Canonicalize the path returned by current_binary_dir()

mlx/backend/common/utils.cpp

@@ -12,7 +12,10 @@ std::filesystem::path current_binary_dir() {
     if (!dladdr(reinterpret_cast<void*>(&current_binary_dir), &info)) {
       throw std::runtime_error("Unable to get current binary dir.");
     }
-    return std::filesystem::path(info.dli_fname).parent_path();
+    // dli_fname is the path the binary was loaded by, which may be relative,
+    // contain ".." or go through a symlink. Callers append relative paths to
+    // the result and check them for existence, so it has to be resolved.
+    return std::filesystem::weakly_canonical(info.dli_fname).parent_path();
   }();
   return binary_dir;
 }

tests/utils_tests.cpp

@@ -2,10 +2,17 @@
 
 #include "doctest/doctest.h"
 
+#include "mlx/backend/common/utils.h"
 #include "mlx/mlx.h"
 
 using namespace mlx::core;
 
+TEST_CASE("test current binary dir is resolved") {
+  auto dir = current_binary_dir();
+  CHECK(dir.is_absolute());
+  CHECK_EQ(dir, std::filesystem::weakly_canonical(dir));
+}
+
 TEST_CASE("test type promotion") {
   for (auto t : {bool_, uint32, int32, int64, float32}) {
     auto a = array(0, t);