optimize

Author: liwagu

src/bootstrap/src/core/build_steps/tool.rs

@@ -1,8 +1,6 @@
 use std::path::PathBuf;
 use std::{env, fs};
 
-use build_helper::git::get_closest_merge_commit;
-
 use crate::core::build_steps::compile;
 use crate::core::build_steps::toolstate::ToolState;
 use crate::core::builder;
@@ -596,19 +594,14 @@ impl Step for Rustdoc {
             && target_compiler.stage > 0
             && builder.rust_info().is_managed_git_subrepository()
         {
-            let commit = get_closest_merge_commit(
-                Some(&builder.config.src),
-                &builder.config.git_config(),
-                &[],
-            )
-            .unwrap();
 
-            let dirs = vec![
-                builder.config.src.join("src/librustdoc"),
-                builder.config.src.join("src/tools/rustdoc"),
+            let files_to_track = &[
+                "src/librustdoc",
+                "src/tools/rustdoc",
             ];
-            let has_changes = builder.config.check_for_changes(&dirs, &commit);
-            if !has_changes {
+            
+            if builder.config.last_modified_commit(files_to_track, "rustdoc", true).is_some() {
+                // if return Some(commit)，means unchanged
                 let precompiled_rustdoc = builder
                     .config
                     .ci_rustc_dir()

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

@@ -2759,8 +2759,19 @@ impl Config {
 
         // Look for a version to compare to based on the current commit.
         // Only commits merged by bors will have CI artifacts.
-        let commit =
-            self.last_modified_commit(files_to_track, "download-rustc", if_unchanged).unwrap();
+        let commit = match self.last_modified_commit(files_to_track, "download-rustc", if_unchanged) {
+            Some(commit) => commit,
+            None => {
+                if if_unchanged{
+                    return None;
+                }
+                println!("ERROR: could not find commit hash for downloading rustc");
+                println!("HELP: maybe your repository history is too shallow?");
+                println!("HELP: consider disabling `download-rustc`");
+                println!("HELP: or fetch enough history to include one upstream commit");
+                crate::exit!(1);
+            }
+        };
 
         if CiEnv::is_ci() && {
             let head_sha =
@@ -2775,7 +2786,7 @@ impl Config {
             return None;
         }
 
-        Some(commit.to_string())
+        Some(commit)
     }
 
     fn parse_download_ci_llvm(