Rollup merge of #52969 - Keruspe:local_rebuild, r=alexcrichton

rustbuild: fix local_rebuild

If we detect a local rebuild (e.g. bootstrap compiler is the same version as target compiler), we set stage to 1.
When trying to build e.g. UnstableBook, we use Mode::ToolBootstrap and stage is 1.
Just allow Mode::ToolBootstrap and stagge != 0 if we are in a local_rebuild

This fixes building current master using current beta (as master hasn't yet been bumped to 1.30).
This should be backported to beta too, as currently we cannot build beta using itself because of that.

r? @alexcrichton

1 files changed, 1 insertions, 1 deletions

diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 724d3b74190..dc0b0aaf0bb 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -777,7 +777,7 @@ impl<'a> Builder<'a> {
         // compiler, but for tools we just use the precompiled libraries that
         // we've downloaded
         let use_snapshot = mode == Mode::ToolBootstrap;
-        assert!(!use_snapshot || stage == 0);
+        assert!(!use_snapshot || stage == 0 || self.local_rebuild);
 
         let maybe_sysroot = self.sysroot(compiler);
         let sysroot = if use_snapshot {