave the old rustc active.

We could possibly loosen this to a warning, like "warning: There is an existing rustc installed to $path. Depending on how $PATH is configured, the existing toolchain may take precedence."

Could also make it interactive, but that's deeper surgery.

A 'system' toolchain is a useful feature to add, but does not solve the problem of users being confused about which toolchain they are using.

[chris3k]

Temporary workaroud (let's call it - force install) for this, is to download rustup.rs source code and comment sanity checks in do_pre_install_sanity_checks() (or apply patch)

diff --git a/src/rustup-cli/self_update.rs b/src/rustup-cli/self_update.rs
index 7d1a641..c289962 100644
--- a/src/rustup-cli/self_update.rs
+++ b/src/rustup-cli/self_update.rs
@@ -381,7 +381,7 @@ fn do_pre_install_sanity_checks() -> Result<()> {
         warn!("it looks like you have an existing installation of Rust");
         warn!("rustup cannot be installed alongside Rust. Please uninstall first");
         warn!("run `{}` as root to uninstall Rust", uninstaller_path.display());
-        return Err("cannot install while Rust is installed".into());
+        // return Err("cannot install while Rust is installed".into());
     }

     if rustup_sh_exists {

Then compile (cargo build) and then proceed with installation, e.g. RUSTUP_HOME=/home/user/.multirust CARGO_HOME=/home/user/.cargo ./target/debug/rustup-init --no-modify-path.

[mikeyhew]

The copy of rustc that we had on my school's server has since been removed, so I was able to install rustup just fine when I tried it last week. That being said, there should be some way to force installation, even if there is an existing Rust installation somewhere.

[mgeisler]

You can bypass the check by setting RUSTUP_INIT_SKIP_PATH_CHECK to yes:

$ ./rustup-init 
error: it looks like you have an existing installation of Rust at:
error: /usr/bin
error: rustup cannot be installed alongside Rust. Please uninstall first
error: if this is what you want, restart the installation with `-y'
error: cannot install while Rust is installed
$ RUSTUP_INIT_SKIP_PATH_CHECK=yes ./rustup-init 

Welcome to Rust!

This will download and install the official compiler for the Rust programming 
language, and its package manager, Cargo.
# ...

I think the error message should at least mention this environment variable -- I only found it after looking through the source of rustup-init.

[yangchengjian]

I meet the some question too, and I use

$RUSTUP_INIT_SKIP_PATH_CHECK=yes sh ./rustup-init.sh 

to reinstall rust, It's work.

Thanks @mgeisler

[anjalianjali1234]

Sorry for the late reply.

You just need to run:
curl -sSf https://static.rust-lang.org/rustup.sh | sh

it will fix the problem.

[geofmureithi-zz]

@anjalianjali1234 This no longer works:(rustc1.3.0)

$ curl -sSf https://static.rust-lang.org/rustup.sh | sh
The location of rustup.sh has moved.
Run the following command to install from the new location:
    curl https://sh.rustup.rs -sSf | sh

[ssowellsvt]

Just run:

sudo apt remove rustc
then
curl https://sh.rustup.rs/ -sSf | sh

[mikeyhew]

@ssowellsvt one of the premises of this issue is that the user doesn't have root access and can't use sudo.

But as @mgeisler pointed out, RUSTUP_INIT_SKIP_PATH_CHECK=yes works. So I think we can close this issue?

[PAVAN-IS201401018]

The copy of rustc that we had on my school's server has since been removed, so I was able to install rustup just fine when I tried it last week. That being said, there should be some way to force installation, even if there is an existing Rust installation somewhere.

How it was removed?

[mikeyhew]

I don't know. Probably one of the admins removed it.