Merge pull request #164 from brson/cargo-fallback

Cargo fallback

Author: alexcrichton

src/multirust-cli/rustup_mode.rs

@@ -222,10 +222,9 @@ fn update(cfg: &Cfg, m: &ArgMatches) -> Result<()> {
 
 fn run(cfg: &Cfg, m: &ArgMatches) -> Result<()> {
     let ref toolchain = m.value_of("toolchain").expect("");
-    let ref toolchain = try!(cfg.get_toolchain(toolchain, false));
     let args = m.values_of("command").unwrap();
     let args: Vec<_> = args.collect();
-    let cmd = try!(toolchain.create_command(args[0]));
+    let cmd = try!(cfg.create_command_for_toolchain(toolchain, args[0]));
 
     common::run_inner(cmd, &args)
 }

src/multirust/config.rs

@@ -336,8 +336,52 @@ impl Cfg {
     }
 
     pub fn create_command_for_dir(&self, path: &Path, binary: &str) -> Result<Command> {
-        let (toolchain, _) = try!(self.toolchain_for_dir(path));
-        toolchain.create_command(binary)
+        let (ref toolchain, _) = try!(self.toolchain_for_dir(path));
+
+        if let Some(cmd) = try!(self.maybe_do_cargo_fallback(toolchain, binary)) {
+            Ok(cmd)
+        } else {
+            toolchain.create_command(binary)
+        }
+    }
+
+    pub fn create_command_for_toolchain(&self, toolchain: &str, binary: &str) -> Result<Command> {
+        let ref toolchain = try!(self.get_toolchain(toolchain, false));
+
+        if let Some(cmd) = try!(self.maybe_do_cargo_fallback(toolchain, binary)) {
+            Ok(cmd)
+        } else {
+            toolchain.create_command(binary)
+        }
+    }
+
+    // Custom toolchains don't have cargo, so here we detect that situation and
+    // try to find a different cargo.
+    fn maybe_do_cargo_fallback(&self, toolchain: &Toolchain, binary: &str) -> Result<Option<Command>> {
+        if !toolchain.is_custom() {
+            return Ok(None);
+        }
+
+        if binary != "cargo" && binary != "cargo.exe" {
+            return Ok(None);
+        }
+
+        let cargo_path = toolchain.path().join("bin/cargo");
+        let cargo_exe_path = toolchain.path().join("bin/cargo.exe");
+
+        if cargo_path.exists() || cargo_exe_path.exists() {
+            return Ok(None);
+        }
+
+        for fallback in &["nightly", "beta", "stable"] {
+            let fallback = try!(self.get_toolchain(fallback, false));
+            if fallback.exists() {
+                let cmd = try!(fallback.create_fallback_command("cargo", toolchain));
+                return Ok(Some(cmd));
+            }
+        }
+
+        Ok(None)
     }
 
     pub fn doc_path_for_dir(&self, path: &Path, relative: &str) -> Result<PathBuf> {

src/multirust/toolchain.rs

@@ -229,14 +229,22 @@ impl<'a> Toolchain<'a> {
             return Err(Error::ToolchainNotInstalled(self.name.to_owned()));
         }
 
-        let mut cmd = Command::new(binary);
+        let ref bin_path = self.path.join("bin").join(binary.as_ref());
+        let mut cmd = Command::new(bin_path);
         self.set_env(&mut cmd);
         Ok(cmd)
     }
 
-    fn set_env(&self, cmd: &mut Command) {
-        let ref bin_path = self.path.join("bin");
+    // Create a command as a fallback for another toolchain. This is used
+    // to give custom toolchains access to cargo
+    pub fn create_fallback_command<T: AsRef<OsStr>>(&self, binary: T,
+                                                    primary_toolchain: &Toolchain) -> Result<Command> {
+        let mut cmd = try!(self.create_command(binary));
+        cmd.env("MULTIRUST_TOOLCHAIN", &primary_toolchain.name);
+        Ok(cmd)
+    }
 
+    fn set_env(&self, cmd: &mut Command) {
         self.set_ldpath(cmd);
 
         // Because multirust and cargo use slightly different
@@ -247,12 +255,9 @@ impl<'a> Toolchain<'a> {
             cmd.env("CARGO_HOME", &cargo_home);
         }
 
-        env_var::set_path("PATH", bin_path, cmd);
         env_var::inc("RUST_RECURSION_COUNT", cmd);
 
-        // FIXME: This should not be a path, but a toolchain name.
-        // Not sure what's going on here.
-        cmd.env("MULTIRUST_TOOLCHAIN", &self.path);
+        cmd.env("MULTIRUST_TOOLCHAIN", &self.name);
         cmd.env("MULTIRUST_HOME", &self.cfg.multirust_dir);
     }
 

tests/cli-misc.rs

@@ -671,3 +671,54 @@ fn multi_host_smoke_test() {
                          "xxxx-n-2"); // cross-host mocks have their own versions
     });
 }
+
+#[test]
+fn custom_toolchain_cargo_fallback_proxy() {
+    setup(&|config| {
+        let path = config.customdir.join("custom-1");
+
+        expect_ok(config, &["rustup", "toolchain", "link", "mytoolchain",
+                            &path.to_string_lossy()]);
+        expect_ok(config, &["rustup", "default", "mytoolchain"]);
+
+        expect_ok(config, &["rustup", "update", "stable"]);
+        expect_stdout_ok(config, &["cargo", "--version"],
+                         "hash-s-2");
+
+        expect_ok(config, &["rustup", "update", "beta"]);
+        expect_stdout_ok(config, &["cargo", "--version"],
+                         "hash-b-2");
+
+        expect_ok(config, &["rustup", "update", "nightly"]);
+        expect_stdout_ok(config, &["cargo", "--version"],
+                         "hash-n-2");
+    });
+}
+
+#[test]
+fn custom_toolchain_cargo_fallback_run() {
+    setup(&|config| {
+        let path = config.customdir.join("custom-1");
+
+        expect_ok(config, &["rustup", "toolchain", "link", "mytoolchain",
+                            &path.to_string_lossy()]);
+        expect_ok(config, &["rustup", "default", "mytoolchain"]);
+
+        expect_ok(config, &["rustup", "update", "stable"]);
+        expect_stdout_ok(config, &["rustup", "run", "mytoolchain",
+                                   "cargo", "--version"],
+                         "hash-s-2");
+
+        expect_ok(config, &["rustup", "update", "beta"]);
+        expect_stdout_ok(config, &["rustup", "run", "mytoolchain",
+                                   "cargo", "--version"],
+                         "hash-b-2");
+
+        expect_ok(config, &["rustup", "update", "nightly"]);
+        expect_stdout_ok(config, &["rustup", "run", "mytoolchain",
+                                   "cargo", "--version"],
+                         "hash-n-2");
+
+    });
+}
+