Auto merge of #12283 - epage:build, r=weihanglo

fix(embedded): Don't auto-discover build.rs files

With #12268, we moved the manifest root to be the scripts parent
directory, making it so auto-discovery might pick some things up.

We previously ensured `auto*` don't pick things up but missed `build.rs`
This is now addressed.

src/cargo/util/toml/embedded.rs

@@ -89,6 +89,9 @@ fn expand_manifest_(
         ));
         toml::Value::String(DEFAULT_EDITION.to_string())
     });
+    package
+        .entry("build".to_owned())
+        .or_insert_with(|| toml::Value::Boolean(false));
     package
         .entry("publish".to_owned())
         .or_insert_with(|| toml::Value::Boolean(DEFAULT_PUBLISH));

tests/testsuite/script.rs

@@ -509,6 +509,35 @@ fn main() {
         .run();
 }
 
+#[cargo_test]
+fn test_no_build_rs() {
+    let script = r#"#!/usr/bin/env cargo
+
+fn main() {
+    println!("Hello world!");
+}"#;
+    let p = cargo_test_support::project()
+        .file("script.rs", script)
+        .file("build.rs", "broken")
+        .build();
+
+    p.cargo("-Zscript script.rs --help")
+        .masquerade_as_nightly_cargo(&["script"])
+        .with_stdout(
+            r#"Hello world!
+"#,
+        )
+        .with_stderr(
+            "\
+[WARNING] `package.edition` is unspecifiead, defaulting to `2021`
+[COMPILING] script v0.0.0 ([ROOT]/foo)
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]s
+[RUNNING] `[..]/debug/script[EXE] --help`
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn test_no_autobins() {
     let script = r#"#!/usr/bin/env cargo