rustbuild: Use copies instead of hard links

src/bootstrap/util.rs

@@ -20,6 +20,8 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::time::Instant;
 
+use filetime::{self, FileTime};
+
 /// Returns the `name` as the filename of a static library for `target`.
 pub fn staticlib(name: &str, target: &str) -> String {
  if target.contains("windows") {
@@ -38,12 +40,18 @@ pub fn copy(src: &Path, dst: &Path) {
 
  // Attempt to "easy copy" by creating a hard link (symlinks don't work on
  // windows), but if that fails just fall back to a slow `copy` operation.
- let res = fs::hard_link(src, dst);
- let res = res.or_else(|_| fs::copy(src, dst).map(|_| ()));
+ // let res = fs::hard_link(src, dst);
+ let res = fs::copy(src, dst);
  if let Err(e) = res {
  panic!("failed to copy `{}` to `{}`: {}", src.display(),
  dst.display(), e)
  }
+ let metadata = t!(src.metadata());
+ t!(fs::set_permissions(dst, metadata.permissions()));
+ let atime = FileTime::from_last_access_time(&metadata);
+ let mtime = FileTime::from_last_modification_time(&metadata);
+ t!(filetime::set_file_times(dst, atime, mtime));
+
 }
 
 /// Copies the `src` directory recursively to `dst`. Both are assumed to exist

src/librustc_metadata/locator.rs

@@ -639,6 +639,34 @@ impl<'a> Context<'a> {
  lib.display()));
  continue;
  }
+
+ // Ok so at this point we've determined that `(lib, kind)` above is
+ // a candidate crate to load, and that `slot` is either none (this
+ // is the first crate of its kind) or if some the previous path has
+ // the exact same hash (e.g. it's the exact same crate).
+ //
+ // In principle these two candidate crates are exactly the same so
+ // we can choose either of them to link. As a stupidly gross hack,
+ // however, we favor crate in the sysroot.
+ //
+ // You can find more info in rust-lang/rust#39518 and various linked
+ // issues, but the general gist is that during testing libstd the
+ // compilers has two candidates to choose from: one in the sysroot
+ // and one in the deps folder. These two crates are the exact same
+ // crate but if the compiler chooses the one in the deps folder
+ // it'll cause spurious errors on Windows.
+ //
+ // As a result, we favor the sysroot crate here. Note that the
+ // candidates are all canonicalized, so we canonicalize the sysroot
+ // as well.
+ if let Some((ref prev, _)) = ret {
+ let sysroot = self.sess.sysroot();
+ let sysroot = sysroot.canonicalize()
+ .unwrap_or(sysroot.to_path_buf());
+ if prev.starts_with(&sysroot) {
+ continue
+ }
+ }
  *slot = Some((hash, metadata));
  ret = Some((lib, kind));
  }

src/stage0.txt

@@ -13,4 +13,4 @@
 # released on `$date`
 
 rustc: beta-2017-02-01
-cargo: bfee18f73287687c543bda8c35e4e33808792715
+cargo: 407edef22e894266eb562618cba5ca9757051946