fix!(config): re-enable active toolchain installation in Cfg::find_active_toolchain() with optional opt-out

src/cli/common.rs

@@ -406,7 +406,7 @@ pub(super) fn list_items(
     Ok(utils::ExitCode(0))
 }
 
-pub(crate) fn list_toolchains(
+pub(crate) async fn list_toolchains(
     cfg: &Cfg<'_>,
     verbose: bool,
     quiet: bool,
@@ -418,7 +418,7 @@ pub(crate) fn list_toolchains(
         let default_toolchain_name = cfg.get_default()?;
         let active_toolchain_name: Option<ToolchainName> =
             if let Ok(Some((LocalToolchainName::Named(toolchain), _reason))) =
-                cfg.find_active_toolchain()
+                cfg.find_active_toolchain(None).await
             {
                 Some(toolchain)
             } else {

src/cli/proxy_mode.rs

@@ -32,6 +32,9 @@ pub async fn main(arg0: &str, current_dir: PathBuf, process: &Process) -> Result
         .collect();
 
     let cfg = set_globals(current_dir, true, process)?;
-    let cmd = cfg.resolve_local_toolchain(toolchain)?.command(arg0)?;
+    let cmd = cfg
+        .resolve_local_toolchain(toolchain)
+        .await?
+        .command(arg0)?;
     run_command_for_dir(cmd, arg0, &cmd_args)
 }

src/cli/rustup_mode.rs

@@ -560,7 +560,7 @@ pub async fn main(
             write!(process.stdout().lock(), "{err}")?;
             info!("This is the version for the rustup toolchain manager, not the rustc compiler.");
             let mut cfg = common::set_globals(current_dir, true, process)?;
-            match cfg.active_rustc_version() {
+            match cfg.active_rustc_version().await {
                 Ok(Some(version)) => info!("The currently active `rustc` version is `{version}`"),
                 Ok(None) => info!("No `rustc` is currently active"),
                 Err(err) => trace!("Failed to display the current `rustc` version: {err}"),
@@ -601,10 +601,12 @@ pub async fn main(
     match subcmd {
         RustupSubcmd::DumpTestament => common::dump_testament(process),
         RustupSubcmd::Install { opts } => update(cfg, opts, true).await,
-        RustupSubcmd::Uninstall { opts } => toolchain_remove(cfg, opts),
+        RustupSubcmd::Uninstall { opts } => toolchain_remove(cfg, opts).await,
         RustupSubcmd::Show { verbose, subcmd } => handle_epipe(match subcmd {
-            None => show(cfg, verbose),
-            Some(ShowSubcmd::ActiveToolchain { verbose }) => show_active_toolchain(cfg, verbose),
+            None => show(cfg, verbose).await,
+            Some(ShowSubcmd::ActiveToolchain { verbose }) => {
+                show_active_toolchain(cfg, verbose).await
+            }
             Some(ShowSubcmd::Home) => show_rustup_home(cfg),
             Some(ShowSubcmd::Profile) => {
                 writeln!(process.stdout().lock(), "{}", cfg.get_profile()?)?;
@@ -633,12 +635,12 @@ pub async fn main(
         RustupSubcmd::Toolchain { subcmd } => match subcmd {
             ToolchainSubcmd::Install { opts } => update(cfg, opts, true).await,
             ToolchainSubcmd::List { verbose, quiet } => {
-                handle_epipe(common::list_toolchains(cfg, verbose, quiet))
+                handle_epipe(common::list_toolchains(cfg, verbose, quiet).await)
             }
             ToolchainSubcmd::Link { toolchain, path } => {
                 toolchain_link(cfg, &toolchain, &path).await
             }
-            ToolchainSubcmd::Uninstall { opts } => toolchain_remove(cfg, opts),
+            ToolchainSubcmd::Uninstall { opts } => toolchain_remove(cfg, opts).await,
         },
         RustupSubcmd::Check => check_updates(cfg).await,
         RustupSubcmd::Default {
@@ -751,7 +753,7 @@ async fn default_(
             }
         };
 
