Auto merge of rust-lang#138201 - jieyouxu:bootstrap-cycle, r=<try>

[DO NOT MERGE] debugging bootstrap cycle (too)

r? ghost

try-job: aarch64-apple

Author: bors

src/bootstrap/bootstrap.py

@@ -1130,8 +1130,9 @@ def build_bootstrap_cmd(self, env):
         ]
         args.extend("--verbose" for _ in range(self.verbose))
 
-        if "BOOTSTRAP_TRACING" in env:
-            args.append("--features=tracing")
+        #if "BOOTSTRAP_TRACING" in env:
+        args.append("--features=tracing")
+        env["BOOTSTRAP_TRACING"] = "bootstrap=trace"
 
         if self.use_locked_deps:
             args.append("--locked")

src/bootstrap/src/core/builder/mod.rs

@@ -1500,6 +1500,7 @@ impl<'a> Builder<'a> {
                 let mut out = String::new();
                 out += &format!("\n\nCycle in build detected when adding {step:?}\n");
                 for el in stack.iter().rev() {
+                    let el = el as &dyn Any;
                     out += &format!("\t{el:?}\n");
                 }
                 panic!("{}", out);

src/bootstrap/src/core/config/config.rs

@@ -48,6 +48,7 @@ pub(crate) const RUSTC_IF_UNCHANGED_ALLOWED_PATHS: &[&str] = &[
     ":!src/rustdoc-json-types",
     ":!tests",
     ":!triagebot.toml",
+    ":!src/bootstrap",
 ];
 
 macro_rules! check_ci_llvm {