Simplify Toolchain::from_local()

Author: djc

src/toolchain/distributable.rs

@@ -27,7 +27,7 @@ use super::{
 /// An official toolchain installed on the local disk
 #[derive(Debug)]
 pub(crate) struct DistributableToolchain<'a> {
-    toolchain: Toolchain<'a>,
+    pub(super) toolchain: Toolchain<'a>,
     cfg: &'a Cfg<'a>,
     desc: ToolchainDesc,
 }

src/toolchain/toolchain.rs

@@ -43,35 +43,20 @@ impl<'a> Toolchain<'a> {
         install_if_missing: bool,
         cfg: &'a Cfg<'a>,
     ) -> anyhow::Result<Toolchain<'a>> {
-        match toolchain_name {
-            LocalToolchainName::Named(ToolchainName::Official(desc)) => {
-                match DistributableToolchain::new(cfg, desc.clone()) {
-                    Err(RustupError::ToolchainNotInstalled(_)) => {
-                        if install_if_missing {
-                            DistributableToolchain::install(
-                                cfg,
-                                desc,
-                                &[],
-                                &[],
-                                cfg.get_profile()?,
-                                true,
-                            )
-                            .await?;
-                        }
-                    }
-                    o => {
-                        o?;
-                    }
-                }
-            }
-            n => {
-                if !Self::exists(cfg, n)? {
-                    return Err(RustupError::ToolchainNotInstallable(n.to_string()).into());
-                }
+        match Self::new(cfg, toolchain_name.clone()) {
+            Ok(tc) => Ok(tc),
+            Err(RustupError::ToolchainNotInstalled(ToolchainName::Official(desc)))
+                if install_if_missing =>
+            {
+                Ok(
+                    DistributableToolchain::install(cfg, &desc, &[], &[], cfg.get_profile()?, true)
+                        .await?
+                        .1
+                        .toolchain,
+                )
             }
+            Err(e) => Err(e.into()),
         }
-
-        Ok(Self::new(cfg, toolchain_name.clone())?)
     }
 
     pub(crate) async fn from_partial(

tests/suite/cli_exact.rs

@@ -685,7 +685,7 @@ fn undefined_linked_toolchain() {
             config.expect_err_ex(
                 &["cargo", "+bogus", "test"],
                 r"",
-                "error: toolchain 'bogus' is not installable\n",
+                "error: toolchain 'bogus' is not installed\n",
             );
         })
     });

tests/suite/cli_rustup.rs

@@ -2450,7 +2450,7 @@ fn non_utf8_toolchain() {
                 [OsStr::from_bytes(b"+\xc3\x28")],
                 &[("RUST_BACKTRACE", "1")],
             );
-            assert!(out.stderr.contains("toolchain '�(' is not installable"));
+            assert!(out.stderr.contains("toolchain '�(' is not installed"));
         })
     });
 }
@@ -2469,7 +2469,7 @@ fn non_utf8_toolchain() {
                 [OsString::from_wide(&[u16::from(b'+'), 0xd801, 0xd801])],
                 &[("RUST_BACKTRACE", "1")],
             );
-            assert!(out.stderr.contains("toolchain '��' is not installable"));
+            assert!(out.stderr.contains("toolchain '��' is not installed"));
         })
     });
 }