Support self-update modes

test: clean up "--no-self-update" args
test: add check-only and enable tests
docs: update docs and add comment

Author: 0xPoe

doc/src/basics.md

@@ -30,20 +30,33 @@ info: downloading self-updates
 
 ## Keeping `rustup` up to date
 
-Running `rustup update` also checks for updates to `rustup` itself and automatically
-installs the latest version. To manually update `rustup` only,
-without updating installed toolchains, type `rustup self update`:
+If your `rustup` was built with the `no-self-update` feature, it can not update
+itself. This is not the default, and only versions of `rustup` built with
+`--no-default-features`, or obtained from a third-party distributor who has
+disabled it (such as the Ubuntu snap store).
+
+Otherwise Rustup can update itself. It is possible to control Rustup's automatic
+self update mechanism with the `auto-self-update` configuration variable. This
+setting supports three values: `enable` and `disable` and `check-only`.
+
+* `disable` will ensure that no automatic self updating actions are taken.
+* `enable` will mean that `rustup update` and similar commands will also check for, and install, any update to Rustup.
+* `check-only` will cause any automatic self update to check and report on any updates, but not to automatically install them.
+
+Whether `auto-self-update` is `enable` or not, you can request that Rustup
+update itself to the latest version of `rustup` by running `rustup self update`.
+This will not download new toolchains:
 
 ```console
 $ rustup self update
 info: checking for self-updates
 info: downloading self-updates
 ```
 
-> #### Disable automatic self-updates
-> `rustup` will automatically update itself at the end of any toolchain installation.
-> You can prevent this automatic behaviour by passing the `--no-self-update` argument
-> when running `rustup update` or `rustup toolchain install`.
+### Disabling self updates on a per-invocation basis
+> Self updates can also be suppressed on individual invocations of `rustup` by
+> passing the argurment `--no-self-update`  when running `rustup update` or
+> `rustup toolchain install`.
 
 ## Help system
 

src/cli/rustup_mode.rs

@@ -13,7 +13,11 @@ use super::self_update;
 use super::term2;
 use super::term2::Terminal;
 use super::topical_doc;
-use super::{common, self_update::get_available_rustup_version};
+use super::{
+    common,
+    self_update::{check_rustup_update, SelfUpdateMode},
+};
+use crate::cli::errors::CLIError;
 use crate::dist::dist::{
     PartialTargetTriple, PartialToolchainDesc, Profile, TargetTriple, ToolchainDesc,
 };
@@ -185,6 +189,7 @@ pub fn main() -> Result<utils::ExitCode> {
         ("set", Some(c)) => match c.subcommand() {
             ("default-host", Some(m)) => set_default_host_triple(cfg, m)?,
             ("profile", Some(m)) => set_profile(cfg, m)?,
+            ("auto-self-update", Some(m)) => set_auto_self_update(cfg, m)?,
             (_, _) => unreachable!(),
         },
         ("completions", Some(c)) => {
@@ -707,6 +712,16 @@ pub fn cli() -> App<'static, 'static> {
                                 .possible_values(Profile::names())
                                 .default_value(Profile::default_name()),
                         ),
+                )
+                .subcommand(
+                    SubCommand::with_name("auto-self-update")
+                        .about("The rustup auto self update mode")
+                        .arg(
+                            Arg::with_name("auto-self-update-mode")
+                                .required(true)
+                                .possible_values(SelfUpdateMode::modes())
+                                .default_value(SelfUpdateMode::default_mode()),
+                        ),
                 ),
         );
 
@@ -911,31 +926,20 @@ fn check_updates(cfg: &Cfg) -> Result<utils::ExitCode> {
         }
     }
 
-    // Get current rustup version
-    let current_version = env!("CARGO_PKG_VERSION");
-
-    // Get available rustup version
-    let available_version = get_available_rustup_version()?;
+    check_rustup_update()?;
 
-    let _ = t.attr(term2::Attr::Bold);
-    write!(t, "rustup - ")?;
-
-    if current_version != available_version {
-        let _ = t.fg(term2::color::YELLOW);
-        write!(t, "Update available")?;
-        let _ = t.reset();
-        writeln!(t, " : {} -> {}", current_version, available_version)?;
-    } else {
-        let _ = t.fg(term2::color::GREEN);
-        write!(t, "Up to date")?;
-        let _ = t.reset();
-        writeln!(t, " : {}", current_version)?;
-    }
     Ok(utils::ExitCode(0))
 }
 
 fn update(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
-    let self_update = !m.is_present("no-self-update") && !self_update::NEVER_SELF_UPDATE;
+    let self_update_mode = cfg.get_self_update_mode()?;
+    // Priority: no-self-update feature > self_update_mode > no-self-update args.
+    // Update only if rustup does **not** have the no-self-update feature,
+    // and auto-self-update is configured to **enable**
+    // and has **no** no-self-update parameter.
+    let self_update = !self_update::NEVER_SELF_UPDATE
+        && self_update_mode == SelfUpdateMode::Enable
+        && !m.is_present("no-self-update");
     let forced = m.is_present("force-non-host");
     if let Some(p) = m.value_of("profile") {
         let p = Profile::from_str(p)?;
@@ -1021,6 +1025,10 @@ fn update(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
         cfg.temp_cfg.clean();
     }
 
