sort dump files at the end of bootstrap

To ensure deterministic results we must sort the dump lines.
This is necessary because the order of rustc invocations different
almost all the time.

Signed-off-by: onur-ozkan <work@onurozkan.dev>

Author: onur-ozkan

src/bootstrap/src/bin/main.rs

@@ -10,8 +10,9 @@ use std::io::Write;
 #[cfg(all(any(unix, windows), not(target_os = "solaris")))]
 use std::process;
 use std::{
-    env, fs,
-    io::{self, IsTerminal},
+    env,
+    fs::{self, OpenOptions},
+    io::{self, BufRead, BufReader, IsTerminal},
 };
 
 use bootstrap::{
@@ -79,6 +80,9 @@ fn main() {
     }
 
     let pre_commit = config.src.join(".git").join("hooks").join("pre-commit");
+    let dump_bootstrap_shims = config.dump_bootstrap_shims;
+    let out_dir = config.out.clone();
+
     Build::new(config).build();
 
     if suggest_setup {
@@ -107,6 +111,29 @@ fn main() {
     if suggest_setup || changelog_suggestion.is_some() {
         println!("NOTE: this message was printed twice to make it more likely to be seen");
     }
+
+    if dump_bootstrap_shims {
+        let dump_dir = out_dir.join("bootstrap-shims-dump");
+        assert!(dump_dir.exists());
+
+        for entry in walkdir::WalkDir::new(&dump_dir) {
+            let entry = t!(entry);
+
+            if !entry.file_type().is_file() {
+                continue;
+            }
+
+            let file = t!(fs::File::open(&entry.path()));
+
+            // To ensure deterministic results we must sort the dump lines.
+            // This is necessary because the order of rustc invocations different
+            // almost all the time.
+            let mut lines: Vec<String> = t!(BufReader::new(&file).lines().collect());
+            lines.sort_by_key(|t| t.to_lowercase());
+            let mut file = t!(OpenOptions::new().write(true).truncate(true).open(&entry.path()));
+            t!(file.write_all(lines.join("\n").as_bytes()));
+        }
+    }
 }
 
 fn check_version(config: &Config) -> Option<String> {