Reduce uname usage

CHANGELOG.md

@@ -27,6 +27,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
       # tool: rust@nightly + rustfmt + wasm32-wasip1
   ```
 
+- Fix issue where x86_64 binary will be installed on AArch64 Windows even when AArch64 Windows binary available.
+
 ## [2.76.0] - 2026-05-04
 
 - Support `mdbook-d2`. ([#1737](https://github.com/taiki-e/install-action/pull/1737), thanks @nhu)

action.yml

@@ -54,6 +54,8 @@ runs:
         INPUT_FALLBACK: ${{ inputs.fallback }}
         DEFAULT_GITHUB_TOKEN: ${{ inputs.fallback == 'cargo-binstall' && github.token || '' }}
         ACTION_USER_AGENT: ${{ github.action_repository }} (${{ github.action_ref }})
+        RUNNER_OS: ${{ runner.os }}
+        RUNNER_ARCH: ${{ runner.arch }}
       if: runner.os != 'Windows'
     # Use pwsh and retry on bash startup failure to work around windows-11-arm runner bug:
     # https://github.com/actions/partner-runner-images/issues/169
@@ -88,4 +90,6 @@ runs:
         INPUT_FALLBACK: ${{ inputs.fallback }}
         DEFAULT_GITHUB_TOKEN: ${{ inputs.fallback == 'cargo-binstall' && github.token || '' }}
         ACTION_USER_AGENT: ${{ github.action_repository }} (${{ github.action_ref }})
+        RUNNER_OS: ${{ runner.os }}
+        RUNNER_ARCH: ${{ runner.arch }}
       if: runner.os == 'Windows'

main.sh

@@ -515,10 +515,13 @@ token="${GITHUB_TOKEN:-"${GH_TOKEN:-"${DEFAULT_GITHUB_TOKEN:-}"}"}"
 # via `ps -Eww` on macOS. It only reduces the risk of leaks.
 unset GITHUB_TOKEN GH_TOKEN DEFAULT_GITHUB_TOKEN
 
-# Refs: https://github.com/rust-lang/rustup/blob/HEAD/rustup-init.sh
+# Refs:
+# - https://github.com/rust-lang/rustup/blob/HEAD/rustup-init.sh
+# - https://docs.github.com/en/actions/reference/workflows-and-actions/contexts#runner-context
+# NB: Sync with tools/ci/tool-list.sh.
 base_distro=''
 exe=''
-case "$(uname -s)" in
+case "${RUNNER_OS}" in
   Linux)
     host_os=linux
     ldd_version=$(ldd --version 2>&1 || true)
@@ -568,16 +571,15 @@ case "$(uname -s)" in
         ;;
     esac
     ;;
-  Darwin) host_os=macos ;;
+  macOS) host_os=macos ;;
-  MINGW* | MSYS* | CYGWIN* | Windows_NT)
+  Windows)
     host_os=windows
     exe=.exe
     ;;
-  *) bail "unrecognized OS type '$(uname -s)'" ;;
+  *) bail "unrecognized runner.os '${RUNNER_OS}'" ;;
 esac
-# NB: Sync with tools/ci/tool-list.sh.
+case "${RUNNER_ARCH}" in
-case "$(uname -m)" in
+  X64) host_arch=x86_64 ;;
-  aarch64 | arm64) host_arch=aarch64 ;;
   # Ignore 32-bit Arm for now, as we need to consider the version and whether hard-float is supported.
   # https://github.com/rust-lang/rustup/pull/593
   # https://github.com/cross-rs/cross/pull/1018
@@ -586,6 +588,16 @@ case "$(uname -m)" in
   # Does it seem only armv7l+ is supported?
   # https://github.com/actions/runner/blob/v2.321.0/src/Misc/externals.sh#L178
   # https://github.com/actions/runner/issues/688
+  ARM) bail "32-bit Arm runner is currently not supported by this action; if you need support for this platform, please submit an issue at <https://github.com/taiki-e/install-action>" ;;
+  X86) bail "32-bit x86 runner is currently not supported by this action; if you need support for this platform, please submit an issue at <https://github.com/taiki-e/install-action>" ;;
+  ARM64) host_arch=aarch64 ;;
+  PPC64LE) host_arch=powerpc64le ;;
+  RISCV64) host_arch=riscv64 ;;
+  S390X) host_arch=s390x ;;
+  *)
+    info "unrecognized runner.arch '${RUNNER_ARCH}'; fallback to uname -m"
+    case "$(uname -m)" in
+      aarch64 | arm64) host_arch=aarch64 ;;
       xscale | arm | armv*l) bail "32-bit Arm runner is not supported yet by this action; if you need support for this platform, please submit an issue at <https://github.com/taiki-e/install-action>" ;;
       ppc64le) host_arch=powerpc64le ;;
       riscv64) host_arch=riscv64 ;;
@@ -599,9 +611,10 @@ case "$(uname -m)" in
       # And IBM provides runners for powerpc64le/s390x Linux.
       # https://github.com/IBM/actionspz
       # So we can assume x86_64 unless it has a known non-x86_64 uname -m result.
-  # TODO: uname -m on windows-11-arm returns "x86_64"
       *) host_arch=x86_64 ;;
     esac
+    ;;
+esac
 info "host platform: ${host_arch}_${host_os}"
 
 home="${HOME:-}"