ci: single arm64 debian-13 build host; ThinLTO everywhere; baseline-only x64; rust+link merge; sysroots; WebKit a36c188; rust 2026-07-20

.buildkite/scripts/upload-release.sh

@@ -296,14 +296,10 @@ function create_release() {
     bun-linux-aarch64-profile.zip
     bun-linux-x64.zip
     bun-linux-x64-profile.zip
-    bun-linux-x64-baseline.zip
-    bun-linux-x64-baseline-profile.zip
     bun-linux-aarch64-musl.zip
     bun-linux-aarch64-musl-profile.zip
     bun-linux-x64-musl.zip
     bun-linux-x64-musl-profile.zip
-    bun-linux-x64-musl-baseline.zip
-    bun-linux-x64-musl-baseline-profile.zip
     bun-linux-aarch64-android.zip
     bun-linux-aarch64-android-profile.zip
     bun-linux-x64-android.zip
@@ -314,15 +310,48 @@ function create_release() {
     bun-freebsd-x64-profile.zip
     bun-windows-x64.zip
     bun-windows-x64-profile.zip
-    bun-windows-x64-baseline.zip
-    bun-windows-x64-baseline-profile.zip
     bun-windows-aarch64.zip
     bun-windows-aarch64-profile.zip
   )
 
-  function upload_artifact() {
+  # x64 ships one nehalem binary under the plain name. Re-zip it under the
+  # historical `-baseline` name (inner dir renamed) so older `bun upgrade`
+  # clients that still request `-baseline` extract correctly.
+  function alias_baseline_artifact() {
+    local artifact="$1"
+    case "$artifact" in
+      bun-darwin-x64.zip)              echo "bun-darwin-x64-baseline.zip" ;;
+      bun-darwin-x64-profile.zip)      echo "bun-darwin-x64-baseline-profile.zip" ;;
+      bun-linux-x64.zip)               echo "bun-linux-x64-baseline.zip" ;;
+      bun-linux-x64-profile.zip)       echo "bun-linux-x64-baseline-profile.zip" ;;
+      bun-linux-x64-musl.zip)          echo "bun-linux-x64-musl-baseline.zip" ;;
+      bun-linux-x64-musl-profile.zip)  echo "bun-linux-x64-musl-baseline-profile.zip" ;;
+      bun-windows-x64.zip)             echo "bun-windows-x64-baseline.zip" ;;
+      bun-windows-x64-profile.zip)     echo "bun-windows-x64-baseline-profile.zip" ;;
+      *)                               echo "" ;;
+    esac
+  }
+
+  command -v unzip &> /dev/null || package_manager_install unzip
+  command -v zip &> /dev/null || package_manager_install zip
+
+  # Repack `$src_zip` (inner dir = basename of $src_zip) as `$dst_zip` with the
+  # inner dir renamed to match `$dst_zip`'s basename. Works in a fresh mktemp
+  # dir so a caller-CWD change can't collide with the extracted names.
+  function rezip_as() {
+    local src_zip="$1" dst_zip="$2"
+    local src_dir="${src_zip%.zip}" dst_dir="${dst_zip%.zip}"
+    local abs_src="$PWD/$src_zip" abs_dst="$PWD/$dst_zip"
+    local work; work="$(mktemp -d)"
+    run_command unzip -q -d "$work" "$abs_src"
+    run_command mv "$work/$src_dir" "$work/$dst_dir"
+    run_command rm -f "$abs_dst"
+    (cd "$work" && run_command zip -rq "$abs_dst" "$dst_dir")
+    run_command rm -rf "$work"
+  }
+
+  function upload_one() {
     local artifact="$1"
-    download_buildkite_artifact "$artifact"
     if [ "$tag" == "canary" ]; then
       upload_s3_file "releases/$BUILDKITE_COMMIT-canary" "$artifact" &
     else
@@ -333,6 +362,17 @@ function create_release() {
     wait
   }
 
+  function upload_artifact() {
+    local artifact="$1"
+    download_buildkite_artifact "$artifact"
+    upload_one "$artifact"
+    local alias="$(alias_baseline_artifact "$artifact")"
+    if [ -n "$alias" ]; then
+      rezip_as "$artifact" "$alias"
+      upload_one "$alias"
+    fi
+  }
+
   for artifact in "${artifacts[@]}"; do
     upload_artifact "$artifact"
   done

.github/workflows/clippy.yml

@@ -28,7 +28,7 @@ env:
   # Pin the toolchain explicitly so rustup ignores rust-toolchain.toml's
   # `targets` list (11 cross triples ≈ 450 MB of prebuilt std we don't need
   # to lint the host). Keep in sync with `channel` in rust-toolchain.toml.
-  RUSTUP_TOOLCHAIN: nightly-2026-05-06
+  RUSTUP_TOOLCHAIN: nightly-2026-07-20
 
 jobs:
   clippy:

.github/workflows/format.yml

@@ -40,7 +40,7 @@ jobs:
           # Pin the toolchain explicitly so rustup ignores rust-toolchain.toml's
           # `targets` list (11 cross triples ≈ 450 MB of prebuilt std we don't
           # need just to run rustfmt). Keep this in sync with `channel` there.
-          RUSTUP_TOOLCHAIN: nightly-2026-05-06
+          RUSTUP_TOOLCHAIN: nightly-2026-07-20
         run: |
           # Without pipefail, `cmd | sed` always reports sed's exit status, so a
           # failing formatter is invisible to the `wait $PID` checks below.

