Fix libpath logic for Windows (dmlc#9687)

Author: hcho3

python-package/packager/nativelib.py

@@ -132,16 +132,28 @@ def locate_or_build_libxgboost(
 
     if build_config.use_system_libxgboost:
         # Find libxgboost from system prefix
-        sys_base_prefix = pathlib.Path(sys.base_prefix).absolute().resolve()
-        libxgboost_sys = sys_base_prefix / "lib" / _lib_name()
-        if not libxgboost_sys.exists():
-            raise RuntimeError(
-                f"use_system_libxgboost was specified but {_lib_name()} is "
-                f"not found in {libxgboost_sys.parent}"
-            )
-
-        logger.info("Using system XGBoost: %s", str(libxgboost_sys))
-        return libxgboost_sys
+        sys_prefix = pathlib.Path(sys.prefix)
+        sys_prefix_candidates = [
+            sys_prefix / "lib",
+            # Paths possibly used on Windows
+            sys_prefix / "bin",
+            sys_prefix / "Library",
+            sys_prefix / "Library" / "bin",
+            sys_prefix / "Library" / "lib",
+        ]
+        sys_prefix_candidates = [
+            p.expanduser().resolve() for p in sys_prefix_candidates
+        ]
+        for candidate_dir in sys_prefix_candidates:
+            libtreelite_sys = candidate_dir / _lib_name()
+            if libtreelite_sys.exists():
+                logger.info("Using system XGBoost: %s", str(libtreelite_sys))
+                return libtreelite_sys
+        raise RuntimeError(
+            f"use_system_libxgboost was specified but {_lib_name()} is "
+            f"not found. Paths searched (in order): \n"
+            + "\n".join([f"* {str(p)}" for p in sys_prefix_candidates])
+        )
 
     libxgboost = locate_local_libxgboost(toplevel_dir, logger=logger)
     if libxgboost is not None:

python-package/xgboost/libpath.py

@@ -31,16 +31,15 @@ def find_lib_path() -> List[str]:
     ]
 
     if sys.platform == "win32":
-        if platform.architecture()[0] == "64bit":
-            dll_path.append(os.path.join(curr_path, "../../windows/x64/Release/"))
-            # hack for pip installation when copy all parent source
-            # directory here
-            dll_path.append(os.path.join(curr_path, "./windows/x64/Release/"))
-        else:
-            dll_path.append(os.path.join(curr_path, "../../windows/Release/"))
-            # hack for pip installation when copy all parent source
-            # directory here
-            dll_path.append(os.path.join(curr_path, "./windows/Release/"))
+        # On Windows, Conda may install libs in different paths
+        dll_path.extend(
+            [
+                os.path.join(sys.prefix, "bin"),
+                os.path.join(sys.prefix, "Library"),
+                os.path.join(sys.prefix, "Library", "bin"),
+                os.path.join(sys.prefix, "Library", "lib"),
+            ]
+        )
         dll_path = [os.path.join(p, "xgboost.dll") for p in dll_path]
     elif sys.platform.startswith(("linux", "freebsd", "emscripten")):
         dll_path = [os.path.join(p, "libxgboost.so") for p in dll_path]