+    if !self_update::NEVER_SELF_UPDATE && self_update_mode == SelfUpdateMode::CheckOnly {
+        check_rustup_update()?;
+    }
+
     Ok(utils::ExitCode(0))
 }
 
@@ -1578,6 +1586,20 @@ fn set_profile(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
     Ok(utils::ExitCode(0))
 }
 
+fn set_auto_self_update(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
+    if self_update::NEVER_SELF_UPDATE {
+        let mut args = crate::process().args_os();
+        let arg0 = args.next().map(PathBuf::from);
+        let arg0 = arg0
+            .as_ref()
+            .and_then(|a| a.to_str())
+            .ok_or(CLIError::NoExeName)?;
+        warn!("{} is built with the no-self-update feature: setting auto-self-update will not have any effect.",arg0);
+    }
+    cfg.set_auto_self_update(&m.value_of("auto-self-update-mode").unwrap())?;
+    Ok(utils::ExitCode(0))
+}
+
 fn show_profile(cfg: &Cfg) -> Result<utils::ExitCode> {
     writeln!(process().stdout(), "{}", cfg.get_profile()?)?;
     Ok(utils::ExitCode(0))

src/cli/self_update.rs

@@ -48,8 +48,10 @@ use std::borrow::Cow;
 use std::env;
 use std::env::consts::EXE_SUFFIX;
 use std::fs;
+use std::io::Write;
 use std::path::{Component, Path, PathBuf, MAIN_SEPARATOR};
 use std::process::Command;
+use std::str::FromStr;
 
 use anyhow::{anyhow, Context, Result};
 use cfg_if::cfg_if;
@@ -59,6 +61,7 @@ use super::common::{self, ignorable_error, Confirm};
 use super::errors::*;
 use super::markdown::md;
 use super::term2;
+use crate::cli::term2::Terminal;
 use crate::dist::dist::{self, Profile, TargetTriple};
 use crate::process;
 use crate::toolchain::{DistributableToolchain, Toolchain};
@@ -86,6 +89,51 @@ pub const NEVER_SELF_UPDATE: bool = true;
 #[cfg(not(feature = "no-self-update"))]
 pub const NEVER_SELF_UPDATE: bool = false;
 
+#[derive(Clone, Debug, PartialEq)]
+pub enum SelfUpdateMode {
+    Enable,
+    Disable,
+    CheckOnly,
+}
+
+impl SelfUpdateMode {
+    pub fn modes() -> &'static [&'static str] {
+        &["enable", "disable", "check-only"]
+    }
+
+    pub fn default_mode() -> &'static str {
+        "enable"
+    }
+}
+
+impl FromStr for SelfUpdateMode {
+    type Err = anyhow::Error;
+
+    fn from_str(mode: &str) -> Result<Self> {
+        match mode {
+            "enable" => Ok(Self::Enable),
+            "disable" => Ok(Self::Disable),
+            "check-only" => Ok(Self::CheckOnly),
+            _ => Err(anyhow!(format!(
+                "unknown self update mode: '{}'; valid modes are {}",
+                mode,
+                valid_self_update_modes(),
+            ))),
+        }
+    }
+}
+
+impl ToString for SelfUpdateMode {
+    fn to_string(&self) -> String {
+        match self {
+            SelfUpdateMode::Enable => "enable",
+            SelfUpdateMode::Disable => "disable",
+            SelfUpdateMode::CheckOnly => "check-only",
+        }
+        .into()
+    }
+}
+
 // The big installation messages. These are macros because the first
 // argument of format! needs to be a literal.
 
