Compat fix for older numpy versions (#517)

* Compat fix for older numpy versions

* Adding test environment for old numpy versions

* Fixing lint

---------

Co-authored-by: Dan Foreman-Mackey <dfm@dfm.io>

Author: MuellerSeb

.github/workflows/tests.yml

@@ -49,12 +49,17 @@ jobs:
           COVERALLS_PARALLEL: true
           COVERALLS_FLAG_NAME: ${{ matrix.python-version }}-${{ matrix.os }}
 
-  leading_edge:
+  numpy_edge:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
         python-version: ["3.12"]
+        numpy-version: ["numpy>=2.0.0rc1"]
         os: ["ubuntu-latest"]
+        include:
+          - python-version: "3.9"
+            numpy-version: "numpy<1.25"
+            os: "ubuntu-latest"
 
     steps:
       - name: Checkout
@@ -68,7 +73,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install -U pip
-          python -m pip install pip install pytest "numpy>=2.0.0rc1"
+          python -m pip install pip install pytest "${{ matrix.numpy-version }}"
           python -m pip install -e.
       - name: Run tests
         run: pytest

src/emcee/ensemble.py

@@ -21,6 +21,13 @@
     # for py2.7, will be an Exception in 3.8
     from collections import Iterable
 
+try:
+    # Try to import from numpy.exceptions (available in NumPy 1.25 and later)
+    from numpy.exceptions import VisibleDeprecationWarning
+except ImportError:
+    # Fallback to the top-level numpy import (for older versions)
+    from numpy import VisibleDeprecationWarning
+
 
 class EnsembleSampler(object):
     """An ensemble MCMC sampler
@@ -511,7 +518,7 @@ def compute_log_prob(self, coords):
                 try:
                     with warnings.catch_warnings(record=True):
                         warnings.simplefilter(
-                            "error", np.exceptions.VisibleDeprecationWarning
+                            "error", VisibleDeprecationWarning
                         )
                         try:
                             dt = np.atleast_1d(blob[0]).dtype