Rollup merge of #118220 - onur-ozkan:followups, r=Mark-Simulacrum

general improvements/fixes on bootstrap

- adds #117813 into change tracker https://github.com/rust-lang/rust/pull/118220/commits/6d9b92f83fc024d4e86fc90436860903829289bb
- fixes a bug in change tracker https://github.com/rust-lang/rust/pull/118220/commits/63a44109525d7ead76390cf50024939b2118b5ba
- relocates `CONFIG_CHANGE_HISTORY` https://github.com/rust-lang/rust/pull/118220/commits/a7dcb984f644eaa56d91028abcc6e71c2cc2511b

6 files changed, 99 insertions, 88 deletions

diff --git a/src/bootstrap/README.md b/src/bootstrap/README.md
index e7998a40a65..d0a069f45e1 100644
--- a/src/bootstrap/README.md
+++ b/src/bootstrap/README.md
@@ -183,7 +183,7 @@ Some general areas that you may be interested in modifying are:
 
 If you make a major change on bootstrap configuration, please remember to:
 
-+ Update `CONFIG_CHANGE_HISTORY` in `src/bootstrap/lib.rs`.
++ Update `CONFIG_CHANGE_HISTORY` in `src/bootstrap/src/utils/change_tracker.rs`.
 * Update `change-id = {pull-request-id}` in `config.example.toml`.
 
 A 'major change' includes
diff --git a/src/bootstrap/src/bin/main.rs b/src/bootstrap/src/bin/main.rs
index 7e6fdb7092d..952ef40ed42 100644
--- a/src/bootstrap/src/bin/main.rs
+++ b/src/bootstrap/src/bin/main.rs
@@ -120,7 +120,7 @@ fn check_version(config: &Config) -> Option<String> {
         }
 
         if let Ok(last_warned_id) = fs::read_to_string(&warned_id_path) {
-            if id.to_string() == last_warned_id {
+            if latest_change_id.to_string() == last_warned_id {
                 return None;
             }
         }
@@ -144,7 +144,7 @@ fn check_version(config: &Config) -> Option<String> {
             ));
 
             if io::stdout().is_terminal() {
-                t!(fs::write(warned_id_path, id.to_string()));
+                t!(fs::write(warned_id_path, latest_change_id.to_string()));
             }
         }
     } else {
diff --git a/src/bootstrap/src/core/build_steps/setup.rs b/src/bootstrap/src/core/build_steps/setup.rs
index bbbdb4c3186..49373177abe 100644
--- a/src/bootstrap/src/core/build_steps/setup.rs
+++ b/src/bootstrap/src/core/build_steps/setup.rs
@@ -1,6 +1,7 @@
 use crate::core::builder::{Builder, RunConfig, ShouldRun, Step};
+use crate::t;
+use crate::utils::change_tracker::CONFIG_CHANGE_HISTORY;
 use crate::Config;
-use crate::{t, CONFIG_CHANGE_HISTORY};
 use sha2::Digest;
 use std::env::consts::EXE_SUFFIX;
 use std::fmt::Write as _;
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 736a9b312f0..480dd757915 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -47,9 +47,10 @@ use crate::utils::helpers::{self, dir_is_empty, exe, libdir, mtime, output, syml
 mod core;
 mod utils;
 
-pub use crate::core::builder::PathSet;
-pub use crate::core::config::flags::Subcommand;
-pub use crate::core::config::Config;
+pub use core::builder::PathSet;
+pub use core::config::flags::Subcommand;
+pub use core::config::Config;
+pub use utils::change_tracker::{find_recent_config_change_ids, CONFIG_CHANGE_HISTORY};
 
 const LLVM_TOOLS: &[&str] = &[
     "llvm-cov",      // used to generate coverage report
@@ -70,62 +71,6 @@ const LLVM_TOOLS: &[&str] = &[
 /// LLD file names for all flavors.
 const LLD_FILE_NAMES: &[&str] = &["ld.lld", "ld64.lld", "lld-link", "wasm-ld"];
 
-#[derive(Clone, Debug)]
-pub struct ChangeInfo {
-    /// Represents the ID of PR caused major change on bootstrap.
-    pub change_id: usize,
-    pub severity: ChangeSeverity,
-    /// Provides a short summary of the change that will guide developers
-    /// on "how to handle/behave" in response to the changes.
-    pub summary: &'static str,
-}
-
-#[derive(Clone, Debug)]
-pub enum ChangeSeverity {
-    /// Used when build configurations continue working as before.
-    Info,
-    /// Used when the default value of an option changes, or support for an option is removed entirely,
-    /// potentially requiring developers to update their build configurations.
-    Warning,
-}
-
-impl ToString for ChangeSeverity {
-    fn to_string(&self) -> String {
-        match self {
-            ChangeSeverity::Info => "INFO".to_string(),
-            ChangeSeverity::Warning => "WARNING".to_string(),
-        }
-    }
-}
-
-/// Keeps track of major changes made to the bootstrap configuration.
-///
-/// If you make any major changes (such as adding new values or changing default values),
-/// please ensure adding `ChangeInfo` to the end(because the list must be sorted by the merge date)
-/// of this list.
-pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
-    ChangeInfo {
-        change_id: 115898,
-        severity: ChangeSeverity::Info,
-        summary: "Implementation of this change-tracking system. Ignore this.",
-    },
-    ChangeInfo {
-        change_id: 116998,
-        severity: ChangeSeverity::Info,
-        summary: "Removed android-ndk r15 support in favor of android-ndk r25b.",
-    },
-    ChangeInfo {
-        change_id: 117435,
-        severity: ChangeSeverity::Info,
-        summary: "New option `rust.parallel-compiler` added to config.toml.",
-    },
-    ChangeInfo {
-        change_id: 116881,
-        severity: ChangeSeverity::Warning,
-        summary: "Default value of `download-ci-llvm` was changed for `codegen` profile.",
-    },
-];
-
 /// Extra --check-cfg to add when building
 /// (Mode restriction, config name, config values (if any))
 const EXTRA_CHECK_CFGS: &[(Option<Mode>, &str, Option<&[&'static str]>)] = &[
@@ -1895,31 +1840,6 @@ fn envify(s: &str) -> String {
         .collect()
 }
 