.github/workflows/miri.yml

@@ -37,7 +37,7 @@ env:
   LLVM_VERSION_MAJOR: "21"
   # Pin so rustup ignores rust-toolchain.toml's `targets` list (11 cross
   # triples ≈ 450 MB we don't need). Keep in sync with `channel` there.
-  RUSTUP_TOOLCHAIN: nightly-2026-05-06
+  RUSTUP_TOOLCHAIN: nightly-2026-07-20
 
 jobs:
   miri:

packages/bun-release/src/platform.ts

@@ -1,22 +1,19 @@
 import { debug } from "./console";
-import { exists, read } from "./fs";
+import { exists } from "./fs";
 import { spawn } from "./spawn";
 
 export const os = process.platform;
 
 export const arch = os === "darwin" && process.arch === "x64" && isRosetta2() ? "arm64" : process.arch;
 
-export const avx2 =
-  arch === "x64" &&
-  ((os === "linux" && isLinuxAVX2()) || (os === "darwin" && isDarwinAVX2()) || (os === "win32" && isWindowsAVX2()));
-
 export const abi = os === "android" ? "android" : os === "linux" && isLinuxMusl() ? "musl" : undefined;
 
 export type Platform = {
   os: string;
   arch: string;
   abi?: "musl" | "android";
-  avx2?: boolean;
+  /** Back-compat alias package; same binary as the plain entry. Skipped by the postinstall picker. */
+  alias?: boolean;
   bin: string;
   exe: string;
 };
@@ -31,13 +28,13 @@ export const platforms: Platform[] = [
   {
     os: "darwin",
     arch: "x64",
-    avx2: true,
     bin: "bun-darwin-x64",
     exe: "bin/bun",
   },
   {
     os: "darwin",
     arch: "x64",
+    alias: true,
     bin: "bun-darwin-x64-baseline",
     exe: "bin/bun",
   },
@@ -50,13 +47,13 @@ export const platforms: Platform[] = [
   {
     os: "linux",
     arch: "x64",
-    avx2: true,
     bin: "bun-linux-x64",
     exe: "bin/bun",
   },
   {
     os: "linux",
     arch: "x64",
+    alias: true,
     bin: "bun-linux-x64-baseline",
     exe: "bin/bun",
   },
@@ -71,14 +68,14 @@ export const platforms: Platform[] = [
     os: "linux",
     arch: "x64",
     abi: "musl",
-    avx2: true,
     bin: "bun-linux-x64-musl",
     exe: "bin/bun",
   },
   {
     os: "linux",
     arch: "x64",
     abi: "musl",
+    alias: true,
     bin: "bun-linux-x64-musl-baseline",
     exe: "bin/bun",
   },
@@ -115,13 +112,13 @@ export const platforms: Platform[] = [
   {
     os: "win32",
     arch: "x64",
-    avx2: true,
     bin: "bun-windows-x64",
     exe: "bin/bun.exe",
   },
   {
     os: "win32",
     arch: "x64",
+    alias: true,
     bin: "bun-windows-x64-baseline",
     exe: "bin/bun.exe",
   },
@@ -133,15 +130,10 @@ export const platforms: Platform[] = [
   },
 ];
 
-export const supportedPlatforms: Platform[] = platforms
-  .filter(
-    platform =>
-      platform.os === os &&
-      platform.arch === arch &&
-      (!platform.avx2 || avx2) &&
-      (!platform.abi || abi === platform.abi),
-  )
-  .sort((a, b) => (a.avx2 === b.avx2 ? 0 : a.avx2 ? -1 : 1));
+export const supportedPlatforms: Platform[] = platforms.filter(
+  platform =>
+    platform.os === os && platform.arch === arch && !platform.alias && (!platform.abi || abi === platform.abi),
+);
 
 function isLinuxMusl(): boolean {
   try {
@@ -152,25 +144,6 @@ function isLinuxMusl(): boolean {
   }
 }
 
-function isLinuxAVX2(): boolean {
-  try {
-    return read("/proc/cpuinfo").includes("avx2");
-  } catch (error) {
-    debug("isLinuxAVX2 failed", error);
-    return false;
-  }
-}
-
-function isDarwinAVX2(): boolean {
-  try {
-    const { exitCode, stdout } = spawn("sysctl", ["-n", "machdep.cpu"]);
-    return exitCode === 0 && stdout.includes("AVX2");
-  } catch (error) {
-    debug("isDarwinAVX2 failed", error);
-    return false;
-  }
-}
-
 function isRosetta2(): boolean {
   try {
     const { exitCode, stdout } = spawn("sysctl", ["-n", "sysctl.proc_translated"]);
@@ -180,17 +153,3 @@ function isRosetta2(): boolean {
     return false;
   }
 }
-
-function isWindowsAVX2(): boolean {
-  try {
-    return (
-      spawn("powershell", [
-        "-c",
-        `(Add-Type -MemberDefinition '[DllImport("kernel32.dll")] public static extern bool IsProcessorFeaturePresent(int ProcessorFeature);' -Name 'Kernel32' -Namespace 'Win32' -PassThru)::IsProcessorFeaturePresent(40);`,
-      ]).stdout.trim() === "True"
-    );
-  } catch (error) {
-    debug("isWindowsAVX2 failed", error);
-    return false;
-  }
-}

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "nightly-2026-05-06"
+channel = "nightly-2026-07-20"
 # rust-src is needed for -Zbuild-std (Tier 3 targets like
 # aarch64-unknown-freebsd have no prebuilt std). miri is for
 # `bun run rust:miri`. targets ensures the