@@ -491,7 +539,6 @@ fn do_pre_install_sanity_checks(no_prompt: bool) -> Result<()> {
 }
 
 fn do_pre_install_options_sanity_checks(opts: &InstallOpts<'_>) -> Result<()> {
-    use std::str::FromStr;
     // Verify that the installation options are vaguely sane
     (|| {
         let host_triple = opts
@@ -1103,6 +1150,32 @@ pub fn get_available_rustup_version() -> Result<String> {
     Ok(String::from(available_version))
 }
 
+pub fn check_rustup_update() -> Result<()> {
+    let mut t = term2::stdout();
+    // Get current rustup version
+    let current_version = env!("CARGO_PKG_VERSION");
+
+    // Get available rustup version
+    let available_version = get_available_rustup_version()?;
+
+    let _ = t.attr(term2::Attr::Bold);
+    write!(t, "rustup - ")?;
+
+    if current_version != available_version {
+        let _ = t.fg(term2::color::YELLOW);
+        write!(t, "Update available")?;
+        let _ = t.reset();
+        writeln!(t, " : {} -> {}", current_version, available_version)?;
+    } else {
+        let _ = t.fg(term2::color::GREEN);
+        write!(t, "Up to date")?;
+        let _ = t.reset();
+        writeln!(t, " : {}", current_version)?;
+    }
+
+    Ok(())
+}
+
 pub fn cleanup_self_updater() -> Result<()> {
     let cargo_home = utils::cargo_home()?;
     let setup = cargo_home.join(&format!("bin/rustup-init{}", EXE_SUFFIX));
@@ -1114,6 +1187,14 @@ pub fn cleanup_self_updater() -> Result<()> {
     Ok(())
 }
 
+pub fn valid_self_update_modes() -> String {
+    SelfUpdateMode::modes()
+        .iter()
+        .map(|s| format!("'{}'", s))
+        .collect::<Vec<_>>()
+        .join(", ")
+}
+
 #[cfg(test)]
 mod tests {
     use std::collections::HashMap;

src/config.rs

@@ -11,6 +11,7 @@ use pgp::{Deserializable, SignedPublicKey};
 use serde::Deserialize;
 use thiserror::Error as ThisError;
 
+use crate::cli::self_update::SelfUpdateMode;
 use crate::dist::download::DownloadCfg;
 use crate::dist::{
     dist::{self, valid_profile_names},
@@ -405,6 +406,20 @@ impl Cfg {
         Ok(())
     }
 
+    pub fn set_auto_self_update(&mut self, mode: &str) -> Result<()> {
+        match SelfUpdateMode::from_str(mode) {
+            Ok(update_mode) => {
+                self.settings_file.with_mut(|s| {
+                    s.auto_self_update = Some(update_mode);
+                    Ok(())
+                })?;
+                (self.notify_handler)(Notification::SetSelfUpdate(mode));
+                Ok(())
+            }
+            Err(err) => Err(err),
+        }
+    }
+
     pub fn set_toolchain_override(&mut self, toolchain_override: &str) {
         self.toolchain_override = Some(toolchain_override.to_owned());
     }
@@ -430,6 +445,16 @@ impl Cfg {
         })
     }
 
+    pub fn get_self_update_mode(&self) -> Result<SelfUpdateMode> {
+        self.settings_file.with(|s| {
+            let mode = match &s.auto_self_update {
+                Some(mode) => mode.clone(),
+                None => SelfUpdateMode::Enable,
+            };
+            Ok(mode)
+        })
+    }
+
     pub fn get_toolchain(&self, name: &str, create_parent: bool) -> Result<Toolchain<'_>> {
         if create_parent {
             utils::ensure_dir_exists("toolchains", &self.toolchains_dir, &|n| {

src/notifications.rs

@@ -13,6 +13,7 @@ pub enum Notification<'a> {
     SetDefaultToolchain(&'a str),
     SetOverrideToolchain(&'a Path, &'a str),
     SetProfile(&'a str),
+    SetSelfUpdate(&'a str),
     LookingForToolchain(&'a str),
     ToolchainDirectory(&'a Path, &'a str),
     UpdatingToolchain(&'a str),
@@ -73,6 +74,7 @@ impl<'a> Notification<'a> {
             SetDefaultToolchain(_)
             | SetOverrideToolchain(_, _)
             | SetProfile(_)
+            | SetSelfUpdate(_)
             | UsingExistingToolchain(_)
             | UninstallingToolchain(_)
             | UninstalledToolchain(_)
@@ -102,6 +104,7 @@ impl<'a> Display for Notification<'a> {
                 name
             ),
             SetProfile(name) => write!(f, "profile set to '{}'", name),
+            SetSelfUpdate(mode) => write!(f, "auto-self-update mode set to '{}'", mode),
             LookingForToolchain(name) => write!(f, "looking for installed toolchain '{}'", name),
             ToolchainDirectory(path, _) => write!(f, "toolchain directory: '{}'", path.display()),
             UpdatingToolchain(name) => write!(f, "updating existing install for '{}'", name),