Rollup merge of rust-lang#129231 - onur-ozkan:improve-submodule-updates, r=Mark-Simulacrum

improve submodule updates

During config parsing, some bootstrap logic (e.g., `download-ci-llvm`) checks certain sources (for `download-ci-llvm`, it's `src/llvm-project`) and acts based on their state. This means that if path is a git submodule, bootstrap needs to update it before checking its state. Otherwise it may make incorrect assumptions by relying on outdated sources. To enable submodule updates during config parsing, we need to move the `update_submodule` function from the `Build` to `Config`, so we can access to it during the parsing process.

Closes rust-lang#122787

Author: matthiaskrgr

src/bootstrap/src/core/build_steps/llvm.rs

@@ -110,7 +110,7 @@ pub fn prebuilt_llvm_config(builder: &Builder<'_>, target: TargetSelection) -> L
 
     // Initialize the llvm submodule if not initialized already.
     // If submodules are disabled, this does nothing.
-    builder.update_submodule("src/llvm-project");
+    builder.config.update_submodule("src/llvm-project");
 
     let root = "src/llvm-project/llvm";
     let out_dir = builder.llvm_out(target);

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

@@ -14,7 +14,7 @@ use std::sync::OnceLock;
 use std::{cmp, env, fs};
 
 use build_helper::exit;
-use build_helper::git::GitConfig;
+use build_helper::git::{output_result, GitConfig};
 use serde::{Deserialize, Deserializer};
 use serde_derive::Deserialize;
 
@@ -2509,6 +2509,123 @@ impl Config {
         }
     }
 
+    /// Given a path to the directory of a submodule, update it.
+    ///
+    /// `relative_path` should be relative to the root of the git repository, not an absolute path.
+    ///
+    /// This *does not* update the submodule if `config.toml` explicitly says
+    /// not to, or if we're not in a git repository (like a plain source
+    /// tarball). Typically [`Build::require_submodule`] should be
+    /// used instead to provide a nice error to the user if the submodule is
+    /// missing.
+    pub(crate) fn update_submodule(&self, relative_path: &str) {
+        if !self.submodules() {
+            return;
+        }
+
+        let absolute_path = self.src.join(relative_path);
+
+        // NOTE: The check for the empty directory is here because when running x.py the first time,
+        // the submodule won't be checked out. Check it out now so we can build it.
+        if !GitInfo::new(false, &absolute_path).is_managed_git_subrepository()
+            && !helpers::dir_is_empty(&absolute_path)
+        {
+            return;
+        }
+
+        // Submodule updating actually happens during in the dry run mode. We need to make sure that
+        // all the git commands below are actually executed, because some follow-up code
+        // in bootstrap might depend on the submodules being checked out. Furthermore, not all
+        // the command executions below work with an empty output (produced during dry run).
+        // Therefore, all commands below are marked with `run_always()`, so that they also run in
+        // dry run mode.
+        let submodule_git = || {
+            let mut cmd = helpers::git(Some(&absolute_path));
+            cmd.run_always();
+            cmd
+        };
+
+        // Determine commit checked out in submodule.
+        let checked_out_hash = output(submodule_git().args(["rev-parse", "HEAD"]).as_command_mut());
+        let checked_out_hash = checked_out_hash.trim_end();
+        // Determine commit that the submodule *should* have.
+        let recorded = output(
+            helpers::git(Some(&self.src))
+                .run_always()
+                .args(["ls-tree", "HEAD"])
+                .arg(relative_path)
+                .as_command_mut(),
+        );
+
+        let actual_hash = recorded
+            .split_whitespace()
+            .nth(2)
+            .unwrap_or_else(|| panic!("unexpected output `{}`", recorded));
+
+        if actual_hash == checked_out_hash {
+            // already checked out
+            return;
+        }
+
+        println!("Updating submodule {relative_path}");
+        self.check_run(
+            helpers::git(Some(&self.src))
+                .run_always()
+                .args(["submodule", "-q", "sync"])
+                .arg(relative_path),
+        );
+
+        // Try passing `--progress` to start, then run git again without if that fails.
+        let update = |progress: bool| {
+            // Git is buggy and will try to fetch submodules from the tracking branch for *this* repository,
+            // even though that has no relation to the upstream for the submodule.
+            let current_branch = output_result(
+                helpers::git(Some(&self.src))
+                    .allow_failure()
+                    .run_always()
+                    .args(["symbolic-ref", "--short", "HEAD"])
+                    .as_command_mut(),
+            )
+            .map(|b| b.trim().to_owned());
+
+            let mut git = helpers::git(Some(&self.src)).allow_failure();
+            git.run_always();
+            if let Ok(branch) = current_branch {
+                // If there is a tag named after the current branch, git will try to disambiguate by prepending `heads/` to the branch name.
+                // This syntax isn't accepted by `branch.{branch}`. Strip it.
+                let branch = branch.strip_prefix("heads/").unwrap_or(&branch);
+                git.arg("-c").arg(format!("branch.{branch}.remote=origin"));
+            }
+            git.args(["submodule", "update", "--init", "--recursive", "--depth=1"]);
+            if progress {
+                git.arg("--progress");
+            }
+            git.arg(relative_path);
+            git
+        };
+        if !self.check_run(&mut update(true)) {
+            self.check_run(&mut update(false));
+        }
+
+        // Save any local changes, but avoid running `git stash pop` if there are none (since it will exit with an error).
+        // diff-index reports the modifications through the exit status
+        let has_local_modifications = !self.check_run(submodule_git().allow_failure().args([
+            "diff-index",
+            "--quiet",
+            "HEAD",
+        ]));
+        if has_local_modifications {
+            self.check_run(submodule_git().args(["stash", "push"]));
+        }
+
+        self.check_run(submodule_git().args(["reset", "-q", "--hard"]));
+        self.check_run(submodule_git().args(["clean", "-qdfx"]));
+
+        if has_local_modifications {
+            self.check_run(submodule_git().args(["stash", "pop"]));
+        }
+    }
+
     #[cfg(feature = "bootstrap-self-test")]
     pub fn check_stage0_version(&self, _program_path: &Path, _component_name: &'static str) {}
 
