From 52839d91bd2bc2ddd013ed76dca9428560852e42 Mon Sep 17 00:00:00 2001
From: Dave Rolsky <autarch@urth.org>
Date: Mon, 20 Jan 2025 20:45:44 -0600
Subject: [PATCH] Fix bug where we would try to use `cross` on ARM hosts for
 all targets

If the target is ARM and the host is ARM, this should work with just `cargo`. I'm not sure if this
works for all ARM host/target combos, or if the CPU architecture must be an exact match.

But it doesn't really matter too much, since at least for now there's no ARM builds for
`cross` (https://github.com/cross-rs/cross/issues/1612). So even if cross-compilation doesn't work
natively, we couldn't use `cross` in this case either.

I also rewrote the `set-cross-compile.sh` in Python. By "I", I mean I had Claude do it and then I
tweaked it.
---
 Changes.md           |  5 +++
 action.yml           |  2 +-
 set-cross-compile.py | 97 ++++++++++++++++++++++++++++++++++++++++++++
 set-cross-compile.sh | 25 ------------
 4 files changed, 103 insertions(+), 26 deletions(-)
 create mode 100755 set-cross-compile.py
 delete mode 100755 set-cross-compile.sh

diff --git a/Changes.md b/Changes.md
index 2588730..a227839 100644
--- a/Changes.md
+++ b/Changes.md
@@ -1,3 +1,8 @@
+## 1.0.1
+
+- Fixed a bug where this action would attempt to use `cross` when compiling for an ARM Linux target
+  on an ARM Linux host.
+
 ## 1.0.0 - 2025-01-11
 
 The addition of caching is a significant behavior change for this action, so the version has been
diff --git a/action.yml b/action.yml
index cf4b3fd..16cf870 100644
--- a/action.yml
+++ b/action.yml
@@ -76,7 +76,7 @@ runs:
     - name: Determine whether we need to cross-compile
       id: determine-cross-compile
       shell: bash
-      run: set-cross-compile.sh ${{ inputs.target }}
+      run: set-cross-compile.py ${{ inputs.target }}
     - name: Install toolchain
       uses: dtolnay/rust-toolchain@master
       with:
diff --git a/set-cross-compile.py b/set-cross-compile.py
new file mode 100755
index 0000000..d0dfc5f
--- /dev/null
+++ b/set-cross-compile.py
@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+
+# Written mostly by Claude.ai based on my original bash script.
+
+import sys
+import platform
+import re
+import os
+from subprocess import run, PIPE, CalledProcessError
+
+
+def main() -> int:
+    """
+    Main function to determine cross-compilation requirements.
+
+    Returns:
+        Exit code (0 for success)
+    """
+    if len(sys.argv) < 2:
+        print("Error: Target architecture argument is required", file=sys.stderr)
+        return 1
+
+    target = sys.argv[1]
+    needs_cross = check_needs_cross(target)
+    write_github_output(needs_cross)
+
+    return 0
+
+
+def check_needs_cross(target: str) -> bool:
+    """
+    Determine if cross-compilation is needed based on system and target.
+
+    Args:
+        target: Target architecture string
+
+    Returns:
+        Boolean indicating if cross-compilation is needed
+    """
+    system_info = get_uname_info().lower()
+
+    # Check if we're on macOS or Windows
+    if any(os in system_info for os in ["darwin", "msys", "windows"]):
+        return False
+
+    target = target.lower()
+
+    # Check for x86_64 Linux targets on x86_64 Linux host
+    if (
+        re.search(r"x86_64.+linux-(?:gnu|musl)", target)
+        and "x86_64" in system_info
+        and "linux" in system_info
+    ):
+        return False
+
+    # Check if both host and target are ARM Linux. I'm assuming here that for things like
+    # "arm-linux-androideabi" or "armv7-unknown-linux-ohos" we'd still need cross.
+    if (
+        re.search(r"(?:aarch64|arm).+linux-(?:gnu|musl)", target)
+        and ("arm" in system_info or "aarch64" in system_info)
+        and "linux" in system_info
+    ):
+        return False
+
+    return True
+
+
+def get_uname_info() -> str:
+    """
+    Get system information using uname command.
+
+    Returns:
+        String containing system information
+    """
+    try:
+        result = run(["uname", "-a"], check=True, text=True, stdout=PIPE)
+        return result.stdout
+    except (CalledProcessError, FileNotFoundError):
+        # Fallback to platform.platform() if uname is not available
+        return platform.platform()
+
+
+def write_github_output(needs_cross: bool) -> None:
+    """
+    Write the needs-cross output to GITHUB_OUTPUT environment variable file.
+
+    Args:
+        needs_cross: Boolean indicating if cross-compilation is needed
+    """
+    github_output = os.getenv("GITHUB_OUTPUT")
+    if github_output:
+        with open(github_output, "a") as f:
+            f.write(f"needs-cross={str(needs_cross).lower()}\n")
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/set-cross-compile.sh b/set-cross-compile.sh
deleted file mode 100755
index a5bc987..0000000
--- a/set-cross-compile.sh
+++ /dev/null
@@ -1,25 +0,0 @@
-#!/bin/bash
-
-set -e
-set -x
-set -o pipefail
-
-TARGET="$1"
-
-# On macOS and Windows, we can cross-compile to all possible targets without
-# using cross.
-if uname -a | grep --quiet --extended-regexp -i "darwin|msys|windows"; then
-    echo "needs-cross=false" >>"$GITHUB_OUTPUT"
-    exit 0
-fi
-
-# On Linux, we should be able to cross-compile to i586 and i686, but in
-# practice this fails with some crates, notably openssl with the "vendored"
-# feature. This feature makes it compile openssl itself, which fails without
-# cross.
-if echo "$TARGET" | grep --quiet --extended-regexp -i 'x86_64.+linux-(gnu|musl)'; then
-    echo "needs-cross=false" >>"$GITHUB_OUTPUT"
-    exit 0
-fi
-
-echo "needs-cross=true" >>"$GITHUB_OUTPUT"