FIX check symbols to better identify supported libraries

CHANGES.md

@@ -1,3 +1,11 @@
+3.2.1 (TBD)
+===========
+
+- Fixed a bug where an unsupported library would be detected because it shares a common
+  prefix with one of the supported libraries. Now the symbols are also checked to
+  identify the supported libraries.
+  https://github.com/joblib/threadpoolctl/pull/151
+
 3.2.0 (2023-07-13)
 ==================
 

continuous_integration/install_with_blis.sh

@@ -35,6 +35,7 @@ popd
 # build & install numpy
 git clone https://github.com/numpy/numpy.git
 pushd numpy
+git checkout v1.26.0  # pin numpy < 2 for now
 git submodule update --init
 echo "[blis]
 libraries = blis

tests/_pyMylib/__init__.py

@@ -19,6 +19,14 @@ class MyThreadedLibController(LibController):
     # instance.
     filename_prefixes = ("my_threaded_lib",)
 
+    # (Optional) Symbols that the linked library is expected to expose. It is used along
+    # with the `filename_prefixes` to make sure that the correct library is identified.
+    check_symbols = (
+        "mylib_get_num_threads",
+        "mylib_set_num_threads",
+        "mylib_get_version",
+    )
+
     def get_num_threads(self):
         # This function should return the current maximum number of threads,
         # which is reported as "num_threads" by `ThreadpoolController.info`.

threadpoolctl.py

@@ -157,7 +157,18 @@ class OpenBLASController(LibController):
     user_api = "blas"
     internal_api = "openblas"
     filename_prefixes = ("libopenblas", "libblas")
-    check_symbols = ("openblas_get_num_threads", "openblas_get_num_threads64_")
+    check_symbols = (
+        "openblas_get_num_threads",
+        "openblas_get_num_threads64_",
+        "openblas_set_num_threads",
+        "openblas_set_num_threads64_",
+        "openblas_get_config",
+        "openblas_get_config64_",
+        "openblas_get_parallel",
+        "openblas_get_parallel64_",
+        "openblas_get_corename",
+        "openblas_get_corename64_",
+    )
 
     def set_additional_attributes(self):
         self.threading_layer = self._get_threading_layer()
@@ -237,7 +248,15 @@ class BLISController(LibController):
     user_api = "blas"
     internal_api = "blis"
     filename_prefixes = ("libblis", "libblas")
-    check_symbols = ("bli_thread_get_num_threads",)
+    check_symbols = (
+        "bli_thread_get_num_threads",
+        "bli_thread_set_num_threads",
+        "bli_info_get_version_str",
+        "bli_info_get_enable_openmp",
+        "bli_info_get_enable_pthreads",
+        "bli_arch_query_id",
+        "bli_arch_string",
+    )
 
     def set_additional_attributes(self):
         self.threading_layer = self._get_threading_layer()
@@ -266,9 +285,9 @@ def get_version(self):
 
     def _get_threading_layer(self):
         """Return the threading layer of BLIS"""
-        if self.dynlib.bli_info_get_enable_openmp():
+        if getattr(self.dynlib, "bli_info_get_enable_openmp", lambda: False)():
             return "openmp"
-        elif self.dynlib.bli_info_get_enable_pthreads():
+        elif getattr(self.dynlib, "bli_info_get_enable_pthreads", lambda: False)():
             return "pthreads"
         return "disabled"
 
@@ -292,7 +311,12 @@ class MKLController(LibController):
     user_api = "blas"
     internal_api = "mkl"
     filename_prefixes = ("libmkl_rt", "mkl_rt", "libblas")
-    check_symbols = ("MKL_Get_Max_Threads",)
+    check_symbols = (
+        "MKL_Get_Max_Threads",
+        "MKL_Set_Num_Threads",
+        "MKL_Get_Version_String",
+        "MKL_Set_Threading_Layer",
+    )
 
     def set_additional_attributes(self):
         self.threading_layer = self._get_threading_layer()
@@ -343,6 +367,10 @@ class OpenMPController(LibController):
     user_api = "openmp"
     internal_api = "openmp"
     filename_prefixes = ("libiomp", "libgomp", "libomp", "vcomp")
+    check_symbols = (
+        "omp_get_max_threads",
+        "omp_get_num_threads",
+    )
 
     def get_num_threads(self):
         get_func = getattr(self.dynlib, "omp_get_max_threads", lambda: None)
@@ -978,11 +1006,17 @@ def _make_controller_from_path(self, filepath):
                     # duplicate entry in threadpool_info.
                     continue
 
-            # filename matches a prefix. Create and store the library
+            # filename matches a prefix. Now we check if the library has the symbols we
+            # are looking for. If none of the symbols exists, it's very likely not the
+            # expected library (e.g. a library having a common prefix with one of the
+            # our supported libraries). Otherwise, create and store the library
             # controller.
-
             lib_controller = controller_class(filepath=filepath, prefix=prefix)
-            self.lib_controllers.append(lib_controller)
+            if not hasattr(controller_class, "check_symbols") or any(
+                hasattr(lib_controller.dynlib, func)
+                for func in controller_class.check_symbols
+            ):
+                self.lib_controllers.append(lib_controller)
 
     def _check_prefix(self, library_basename, filename_prefixes):
         """Return the prefix library_basename starts with