address comments

address comments

doc/src/basics.md

@@ -40,15 +40,15 @@ This is the essence of `rustup`.
 
 ## Keeping rustup up to date
 
-We control the automatic update of rustup by setting the auto-self-update configuration. 
-The auto-self-update setting supports three values: `enable` and `disable` and `check-only`.
+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`.
 
-When it is `enable`, running `rustup update` will also check for updates to `rustup` and automatically install the latest version.
-If it is `disable`, the available updates is not checked and installed. 
-In addition, you can set auto-self-update to `check-only` if you want to check rustup for available updates during `rustup update` as well.
+* `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.
 
-To manually force check for updates and install the
-latest version of `rustup` without updating installed toolchains type `rustup
+Whether automatic self-update is enabled or not, you can request that Rustup check for, and update it self to the
+latest version of `rustup` without updating any installed toolchains by running `rustup
 self update`:
 
 ```console

src/cli/rustup_mode.rs

@@ -932,6 +932,7 @@ fn check_updates(cfg: &Cfg) -> Result<utils::ExitCode> {
 
 fn update(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
     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.
@@ -1023,7 +1024,7 @@ fn update(cfg: &mut Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
         cfg.temp_cfg.clean();
     }
 
-    if !self_update && self_update_mode == "check-only" {
+    if !self_update::NEVER_SELF_UPDATE && self_update_mode == "check-only" {
         check_rustup_update()?;
     }
 

src/config.rs

@@ -406,6 +406,7 @@ impl Cfg {
         Ok(())
     }
 
+    // FIXME(hi-rustin): It is better to use enumerations rather than strings.
     pub fn set_auto_self_update(&mut self, mode: &str) -> Result<()> {
         if !SELF_UPDATE_MODES.contains(&mode) {
             return Err(anyhow!(

src/notifications.rs

@@ -104,7 +104,7 @@ impl<'a> Display for Notification<'a> {
                 name
             ),
             SetProfile(name) => write!(f, "profile set to '{}'", name),
-            SetSelfUpdate(mode) => write!(f, "self update mode to '{}'", mode),
+            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),