Revert "freeze used rustup version to 1.27.1, don't self-update rustup"

This reverts commit 9941bc8.

Author: ChrisDenton

src/toolchain.rs

@@ -49,7 +49,6 @@ impl DistToolchain {
                 self.name(),
                 "--profile",
                 workspace.rustup_profile(),
-                "--no-self-update",
             ])
             .run()
             .with_context(|| format!("unable to install toolchain {} via rustup", self.name()))?;

src/tools/rustup.rs

@@ -8,10 +8,7 @@ use std::fs::{self, File};
 use std::io;
 use tempfile::tempdir;
 
-// we're using an old version of rustup, since rustup 1.28 is broken for rustwide for now.
-// We'll try to either fix rustup, or adapt rustwide to fix this, until then, we'll use this version.
-// see https://github.com/rust-lang/rustup/issues/4224
-static RUSTUP_VERSION: &str = "1.27.1";
+static RUSTUP_BASE_URL: &str = "https://static.rust-lang.org/rustup/dist";
 
 pub(crate) struct Rustup;
 
@@ -40,10 +37,10 @@ impl Tool for Rustup {
         fs::create_dir_all(workspace.rustup_home())?;
 
         let url = format!(
-            "https://static.rust-lang.org/rustup/archive/{version}/{target}/rustup-init{exe_suffix}",
-            version = RUSTUP_VERSION,
-            target = crate::HOST_TARGET,
-            exe_suffix = EXE_SUFFIX
+            "{}/{}/rustup-init{}",
+            RUSTUP_BASE_URL,
+            crate::HOST_TARGET,
+            EXE_SUFFIX
         );
         let mut resp = workspace
             .http_client()
@@ -78,7 +75,11 @@ impl Tool for Rustup {
 
     fn update(&self, workspace: &Workspace, _fast_install: bool) -> anyhow::Result<()> {
         Command::new(workspace, &RUSTUP)
-            .args(&["update", MAIN_TOOLCHAIN_NAME, "--no-self-update"])
+            .args(&["self", "update"])
+            .run()
+            .context("failed to update rustup")?;
+        Command::new(workspace, &RUSTUP)
+            .args(&["update", MAIN_TOOLCHAIN_NAME])
             .run()
             .with_context(|| format!("failed to update main toolchain {}", MAIN_TOOLCHAIN_NAME))?;
         Ok(())