rustup which return err if asking an uninstalled toolchain

Signed-off-by: hi-rustin <rustin.liu@gmail.com>

Author: 0xPoe

src/cli/rustup_mode.rs

@@ -1046,8 +1046,7 @@ fn which(cfg: &Cfg, m: &ArgMatches<'_>) -> Result<utils::ExitCode> {
         cfg.which_binary_by_toolchain(toolchain, binary)?
     } else {
         cfg.which_binary(&utils::current_dir()?, binary)?
-    }
-    .expect("binary not found");
+    };
 
     utils::assert_is_file(&binary_path)?;
 

src/config.rs

@@ -478,20 +478,20 @@ impl Cfg {
 
     pub(crate) fn which_binary_by_toolchain(
         &self,
-        toolchain: &str,
+        toolchain_name: &str,
         binary: &str,
-    ) -> Result<Option<PathBuf>> {
-        let toolchain = self.get_toolchain(toolchain, false)?;
+    ) -> Result<PathBuf> {
+        let toolchain = self.get_toolchain(toolchain_name, false)?;
         if toolchain.exists() {
-            Ok(Some(toolchain.binary_file(binary)))
+            Ok(toolchain.binary_file(binary))
         } else {
-            Ok(None)
+            Err(RustupError::ToolchainNotInstalled(toolchain_name.to_string()).into())
         }
     }
 
-    pub(crate) fn which_binary(&self, path: &Path, binary: &str) -> Result<Option<PathBuf>> {
+    pub(crate) fn which_binary(&self, path: &Path, binary: &str) -> Result<PathBuf> {
         let (toolchain, _) = self.find_or_install_override_toolchain_or_default(path)?;
-        Ok(Some(toolchain.binary_file(binary)))
+        Ok(toolchain.binary_file(binary))
     }
 
     pub(crate) fn upgrade_data(&self) -> Result<()> {

tests/cli-misc.rs

@@ -860,6 +860,36 @@ fn which() {
     });
 }
 
+#[test]
+fn which_asking_uninstalled_toolchain() {
+    setup(&|config| {
+        let path_1 = config.customdir.join("custom-1");
+        let path_1 = path_1.to_string_lossy();
+        expect_ok(
+            config,
+            &["rustup", "toolchain", "link", "custom-1", &path_1],
+        );
+        expect_ok(config, &["rustup", "default", "custom-1"]);
+        #[cfg(windows)]
+        expect_stdout_ok(
+            config,
+            &["rustup", "which", "rustc"],
+            "\\toolchains\\custom-1\\bin\\rustc",
+        );
+        #[cfg(not(windows))]
+        expect_stdout_ok(
+            config,
+            &["rustup", "which", "rustc"],
+            "/toolchains/custom-1/bin/rustc",
+        );
+        expect_err(
+            config,
+            &["rustup", "which", "--toolchain=nightly", "rustc"],
+            "toolchain 'nightly' is not installed",
+        );
+    });
+}
+
 #[test]
 fn override_by_toolchain_on_the_command_line() {
     setup(&|config| {