@@ -2613,19 +2730,23 @@ impl Config {
         asserts: bool,
     ) -> bool {
         let if_unchanged = || {
-            // Git is needed to track modifications here, but tarball source is not available.
-            // If not modified here or built through tarball source, we maintain consistency
-            // with '"if available"'.
-            if !self.rust_info.is_from_tarball()
-                && self
-                    .last_modified_commit(&["src/llvm-project"], "download-ci-llvm", true)
-                    .is_none()
-            {
-                // there are some untracked changes in the given paths.
-                false
-            } else {
-                llvm::is_ci_llvm_available(self, asserts)
+            if self.rust_info.is_from_tarball() {
+                // Git is needed for running "if-unchanged" logic.
+                println!(
+                    "WARNING: 'if-unchanged' has no effect on tarball sources; ignoring `download-ci-llvm`."
+                );
+                return false;
             }
+
+            self.update_submodule("src/llvm-project");
+
+            // Check for untracked changes in `src/llvm-project`.
+            let has_changes = self
+                .last_modified_commit(&["src/llvm-project"], "download-ci-llvm", true)
+                .is_none();
+
+            // Return false if there are untracked changes, otherwise check if CI LLVM is available.
+            if has_changes { false } else { llvm::is_ci_llvm_available(self, asserts) }
         };
 
         match download_ci_llvm {

src/bootstrap/src/core/download.rs

@@ -56,7 +56,7 @@ impl Config {
     /// Returns false if do not execute at all, otherwise returns its
     /// `status.success()`.
     pub(crate) fn check_run(&self, cmd: &mut BootstrapCommand) -> bool {
-        if self.dry_run() {
+        if self.dry_run() && !cmd.run_always {
             return true;
         }
         self.verbose(|| println!("running: {cmd:?}"));

