From ab704f43bb8fdea492d7ece0eb45cfdd60a52fc4 Mon Sep 17 00:00:00 2001
From: A4-Tacks <wdsjxhno1001@163.com>
Date: Fri, 17 Apr 2026 18:38:58 +0800
Subject: [PATCH] internal: support RUSTFMT_TOOLCHAIN for xtask codegen

---
 src/tools/rust-analyzer/xtask/src/codegen.rs | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/tools/rust-analyzer/xtask/src/codegen.rs b/src/tools/rust-analyzer/xtask/src/codegen.rs
index bc7eb88f3a84..482b31e306ca 100644
--- a/src/tools/rust-analyzer/xtask/src/codegen.rs
+++ b/src/tools/rust-analyzer/xtask/src/codegen.rs
@@ -130,16 +130,17 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 fn reformat(text: String) -> String {
     let sh = Shell::new().unwrap();
     let rustfmt_toml = project_root().join("rustfmt.toml");
-    let version = cmd!(sh, "rustup run stable rustfmt --version").read().unwrap_or_default();
+    let toolchain = &std::env::var("RUSTFMT_TOOLCHAIN").unwrap_or("stable".to_owned());
+    let version = cmd!(sh, "rustup run {toolchain} rustfmt --version").read().unwrap_or_default();
 
     // First try explicitly requesting the stable channel via rustup in case nightly is being used by default,
     // then plain rustfmt in case rustup isn't being used to manage the compiler (e.g. when using Nix).
-    let mut stdout = if !version.contains("stable") {
+    let mut stdout = if !version.contains(toolchain) {
         let version = cmd!(sh, "rustfmt --version").read().unwrap_or_default();
-        if !version.contains("stable") {
+        if !version.contains(toolchain) {
             panic!(
-                "Failed to run rustfmt from toolchain 'stable'. \
-                 Please run `rustup component add rustfmt --toolchain stable` to install it.",
+                "Failed to run rustfmt from toolchain '{toolchain}'. \
+                 Please run `rustup component add rustfmt --toolchain {toolchain}` to install it.",
             );
         } else {
             cmd!(sh, "rustfmt --config-path {rustfmt_toml} --config fn_single_line=true")
@@ -150,7 +151,7 @@ fn reformat(text: String) -> String {
     } else {
         cmd!(
             sh,
-            "rustup run stable rustfmt --config-path {rustfmt_toml} --config fn_single_line=true"
+            "rustup run {toolchain} rustfmt --config-path {rustfmt_toml} --config fn_single_line=true"
         )
         .stdin(text)
         .read()