Merge pull request #3310 from hi-rustin/rustin-patch-help

Author: 0xPoe

src/cli/rustup_mode.rs

@@ -30,6 +30,10 @@ use crate::utils::utils;
 use crate::Notification;
 use crate::{command, Cfg, ComponentStatus, Toolchain};
 
+const TOOLCHAIN_OVERRIDE_ERROR: &str =
+    "To override the toolchain using the 'rustup +toolchain' syntax, \
+                        make sure to prefix the toolchain override with a '+'";
+
 fn handle_epipe(res: Result<utils::ExitCode>) -> Result<utils::ExitCode> {
     match res {
         Err(e) => {
@@ -110,6 +114,10 @@ pub fn main() -> Result<utils::ExitCode> {
                 write!(process().stdout().lock(), "{err}")?;
                 return Ok(utils::ExitCode(1));
             }
+            if err.kind() == ValueValidation && err.to_string().contains(TOOLCHAIN_OVERRIDE_ERROR) {
+                write!(process().stderr().lock(), "{err}")?;
+                return Ok(utils::ExitCode(1));
+            }
             Err(err)
         }
     }?;
@@ -245,7 +253,9 @@ pub(crate) fn cli() -> Command<'static> {
                     if s.starts_with('+') {
                         Ok(s.to_owned())
                     } else {
-                        Err("Toolchain overrides must begin with '+'".to_owned())
+                        Err(format!(
+                            "\"{s}\" is not a valid subcommand, so it was interpreted as a toolchain name, but it is also invalid. {TOOLCHAIN_OVERRIDE_ERROR}"
+                        ))
                     }
                 }),
         )

tests/suite/cli-ui/rustup/rustup_unknown_arg_stdout.toml

@@ -0,0 +1,9 @@
+bin.name = "rustup"
+args = ["random"]
+status.code = 1
+stdout = ""
+stderr = """
+error: Invalid value \"random\" for '<+toolchain>': \"random\" is not a valid subcommand, so it was interpreted as a toolchain name, but it is also invalid. To override the toolchain using the 'rustup +toolchain' syntax, make sure to prefix the toolchain override with a '+'
+
+For more information try --help
+"""

tests/suite/cli_misc.rs

@@ -944,10 +944,6 @@ fn override_by_toolchain_on_the_command_line() {
             &["rustup", "+foo", "which", "rustc"],
             "toolchain 'foo' is not installed",
         );
-        config.expect_err(
-            &["rustup", "@stable", "which", "rustc"],
-            r#"Invalid value "@stable" for '<+toolchain>': Toolchain overrides must begin with '+'"#,
-        );
         config.expect_stderr_ok(
             &["rustup", "+stable", "set", "profile", "minimal"],
             "profile set to 'minimal'",