Auto merge of #1337 - nrc:ui-missing-tool, r=alexcrichton

Warn when tools are missing and allow to override

Closes #1277

Idea here is to not update if the RLS is missing (for example). There was actually functionality to do this already, but it was not catching the RLS and Rustfmt since they were missing in an unexpected way.

The second commit adds `rustup update --force` to update even if some components are missing

r? @alexcrichton

src/rustup-cli/common.rs

@@ -189,9 +189,9 @@ fn show_channel_updates(cfg: &Cfg, toolchains: Vec<(String, rustup::Result<Updat
     Ok(())
 }
 
-pub fn update_all_channels(cfg: &Cfg, self_update: bool) -> Result<()> {
+pub fn update_all_channels(cfg: &Cfg, self_update: bool, force_update: bool) -> Result<()> {
 
-    let toolchains = try!(cfg.update_all_channels());
+    let toolchains = try!(cfg.update_all_channels(force_update));
 
     if toolchains.is_empty() {
         info!("no updatable toolchains installed");

src/rustup-cli/rustup_mode.rs

@@ -144,7 +144,11 @@ pub fn cli() -> App<'static, 'static> {
                 .help("Don't perform self update when running the `rustup` command")
                 .long("no-self-update")
                 .takes_value(false)
-                .hidden(true)))
+                .hidden(true))
+            .arg(Arg::with_name("force")
+                .help("Force an update, even if some components are missing")
+                .long("force")
+                .takes_value(false)))
         .subcommand(SubCommand::with_name("default")
             .about("Set the default toolchain")
             .after_help(DEFAULT_HELP)
@@ -462,7 +466,7 @@ fn update(cfg: &Cfg, m: &ArgMatches) -> Result<()> {
             let toolchain = try!(cfg.get_toolchain(name, false));
 
             let status = if !toolchain.is_custom() {
-                Some(try!(toolchain.install_from_dist()))
+                Some(try!(toolchain.install_from_dist(m.is_present("force"))))
             } else if !toolchain.exists() {
                 return Err(ErrorKind::ToolchainNotInstalled(toolchain.name().to_string()).into());
             } else {
@@ -475,7 +479,11 @@ fn update(cfg: &Cfg, m: &ArgMatches) -> Result<()> {
             }
         }
     } else {
-        try!(common::update_all_channels(cfg, !m.is_present("no-self-update") && !self_update::NEVER_SELF_UPDATE));
+        try!(common::update_all_channels(
+            cfg,
+            !m.is_present("no-self-update") && !self_update::NEVER_SELF_UPDATE,
+            m.is_present("force"),
+        ));
     }
 
     Ok(())

src/rustup-cli/self_update.rs

@@ -747,7 +747,7 @@ fn maybe_install_rust(toolchain_str: &str, default_host_triple: &str, verbose: b
         // Set host triple first as it will affect resolution of toolchain_str
         try!(cfg.set_default_host_triple(default_host_triple));
         let toolchain = try!(cfg.get_toolchain(toolchain_str, false));
-        let status = try!(toolchain.install_from_dist());
+        let status = try!(toolchain.install_from_dist(false));
         try!(cfg.set_default(toolchain_str));
         println!("");
         try!(common::show_channel_update(cfg, toolchain_str, Ok(status)));

src/rustup-dist/src/dist.rs

@@ -462,7 +462,8 @@ pub fn update_from_dist<'a>(download: DownloadCfg<'a>,
                             toolchain: &ToolchainDesc,
                             prefix: &InstallPrefix,
                             add: &[Component],
-                            remove: &[Component])
+                            remove: &[Component],
+                            force_update: bool)
                             -> Result<Option<String>> {
 
     let fresh_install = !prefix.path().exists();
@@ -472,7 +473,8 @@ pub fn update_from_dist<'a>(download: DownloadCfg<'a>,
                                 toolchain,
                                 prefix,
                                 add,
-                                remove);
+                                remove,
+                                force_update);
 
     // Don't leave behind an empty / broken installation directory
     if res.is_err() && fresh_install {
@@ -485,12 +487,13 @@ pub fn update_from_dist<'a>(download: DownloadCfg<'a>,
 }
 
 pub fn update_from_dist_<'a>(download: DownloadCfg<'a>,
-                            update_hash: Option<&Path>,
-                            toolchain: &ToolchainDesc,
-                            prefix: &InstallPrefix,
-                            add: &[Component],
-                            remove: &[Component])
-                            -> Result<Option<String>> {
+                             update_hash: Option<&Path>,
+                             toolchain: &ToolchainDesc,
+                             prefix: &InstallPrefix,
+                             add: &[Component],
+                             remove: &[Component],
+                             force_update: bool)
+                             -> Result<Option<String>> {
 
     let toolchain_str = toolchain.to_string();
     let manifestation = try!(Manifestation::open(prefix.clone(), toolchain.target.clone()));
@@ -507,6 +510,7 @@ pub fn update_from_dist_<'a>(download: DownloadCfg<'a>,
             (download.notify_handler)(Notification::DownloadedManifest(&m.date, m.get_rust_version().ok()));
             return match try!(manifestation.update(&m,
                                                    changes,
+                                                   force_update,
                                                    &download,
                                                    download.notify_handler.clone())) {
                 UpdateStatus::Unchanged => Ok(None),