-        if let Some((toolchain, reason)) = cfg.find_active_toolchain()? {
+        if let Some((toolchain, reason)) = cfg.find_active_toolchain(None).await? {
             if !matches!(reason, ActiveReason::Default) {
                 info!("note that the toolchain '{toolchain}' is currently in use ({reason})");
             }
@@ -928,7 +930,7 @@ async fn which(
     binary: &str,
     toolchain: Option<ResolvableToolchainName>,
 ) -> Result<utils::ExitCode> {
-    let binary_path = cfg.resolve_toolchain(toolchain)?.binary_file(binary);
+    let binary_path = cfg.resolve_toolchain(toolchain).await?.binary_file(binary);
 
     utils::assert_is_file(&binary_path)?;
 
@@ -937,7 +939,7 @@ async fn which(
 }
 
 #[tracing::instrument(level = "trace", skip_all)]
-fn show(cfg: &Cfg<'_>, verbose: bool) -> Result<utils::ExitCode> {
+async fn show(cfg: &Cfg<'_>, verbose: bool) -> Result<utils::ExitCode> {
     common::warn_if_host_is_emulated(cfg.process);
 
     // Print host triple
@@ -962,7 +964,7 @@ fn show(cfg: &Cfg<'_>, verbose: bool) -> Result<utils::ExitCode> {
     let installed_toolchains = cfg.list_toolchains()?;
     let active_toolchain_and_reason: Option<(ToolchainName, ActiveReason)> =
         if let Ok(Some((LocalToolchainName::Named(toolchain_name), reason))) =
-            cfg.find_active_toolchain()
+            cfg.find_active_toolchain(None).await
         {
             Some((toolchain_name, reason))
         } else {
@@ -1081,8 +1083,8 @@ fn show(cfg: &Cfg<'_>, verbose: bool) -> Result<utils::ExitCode> {
 }
 
 #[tracing::instrument(level = "trace", skip_all)]
-fn show_active_toolchain(cfg: &Cfg<'_>, verbose: bool) -> Result<utils::ExitCode> {
-    match cfg.find_active_toolchain()? {
+async fn show_active_toolchain(cfg: &Cfg<'_>, verbose: bool) -> Result<utils::ExitCode> {
+    match cfg.find_active_toolchain(None).await? {
         Some((toolchain_name, reason)) => {
             let toolchain = Toolchain::with_reason(cfg, toolchain_name.clone(), &reason)?;
             writeln!(
@@ -1118,7 +1120,7 @@ async fn target_list(
     quiet: bool,
 ) -> Result<utils::ExitCode> {
     // downcasting required because the toolchain files can name any toolchain
-    let distributable = DistributableToolchain::from_partial(toolchain, cfg)?;
+    let distributable = DistributableToolchain::from_partial(toolchain, cfg).await?;
     common::list_items(
         distributable,
         |c| {
@@ -1145,7 +1147,7 @@ async fn target_add(
     // isn't a feature yet.
     // list_components *and* add_component would both be inappropriate for
     // custom toolchains.
-    let distributable = DistributableToolchain::from_partial(toolchain, cfg)?;
+    let distributable = DistributableToolchain::from_partial(toolchain, cfg).await?;
     let components = distributable.components()?;
 
     if targets.contains(&"all".to_string()) {
@@ -1189,7 +1191,7 @@ async fn target_remove(
     targets: Vec<String>,
     toolchain: Option<PartialToolchainDesc>,
 ) -> Result<utils::ExitCode> {
-    let distributable = DistributableToolchain::from_partial(toolchain, cfg)?;
+    let distributable = DistributableToolchain::from_partial(toolchain, cfg).await?;
 
     for target in targets {
         let target = TargetTriple::new(target);
@@ -1227,7 +1229,7 @@ async fn component_list(
     quiet: bool,
 ) -> Result<utils::ExitCode> {
     // downcasting required because the toolchain files can name any toolchain
-    let distributable = DistributableToolchain::from_partial(toolchain, cfg)?;
+    let distributable = DistributableToolchain::from_partial(toolchain, cfg).await?;
     common::list_items(
         distributable,
         |c| Some(&c.name),
@@ -1243,7 +1245,7 @@ async fn component_add(
     toolchain: Option<PartialToolchainDesc>,
     target: Option<String>,
 ) -> Result<utils::ExitCode> {
-    let distributable = DistributableToolchain::from_partial(toolchain, cfg)?;
+    let distributable = DistributableToolchain::from_partial(toolchain, cfg).await?;
     let target = get_target(target, &distributable);
 