src/bootstrap/src/lib.rs

@@ -473,117 +473,6 @@ impl Build {
         build
     }
 
-    /// Given a path to the directory of a submodule, update it.
-    ///
-    /// `relative_path` should be relative to the root of the git repository, not an absolute path.
-    ///
-    /// This *does not* update the submodule if `config.toml` explicitly says
-    /// not to, or if we're not in a git repository (like a plain source
-    /// tarball). Typically [`Build::require_submodule`] should be
-    /// used instead to provide a nice error to the user if the submodule is
-    /// missing.
-    fn update_submodule(&self, relative_path: &str) {
-        if !self.config.submodules() {
-            return;
-        }
-
-        let absolute_path = self.config.src.join(relative_path);
-
-        // NOTE: The check for the empty directory is here because when running x.py the first time,
-        // the submodule won't be checked out. Check it out now so we can build it.
-        if !GitInfo::new(false, &absolute_path).is_managed_git_subrepository()
-            && !dir_is_empty(&absolute_path)
-        {
-            return;
-        }
-
-        // Submodule updating actually happens during in the dry run mode. We need to make sure that
-        // all the git commands below are actually executed, because some follow-up code
-        // in bootstrap might depend on the submodules being checked out. Furthermore, not all
-        // the command executions below work with an empty output (produced during dry run).
-        // Therefore, all commands below are marked with `run_always()`, so that they also run in
-        // dry run mode.
-        let submodule_git = || {
-            let mut cmd = helpers::git(Some(&absolute_path));
-            cmd.run_always();
-            cmd
-        };
-
-        // Determine commit checked out in submodule.
-        let checked_out_hash =
-            submodule_git().args(["rev-parse", "HEAD"]).run_capture_stdout(self).stdout();
-        let checked_out_hash = checked_out_hash.trim_end();
-        // Determine commit that the submodule *should* have.
-        let recorded = helpers::git(Some(&self.src))
-            .run_always()
-            .args(["ls-tree", "HEAD"])
-            .arg(relative_path)
-            .run_capture_stdout(self)
-            .stdout();
-        let actual_hash = recorded
-            .split_whitespace()
-            .nth(2)
-            .unwrap_or_else(|| panic!("unexpected output `{}`", recorded));
-
-        if actual_hash == checked_out_hash {
-            // already checked out
-            return;
-        }
-
-        println!("Updating submodule {relative_path}");
-        helpers::git(Some(&self.src))
-            .run_always()
-            .args(["submodule", "-q", "sync"])
-            .arg(relative_path)
-            .run(self);
-
-        // Try passing `--progress` to start, then run git again without if that fails.
-        let update = |progress: bool| {
-            // Git is buggy and will try to fetch submodules from the tracking branch for *this* repository,
-            // even though that has no relation to the upstream for the submodule.
-            let current_branch = helpers::git(Some(&self.src))
-                .allow_failure()
-                .run_always()
-                .args(["symbolic-ref", "--short", "HEAD"])
-                .run_capture_stdout(self)
-                .stdout_if_ok()
-                .map(|s| s.trim().to_owned());
-
-            let mut git = helpers::git(Some(&self.src)).allow_failure();
-            git.run_always();
-            if let Some(branch) = current_branch {
-                // If there is a tag named after the current branch, git will try to disambiguate by prepending `heads/` to the branch name.
-                // This syntax isn't accepted by `branch.{branch}`. Strip it.
-                let branch = branch.strip_prefix("heads/").unwrap_or(&branch);
-                git.arg("-c").arg(format!("branch.{branch}.remote=origin"));
-            }
-            git.args(["submodule", "update", "--init", "--recursive", "--depth=1"]);
-            if progress {
-                git.arg("--progress");
-            }
-            git.arg(relative_path);
-            git
-        };
-        if !update(true).run(self) {
-            update(false).run(self);
-        }
-
-        // Save any local changes, but avoid running `git stash pop` if there are none (since it will exit with an error).
-        // diff-index reports the modifications through the exit status
-        let has_local_modifications =
-            !submodule_git().allow_failure().args(["diff-index", "--quiet", "HEAD"]).run(self);
-        if has_local_modifications {
-            submodule_git().args(["stash", "push"]).run(self);
-        }
-
-        submodule_git().args(["reset", "-q", "--hard"]).run(self);
-        submodule_git().args(["clean", "-qdfx"]).run(self);
-
-        if has_local_modifications {
-            submodule_git().args(["stash", "pop"]).run(self);
-        }
-    }
-
     /// Updates a submodule, and exits with a failure if submodule management
     /// is disabled and the submodule does not exist.
     ///
@@ -598,7 +487,7 @@ impl Build {
         if cfg!(test) && !self.config.submodules() {
             return;
         }
-        self.update_submodule(submodule);
+        self.config.update_submodule(submodule);
         let absolute_path = self.config.src.join(submodule);
         if dir_is_empty(&absolute_path) {
             let maybe_enable = if !self.config.submodules()
@@ -646,7 +535,7 @@ impl Build {
             let path = Path::new(submodule);
             // Don't update the submodule unless it's already been cloned.
             if GitInfo::new(false, path).is_managed_git_subrepository() {
-                self.update_submodule(submodule);
+                self.config.update_submodule(submodule);
             }
         }
     }
@@ -659,7 +548,7 @@ impl Build {
         }
 
         if GitInfo::new(false, Path::new(submodule)).is_managed_git_subrepository() {
-            self.update_submodule(submodule);
+            self.config.update_submodule(submodule);
         }
     }