1 files changed, 28 insertions, 0 deletions
diff --git a/lang/rust/files/patch-src_bootstrap_lib.rs b/lang/rust/files/patch-src_bootstrap_lib.rs
new file mode 100644
index 000000000000..081c2056ad2c
--- /dev/null
+++ b/lang/rust/files/patch-src_bootstrap_lib.rs
@@ -0,0 +1,28 @@
+Attempt to fix intermittent "can't find crate for `std`" build failures
+
+The location of rustc (found via env::current_exe()) is used to
+find the right libstd.  However it might have been "copied" by
+creating a hard link to the new location instead.  Like /proc/curproc/file,
+KERN_PROC_PATHNAME (used internally by current_exe()) can return
+any of the file's multiple paths.  Most of the time it returns the
+right rustc path and the build will succeed but occasionally it
+will return the "wrong" path and the build fails with:
+
+    error[E0463]: can't find crate for `std`
+
+If this is right a viable workaround should be to never create hard
+links during the build, so let's try that.
+
+--- src/bootstrap/lib.rs.orig	2020-07-23 20:16:43 UTC
++++ src/bootstrap/lib.rs
+@@ -1173,10 +1173,6 @@ impl Build {
+         if metadata.file_type().is_symlink() {
+             let link = t!(fs::read_link(src));
+             t!(symlink_file(link, dst));
+-        } else if let Ok(()) = fs::hard_link(src, dst) {
+-            // 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.
+         } else {
+             if let Err(e) = fs::copy(src, dst) {
+                 panic!("failed to copy `{}` to `{}`: {}", src.display(), dst.display(), e)