     for component in &components {
@@ -1269,7 +1271,7 @@ async fn component_remove(
     toolchain: Option<PartialToolchainDesc>,
     target: Option<String>,
 ) -> Result<utils::ExitCode> {
-    let distributable = DistributableToolchain::from_partial(toolchain, cfg)?;
+    let distributable = DistributableToolchain::from_partial(toolchain, cfg).await?;
     let target = get_target(target, &distributable);
 
     for component in &components {
@@ -1311,9 +1313,14 @@ async fn toolchain_link(
     Ok(utils::ExitCode(0))
 }
 
-fn toolchain_remove(cfg: &mut Cfg<'_>, opts: UninstallOpts) -> Result<utils::ExitCode> {
+async fn toolchain_remove(cfg: &mut Cfg<'_>, opts: UninstallOpts) -> Result<utils::ExitCode> {
     let default_toolchain = cfg.get_default().ok().flatten();
-    let active_toolchain = cfg.find_active_toolchain().ok().flatten().map(|(it, _)| it);
+    let active_toolchain = cfg
+        .find_active_toolchain(Some(false))
+        .await
+        .ok()
+        .flatten()
+        .map(|(it, _)| it);
 
     for toolchain_name in &opts.toolchain {
         let toolchain_name = toolchain_name.resolve(&cfg.get_default_host_triple()?)?;
@@ -1556,7 +1563,7 @@ async fn doc(
     mut topic: Option<&str>,
     doc_page: &DocPage,
 ) -> Result<utils::ExitCode> {
-    let toolchain = cfg.toolchain_from_partial(toolchain)?;
+    let toolchain = cfg.toolchain_from_partial(toolchain).await?;
 
     if let Ok(distributable) = DistributableToolchain::try_from(&toolchain) {
         if let [_] = distributable
@@ -1625,7 +1632,7 @@ async fn man(
     command: &str,
     toolchain: Option<PartialToolchainDesc>,
 ) -> Result<utils::ExitCode> {
-    let toolchain = cfg.toolchain_from_partial(toolchain)?;
+    let toolchain = cfg.toolchain_from_partial(toolchain).await?;
     let path = toolchain.man_path();
     utils::assert_is_directory(&path)?;
 

src/config.rs

@@ -500,7 +500,7 @@ impl<'a> Cfg<'a> {
             .transpose()?)
     }
 
-    pub(crate) fn toolchain_from_partial(
+    pub(crate) async fn toolchain_from_partial(
         &self,
         toolchain: Option<PartialToolchainDesc>,
     ) -> anyhow::Result<Toolchain<'_>> {
@@ -511,20 +511,68 @@ impl<'a> Cfg<'a> {
                 )))
             })
             .transpose()?;
-        self.local_toolchain(toolchain)
+        self.local_toolchain(toolchain).await
     }
 
-    pub(crate) fn find_active_toolchain(
+    pub(crate) async fn find_active_toolchain(
         &self,
+        force_install_active: Option<bool>,
     ) -> Result<Option<(LocalToolchainName, ActiveReason)>> {
-        Ok(
-            if let Some((override_config, reason)) = self.find_override_config()? {
-                Some((override_config.into_local_toolchain_name(), reason))
-            } else {
-                self.get_default()?
-                    .map(|x| (x.into(), ActiveReason::Default))
-            },
-        )
+        let (components, targets, profile, toolchain, reason) = match self.find_override_config()? {
+            Some((
+                OverrideCfg::Official {
+                    components,
+                    targets,
+                    profile,
+                    toolchain,
+                },
+                reason,
+            )) => (components, targets, profile, toolchain, reason),
+            Some((override_config, reason)) => {
+                return Ok(Some((override_config.into_local_toolchain_name(), reason)));
+            }
+            None => {
+                return Ok(self
+                    .get_default()?
+                    .map(|x| (x.into(), ActiveReason::Default)));
+            }
+        };
+
+        let should_install_active = force_install_active.unwrap_or_else(|| {
+            self.process
+                .var("RUSTUP_AUTO_INSTALL")
+                .map_or(true, |it| it != "0")
+        });
+
+        if !should_install_active {
+            return Ok(Some(((&toolchain).into(), reason)));
+        }
+
+        let components = components.iter().map(AsRef::as_ref).collect::<Vec<_>>();
+        let targets = targets.iter().map(AsRef::as_ref).collect::<Vec<_>>();
+        match DistributableToolchain::new(self, toolchain.clone()) {
+            Err(RustupError::ToolchainNotInstalled { .. }) => {
+                DistributableToolchain::install(
+                    self,
+                    &toolchain,
+                    &components,
+                    &targets,
+                    profile.unwrap_or_default(),
+                    false,
+                )
+                .await?;
+            }
+            Ok(mut distributable) => {
+                if !distributable.components_exist(&components, &targets)? {
+                    distributable
+                        .update(&components, &targets, profile.unwrap_or_default())
+                        .await?;
+                }
+            }
+            Err(e) => return Err(e.into()),
+        };
+
+        Ok(Some(((&toolchain).into(), reason)))
     }
 
