Rollup merge of #37265 - brson:bootstrap, r=alexcrichton

Allow bootstrapping without a key. Fixes #36548

This will make it easier for packagers to bootstrap rustc when they happen
to have a bootstrap compiler with a slightly different version number.

It's not ok for anything other than the build system to set this environment variable.

r? @alexcrichton

5 files changed, 14 insertions, 24 deletions

diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index b8d0eb3ff99..af76a49fed0 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -214,7 +214,7 @@ pub fn compiletest(build: &Build,
             }
         }
     }
-    build.add_bootstrap_key(compiler, &mut cmd);
+    build.add_bootstrap_key(&mut cmd);
 
     cmd.arg("--adb-path").arg("adb");
     cmd.arg("--adb-test-dir").arg(ADB_TEST_DIR);
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index 418c3a48ed3..ff8e4757bd1 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -119,7 +119,7 @@ fn build_startup_objects(build: &Build, target: &str, into: &Path) {
     for file in t!(fs::read_dir(build.src.join("src/rtstartup"))) {
         let file = t!(file);
         let mut cmd = Command::new(&compiler_path);
-        build.add_bootstrap_key(&compiler, &mut cmd);
+        build.add_bootstrap_key(&mut cmd);
         build.run(cmd.arg("--target").arg(target)
                      .arg("--emit=obj")
                      .arg("--out-dir").arg(into)
@@ -185,7 +185,6 @@ pub fn rustc<'a>(build: &'a Build, target: &str, compiler: &Compiler<'a>) {
     cargo.env("CFG_RELEASE", &build.release)
          .env("CFG_RELEASE_CHANNEL", &build.config.channel)
          .env("CFG_VERSION", &build.version)
-         .env("CFG_BOOTSTRAP_KEY", &build.bootstrap_key)
          .env("CFG_PREFIX", build.config.prefix.clone().unwrap_or(String::new()))
          .env("CFG_LIBDIR_RELATIVE", "lib");
 
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 30983869c2e..a63c23b4621 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -662,7 +662,7 @@ impl Build {
              .env("RUSTDOC_REAL", self.rustdoc(compiler))
              .env("RUSTC_FLAGS", self.rustc_flags(target).join(" "));
 
-        self.add_bootstrap_key(compiler, &mut cargo);
+        self.add_bootstrap_key(&mut cargo);
 
         // Specify some various options for build scripts used throughout
         // the build.
@@ -871,16 +871,11 @@ impl Build {
     }
 
     /// Adds the compiler's bootstrap key to the environment of `cmd`.
-    fn add_bootstrap_key(&self, compiler: &Compiler, cmd: &mut Command) {
-        // In stage0 we're using a previously released stable compiler, so we
-        // use the stage0 bootstrap key. Otherwise we use our own build's
-        // bootstrap key.
-        let bootstrap_key = if compiler.is_snapshot(self) && !self.local_rebuild {
-            &self.bootstrap_key_stage0
-        } else {
-            &self.bootstrap_key
-        };
-        cmd.env("RUSTC_BOOTSTRAP_KEY", bootstrap_key);
+    fn add_bootstrap_key(&self, cmd: &mut Command) {
+        cmd.env("RUSTC_BOOTSTRAP", "");
+        // FIXME: Transitionary measure to bootstrap using the old bootstrap logic.
+        // Remove this once the bootstrap compiler uses the new login in Issue #36548.
+        cmd.env("RUSTC_BOOTSTRAP_KEY", "62b3e239");
     }
 
     /// Returns the compiler's libdir where it stores the dynamic libraries that
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 9e5dfdc30c8..954fe330b54 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -1330,15 +1330,12 @@ impl UnstableFeatures {
     pub fn from_environment() -> UnstableFeatures {
         // Whether this is a feature-staged build, i.e. on the beta or stable channel
         let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some();
-        // The secret key needed to get through the rustc build itself by
-        // subverting the unstable features lints
-        let bootstrap_secret_key = option_env!("CFG_BOOTSTRAP_KEY");
-        // The matching key to the above, only known by the build system
-        let bootstrap_provided_key = env::var("RUSTC_BOOTSTRAP_KEY").ok();
-        match (disable_unstable_features, bootstrap_secret_key, bootstrap_provided_key) {
-            (_, Some(ref s), Some(ref p)) if s == p => UnstableFeatures::Cheat,
-            (true, _, _) => UnstableFeatures::Disallow,
-            (false, _, _) => UnstableFeatures::Allow
+        // Whether we should enable unstable features for bootstrapping
+        let bootstrap = env::var("RUSTC_BOOTSTRAP").is_ok();
+        match (disable_unstable_features, bootstrap) {
+            (_, true) => UnstableFeatures::Cheat,
+            (true, _) => UnstableFeatures::Disallow,
+            (false, _) => UnstableFeatures::Allow
         }
     }
 
diff --git a/src/stage0.txt b/src/stage0.txt
index 05189f2011b..ac2050a6fc8 100644
--- a/src/stage0.txt
+++ b/src/stage0.txt
@@ -13,5 +13,4 @@
 # released on `$date`
 
 rustc: beta-2016-09-28
-rustc_key: 62b3e239
 cargo: nightly-2016-09-26