From e95466774e1b3cfe4312710624ecfd026d6e3c7a Mon Sep 17 00:00:00 2001
From: Sean Law <seanmylaw@gmail.com>
Date: Wed, 21 Jan 2026 00:24:14 -0500
Subject: [PATCH] Fixed #1116 Avoid Import Fastmath Functions

---
 pyproject.toml         |  2 ++
 stumpy/__init__.py     | 36 +++++++++++++++++++++++-------------
 tests/test_fastmath.py | 16 +++++++++++++++-
 3 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 5fc40c465..2a2d5dfbb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -112,3 +112,5 @@ tbb = ">=2019.5"
 tests = "./test.sh"
 coverage = "./test.sh coverage"
 docs = "cd docs && ./setup.sh"
+black = 'black --exclude=".*\.ipynb" --extend-exclude=".venv|.pixi" --diff ./'
+isort = 'isort --profile black --skip .venv --skip .pixi ./'
diff --git a/stumpy/__init__.py b/stumpy/__init__.py
index 870912b15..5df46ff8c 100644
--- a/stumpy/__init__.py
+++ b/stumpy/__init__.py
@@ -1,9 +1,9 @@
-import importlib
+import ast
 import os.path
+import pathlib
 from importlib.metadata import distribution
 from site import getsitepackages
 
-import numba
 from numba import cuda
 
 from . import cache, config
@@ -38,14 +38,27 @@
 # Get the default fastmath flags for all njit functions
 # and update the _STUMPY_DEFAULTS dictionary
 
-if not numba.config.DISABLE_JIT:  # pragma: no cover
-    njit_funcs = cache.get_njit_funcs()
-    for module_name, func_name in njit_funcs:
-        module = importlib.import_module(f".{module_name}", package="stumpy")
-        func = getattr(module, func_name)
-        key = module_name + "." + func_name  # e.g., core._mass
-        key = "STUMPY_FASTMATH_" + key.upper()  # e.g., STUMPY_FASTHMATH_CORE._MASS
-        config._STUMPY_DEFAULTS[key] = func.targetoptions["fastmath"]
+
+def _get_fastmath_value(module_name, func_name):  # pragma: no cover
+    fname = module_name + ".py"
+    fname = pathlib.Path(__file__).parent / fname
+    with open(fname, "r", encoding="utf-8") as f:
+        src = f.read()
+        tree = ast.parse(src)
+        for node in ast.walk(tree):
+            if isinstance(node, ast.FunctionDef) and node.name == func_name:
+                for dec in node.decorator_list:
+                    for kw in dec.keywords:
+                        if kw.arg == "fastmath":
+                            fastmath_flag = ast.get_source_segment(src, kw.value)
+                            return eval(fastmath_flag)
+
+
+njit_funcs = cache.get_njit_funcs()
+for module_name, func_name in njit_funcs:
+    key = module_name + "." + func_name  # e.g., core._mass
+    key = "STUMPY_FASTMATH_" + key.upper()  # e.g., STUMPY_FASTHMATH_CORE._MASS
+    config._STUMPY_DEFAULTS[key] = _get_fastmath_value(module_name, func_name)
 
 if cuda.is_available():
     from .gpu_aamp import gpu_aamp  # noqa: F401
@@ -72,9 +85,6 @@
     core._gpu_searchsorted_left = core._gpu_searchsorted_left_driver_not_found
     core._gpu_searchsorted_right = core._gpu_searchsorted_right_driver_not_found
 
-    import ast
-    import pathlib
-
     # Fix GPU-STUMP Docs
     gpu_stump.__doc__ = ""
     filepath = pathlib.Path(__file__).parent / "gpu_stump.py"
diff --git a/tests/test_fastmath.py b/tests/test_fastmath.py
index a16bb6898..92366069f 100644
--- a/tests/test_fastmath.py
+++ b/tests/test_fastmath.py
@@ -1,7 +1,10 @@
+import importlib
+
 import numba
 import numpy as np
+import pytest
 
-from stumpy import cache, fastmath
+from stumpy import _get_fastmath_value, cache, fastmath
 
 
 def test_set():
@@ -50,3 +53,14 @@ def test_reset():
         assert np.isnan(fastmath._add_assoc(0.0, np.inf))
     else:  # pragma: no cover
         assert fastmath._add_assoc(0.0, np.inf) == 0.0
+
+
+@pytest.mark.skipif(numba.config.DISABLE_JIT, reason="JIT Disabled")
+def test_get_fastmath_value():  # pragma: no cover
+    njit_funcs = cache.get_njit_funcs()
+    for module_name, func_name in njit_funcs:
+        module = importlib.import_module(f".{module_name}", package="stumpy")
+        func = getattr(module, func_name)
+        ref = func.targetoptions["fastmath"]
+        cmp = _get_fastmath_value(module_name, func_name)
+        assert ref == cmp