     fn find_override_config(&self) -> Result<Option<(OverrideCfg, ActiveReason)>> {
@@ -703,43 +751,44 @@ impl<'a> Cfg<'a> {
     }
 
     #[tracing::instrument(level = "trace")]
-    pub(crate) fn active_rustc_version(&mut self) -> Result<Option<String>> {
+    pub(crate) async fn active_rustc_version(&mut self) -> Result<Option<String>> {
         if let Some(t) = self.process.args().find(|x| x.starts_with('+')) {
             trace!("Fetching rustc version from toolchain `{}`", t);
             self.set_toolchain_override(&ResolvableToolchainName::try_from(&t[1..])?);
         }
 
-        let Some((name, _)) = self.find_active_toolchain()? else {
+        let Some((name, _)) = self.find_active_toolchain(None).await? else {
             return Ok(None);
         };
         Ok(Some(Toolchain::new(self, name)?.rustc_version()))
     }
 
-    pub(crate) fn resolve_toolchain(
+    pub(crate) async fn resolve_toolchain(
         &self,
         name: Option<ResolvableToolchainName>,
     ) -> Result<Toolchain<'_>> {
         let toolchain = name
             .map(|name| anyhow::Ok(name.resolve(&self.get_default_host_triple()?)?.into()))
             .transpose()?;
-        self.local_toolchain(toolchain)
+        self.local_toolchain(toolchain).await
     }
 
-    pub(crate) fn resolve_local_toolchain(
+    pub(crate) async fn resolve_local_toolchain(
         &self,
         name: Option<ResolvableLocalToolchainName>,
     ) -> Result<Toolchain<'_>> {
         let local = name
             .map(|name| name.resolve(&self.get_default_host_triple()?))
             .transpose()?;
-        self.local_toolchain(local)
+        self.local_toolchain(local).await
     }
 
-    fn local_toolchain(&self, name: Option<LocalToolchainName>) -> Result<Toolchain<'_>> {
+    async fn local_toolchain(&self, name: Option<LocalToolchainName>) -> Result<Toolchain<'_>> {
         let toolchain = match name {
             Some(tc) => tc,
             None => {
-                self.find_active_toolchain()?
+                self.find_active_toolchain(None)
+                    .await?
                     .ok_or_else(|| no_toolchain_error(self.process))?
                     .0
             }

src/toolchain/distributable.rs

@@ -32,11 +32,13 @@ pub(crate) struct DistributableToolchain<'a> {
 }
 
 impl<'a> DistributableToolchain<'a> {
-    pub(crate) fn from_partial(
+    pub(crate) async fn from_partial(
         toolchain: Option<PartialToolchainDesc>,
         cfg: &'a Cfg<'a>,
     ) -> anyhow::Result<Self> {
-        Ok(Self::try_from(&cfg.toolchain_from_partial(toolchain)?)?)
+        Ok(Self::try_from(
+            &cfg.toolchain_from_partial(toolchain).await?,
+        )?)
     }
 
     pub(crate) fn new(cfg: &'a Cfg<'a>, desc: ToolchainDesc) -> Result<Self, RustupError> {