-pub fn find_recent_config_change_ids(current_id: usize) -> Vec<ChangeInfo> {
-    if !CONFIG_CHANGE_HISTORY.iter().any(|config| config.change_id == current_id) {
-        // If the current change-id is greater than the most recent one, return
-        // an empty list (it may be due to switching from a recent branch to an
-        // older one); otherwise, return the full list (assuming the user provided
-        // the incorrect change-id by accident).
-        if let Some(config) = CONFIG_CHANGE_HISTORY.iter().max_by_key(|config| config.change_id) {
-            if &current_id > &config.change_id {
-                return Vec::new();
-            }
-        }
-
-        return CONFIG_CHANGE_HISTORY.to_vec();
-    }
-
-    let index =
-        CONFIG_CHANGE_HISTORY.iter().position(|config| config.change_id == current_id).unwrap();
-
-    CONFIG_CHANGE_HISTORY
-        .iter()
-        .skip(index + 1) // Skip the current_id and IDs before it
-        .cloned()
-        .collect()
-}
-
 /// Computes a hash representing the state of a repository/submodule and additional input.
 ///
 /// It uses `git diff` for the actual changes, and `git status` for including the untracked
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
new file mode 100644
index 00000000000..887b596b786
--- /dev/null
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -0,0 +1,89 @@
+//! This module facilitates the tracking system for major changes made to the bootstrap,
+//! with the goal of keeping developers synchronized with important modifications in
+//! the bootstrap.
+
+#[derive(Clone, Debug)]
+pub struct ChangeInfo {
+    /// Represents the ID of PR caused major change on bootstrap.
+    pub change_id: usize,
+    pub severity: ChangeSeverity,
+    /// Provides a short summary of the change that will guide developers
+    /// on "how to handle/behave" in response to the changes.
+    pub summary: &'static str,
+}
+
+#[derive(Clone, Debug)]
+pub enum ChangeSeverity {
+    /// Used when build configurations continue working as before.
+    Info,
+    /// Used when the default value of an option changes, or support for an option is removed entirely,
+    /// potentially requiring developers to update their build configurations.
+    Warning,
+}
+
+impl ToString for ChangeSeverity {
+    fn to_string(&self) -> String {
+        match self {
+            ChangeSeverity::Info => "INFO".to_string(),
+            ChangeSeverity::Warning => "WARNING".to_string(),
+        }
+    }
+}
+
+pub fn find_recent_config_change_ids(current_id: usize) -> Vec<ChangeInfo> {
+    if !CONFIG_CHANGE_HISTORY.iter().any(|config| config.change_id == current_id) {
+        // If the current change-id is greater than the most recent one, return
+        // an empty list (it may be due to switching from a recent branch to an
+        // older one); otherwise, return the full list (assuming the user provided
+        // the incorrect change-id by accident).
+        if let Some(config) = CONFIG_CHANGE_HISTORY.iter().max_by_key(|config| config.change_id) {
+            if &current_id > &config.change_id {
+                return Vec::new();
+            }
+        }
+
+        return CONFIG_CHANGE_HISTORY.to_vec();
+    }
+
+    let index =
+        CONFIG_CHANGE_HISTORY.iter().position(|config| config.change_id == current_id).unwrap();
+
+    CONFIG_CHANGE_HISTORY
+        .iter()
+        .skip(index + 1) // Skip the current_id and IDs before it
+        .cloned()
+        .collect()
+}
+
+/// Keeps track of major changes made to the bootstrap configuration.
+///
+/// If you make any major changes (such as adding new values or changing default values),
+/// please ensure adding `ChangeInfo` to the end(because the list must be sorted by the merge date)
+/// of this list.
+pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
+    ChangeInfo {
+        change_id: 115898,
+        severity: ChangeSeverity::Info,
+        summary: "Implementation of this change-tracking system. Ignore this.",
+    },
+    ChangeInfo {
+        change_id: 116998,
+        severity: ChangeSeverity::Info,
+        summary: "Removed android-ndk r15 support in favor of android-ndk r25b.",
+    },
+    ChangeInfo {
+        change_id: 117435,
+        severity: ChangeSeverity::Info,
+        summary: "New option `rust.parallel-compiler` added to config.toml.",
+    },
+    ChangeInfo {
+        change_id: 116881,
+        severity: ChangeSeverity::Warning,
+        summary: "Default value of `download-ci-llvm` was changed for `codegen` profile.",
+    },
+    ChangeInfo {
+        change_id: 117813,
+        severity: ChangeSeverity::Info,
+        summary: "Use of the `if-available` value for `download-ci-llvm` is deprecated; prefer using the new `if-unchanged` value.",
+    },
+];
diff --git a/src/bootstrap/src/utils/mod.rs b/src/bootstrap/src/utils/mod.rs
index 8ca22d00865..cb535f0e163 100644
--- a/src/bootstrap/src/utils/mod.rs
+++ b/src/bootstrap/src/utils/mod.rs
@@ -4,6 +4,7 @@
 
 pub(crate) mod cache;
 pub(crate) mod cc_detect;
+pub(crate) mod change_tracker;
 pub(crate) mod channel;
 pub(crate) mod dylib;
 pub(crate) mod exec;