Retry the musl build when the glibc build does not load

Author: iacobdaniel

aikido_zen/helpers/zen_internals.py

@@ -59,7 +59,16 @@ def _load():
     try:
         return ctypes.CDLL(binary_path), None
     except OSError as e:
-        return None, f"Failed to load the zen-internals library for {_TARGET}: {e}"
+        error = e
+    # A musl Python built without HOST_GNU_TYPE picks the glibc build, which musl
+    # cannot load.
+    musl_path = binary_path.replace("-gnu.so", "-musl.so")
+    if musl_path != binary_path and os.path.exists(musl_path):
+        try:
+            return ctypes.CDLL(musl_path), None
+        except OSError:
+            pass
+    return None, f"Failed to load the zen-internals library for {_TARGET}: {error}"
 
 
 def _warn_unavailable(consequence, function_name):

aikido_zen/helpers/zen_internals_test.py

@@ -1,5 +1,6 @@
 import ctypes
 import os
+import shutil
 
 import pytest
 
@@ -60,6 +61,23 @@ def test_load_returns_none_when_library_fails_to_load(monkeypatch):
     assert "Failed to load the zen-internals library" in error
 
 
+def test_load_falls_back_to_the_musl_build_when_the_glibc_build_fails(
+    monkeypatch, tmp_path
+):
+    gnu_path = tmp_path / "libzen_internals_x86_64-unknown-linux-gnu.so"
+    gnu_path.write_text("not a library")
+    shutil.copy(
+        zen_internals._binary_path(), tmp_path / gnu_path.name.replace("-gnu", "-musl")
+    )
+    monkeypatch.setattr(
+        "aikido_zen.helpers.zen_internals._binary_path", lambda: str(gnu_path)
+    )
+
+    internals_lib, error = zen_internals._load()
+    assert internals_lib is not None
+    assert error is None
+
+
 def test_bind_returns_none_when_library_is_not_loaded():
     assert zen_internals._bind(None, "detect_sql_injection", [], ctypes.c_int) is None