From 5d3e8210feabae1d80a9f21c18c9173b1fdc43ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=AE=B8=E6=9D=B0=E5=8F=8B=20Jieyou=20Xu=20=28Joe=29?=
 <39484203+jieyouxu@users.noreply.github.com>
Date: Thu, 17 Oct 2024 22:58:45 +0800
Subject: [PATCH] bootstrap: allow setting `--jobs` in config.toml

(cherry picked from commit 65458aed68fe6786068bab00e5a46d7ecdd2a072)
---
 config.example.toml                       |  5 ++
 src/bootstrap/src/core/config/config.rs   |  5 +-
 src/bootstrap/src/core/config/flags.rs    |  3 +-
 src/bootstrap/src/core/config/tests.rs    | 58 +++++++++++++++++++++++
 src/bootstrap/src/utils/change_tracker.rs |  5 ++
 5 files changed, 73 insertions(+), 3 deletions(-)

diff --git a/config.example.toml b/config.example.toml
index f1dc32234ccf..40c7ac9f5023 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -401,6 +401,11 @@
 # Specify the location of the Android NDK. Used when targeting Android.
 #android-ndk = "/path/to/android-ndk-r26d"
 
+# Number of parallel jobs to be used for building and testing. If set to `0` or
+# omitted, it will be automatically determined. This is the `-j`/`--jobs` flag
+# passed to cargo invocations.
+#jobs = 0
+
 # =============================================================================
 # General install configuration options
 # =============================================================================
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index bdfee55d8d18..c1e0f8c6b338 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -872,6 +872,7 @@ struct Build {
         metrics: Option<bool> = "metrics",
         android_ndk: Option<PathBuf> = "android-ndk",
         optimized_compiler_builtins: Option<bool> = "optimized-compiler-builtins",
+        jobs: Option<u32> = "jobs",
     }
 }
 
@@ -1256,7 +1257,6 @@ pub(crate) fn parse_inner(
         config.rustc_error_format = flags.rustc_error_format;
         config.json_output = flags.json_output;
         config.on_fail = flags.on_fail;
-        config.jobs = Some(threads_from_config(flags.jobs as u32));
         config.cmd = flags.cmd;
         config.incremental = flags.incremental;
         config.dry_run = if flags.dry_run { DryRun::UserSelected } else { DryRun::Disabled };
@@ -1477,8 +1477,11 @@ fn get_table(option: &str) -> Result<TomlConfig, toml::de::Error> {
             metrics: _,
             android_ndk,
             optimized_compiler_builtins,
+            jobs,
         } = toml.build.unwrap_or_default();
 
+        config.jobs = Some(threads_from_config(flags.jobs.unwrap_or(jobs.unwrap_or(0))));
+
         if let Some(file_build) = build {
             config.build = TargetSelection::from_user(&file_build);
         };
diff --git a/src/bootstrap/src/core/config/flags.rs b/src/bootstrap/src/core/config/flags.rs
index c3f174028149..7fdd5f8b8cae 100644
--- a/src/bootstrap/src/core/config/flags.rs
+++ b/src/bootstrap/src/core/config/flags.rs
@@ -110,11 +110,10 @@ pub struct Flags {
         short,
         long,
         value_hint = clap::ValueHint::Other,
-        default_value_t = std::thread::available_parallelism().map_or(1, std::num::NonZeroUsize::get),
         value_name = "JOBS"
     )]
     /// number of jobs to run in parallel
-    pub jobs: usize,
+    pub jobs: Option<u32>,
     // This overrides the deny-warnings configuration option,
     // which passes -Dwarnings to the compiler invocations.
     #[arg(global = true, long)]
diff --git a/src/bootstrap/src/core/config/tests.rs b/src/bootstrap/src/core/config/tests.rs
index 219c5a6ec914..bc49074fa316 100644
--- a/src/bootstrap/src/core/config/tests.rs
+++ b/src/bootstrap/src/core/config/tests.rs
@@ -317,3 +317,61 @@ fn order_of_clippy_rules() {
 
     assert_eq!(expected, actual);
 }
+
+#[test]
+fn parse_jobs() {
+    assert_eq!(parse("build.jobs = 1").jobs, Some(1));
+}
+
+#[test]
+fn jobs_precedence() {
+    // `--jobs` should take precedence over using `--set build.jobs`.
+
+    let config = Config::parse_inner(
+        Flags::parse(&[
+            "check".to_owned(),
+            "--config=/does/not/exist".to_owned(),
+            "--jobs=67890".to_owned(),
+            "--set=build.jobs=12345".to_owned(),
+        ]),
+        |&_| toml::from_str(""),
+    );
+    assert_eq!(config.jobs, Some(67890));
+
+    // `--set build.jobs` should take precedence over `config.toml`.
+    let config = Config::parse_inner(
+        Flags::parse(&[
+            "check".to_owned(),
+            "--config=/does/not/exist".to_owned(),
+            "--set=build.jobs=12345".to_owned(),
+        ]),
+        |&_| {
+            toml::from_str(
+                r#"
+            [build]
+            jobs = 67890
+        "#,
+            )
+        },
+    );
+    assert_eq!(config.jobs, Some(12345));
+
+    // `--jobs` > `--set build.jobs` > `config.toml`
+    let config = Config::parse_inner(
+        Flags::parse(&[
+            "check".to_owned(),
+            "--jobs=123".to_owned(),
+            "--config=/does/not/exist".to_owned(),
+            "--set=build.jobs=456".to_owned(),
+        ]),
+        |&_| {
+            toml::from_str(
+                r#"
+            [build]
+            jobs = 789
+        "#,
+            )
+        },
+    );
+    assert_eq!(config.jobs, Some(123));
+}
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
index 51a25104e4cf..1f6a1064a5dc 100644
--- a/src/bootstrap/src/utils/change_tracker.rs
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -235,4 +235,9 @@ pub fn human_readable_changes(changes: &[ChangeInfo]) -> String {
         severity: ChangeSeverity::Info,
         summary: "The `build.profiler` option now tries to use source code from `download-ci-llvm` if possible, instead of checking out the `src/llvm-project` submodule.",
     },
+    ChangeInfo {
+        change_id: 131838,
+        severity: ChangeSeverity::Info,
+        summary: "Allow setting `--jobs` in config.toml with `build.jobs`.",
+    },
 ];
-- 
2.47.0