Remove support for dill as a serialization backend.

doc/install.rst

@@ -17,8 +17,6 @@ pygmo has the following **mandatory** runtime dependencies:
 Additionally, pygmo has the following **optional** runtime
 dependencies:
 
-* `dill <https://dill.readthedocs.io>`__, which can be used as an
-  alternative serialization backend,
 * `Matplotlib <https://matplotlib.org/>`__, which is used by a few
   plotting utilities,
 * `NetworkX <https://networkx.github.io/>`__, which is used for

pygmo/__init__.py

@@ -746,8 +746,7 @@ def set_serialization_backend(name):
     The valid backends are:
 
     * ``'pickle'`` (i.e., the standard Python :mod:`pickle` module),
-    * ``'cloudpickle'``,
-    * ``'dill'`` (from the `dill <https://pypi.org/project/dill/>`__ library).
+    * ``'cloudpickle'``.
 
     .. warning::
 
@@ -760,8 +759,7 @@ def set_serialization_backend(name):
 
     Raises:
         TypeError: if *name* is not a :class:`str`
-        ValueError: if *name* is not one of ``['pickle', 'cloudpickle', 'dill']``
-        ImportError: if *name* is ``'dill'`` but the dill module is not installed
+        ValueError: if *name* is not one of ``['pickle', 'cloudpickle']``
 
     """
     if not isinstance(name, str):
@@ -777,18 +775,9 @@ def set_serialization_backend(name):
         _serialization_backend = pickle
     elif name == "cloudpickle":
         _serialization_backend = _cloudpickle
-    elif name == "dill":
-        try:
-            import dill
-
-            _serialization_backend = dill
-        except ImportError:
-            raise ImportError(
-                "The 'dill' serialization backend was specified, but the dill module is not installed."
-            )
     else:
         raise ValueError(
-            "The serialization backend '{}' is not valid. The valid backends are: ['pickle', 'cloudpickle', 'dill']".format(
+            "The serialization backend '{}' is not valid. The valid backends are: ['pickle', 'cloudpickle']".format(
                 name
             )
         )

pygmo/_island_test.py

@@ -501,17 +501,8 @@ def run_basic_tests(self):
         from . import mp_island
         from copy import copy, deepcopy
 
-        has_dill = False
-        try:
-            import dill
+        from pickle import dumps, loads
 
-            has_dill = True
-        except ImportError:
-            pass
-        if has_dill:
-            from dill import dumps, loads
-        else:
-            from pickle import dumps, loads
         # Try shutting down a few times, to confirm that the second
         # and third shutdowns don't do anything.
         mp_island.shutdown_pool()

pygmo/_py_islands.py

@@ -12,17 +12,8 @@
 def _evolve_func_mp_pool(ser_algo_pop):
     # The evolve function that is actually run from the separate processes
     # in mp_island (when using the pool).
-    has_dill = False
-    try:
-        import dill
-
-        has_dill = True
-    except ImportError:
-        pass
-    if has_dill:
-        from dill import dumps, loads
-    else:
-        from pickle import dumps, loads
+    from pickle import dumps, loads
+
     algo, pop = loads(ser_algo_pop)
     new_pop = algo.evolve(pop)
     return dumps((algo, new_pop))
@@ -44,17 +35,8 @@ def _evolve_func_mp_pipe(conn, ser_algo_pop):
     # of a child process happens in a separate thread and Python disallows messing
     # with signal handlers from a thread different from the main one :(
     with _temp_disable_sigint():
-        has_dill = False
-        try:
-            import dill
+        from pickle import dumps, loads
 
-            has_dill = True
-        except ImportError:
-            pass
-        if has_dill:
-            from dill import dumps, loads
-        else:
-            from pickle import dumps, loads
         try:
             algo, pop = loads(ser_algo_pop)
             new_pop = algo.evolve(pop)
@@ -227,17 +209,8 @@ def run_evolve(self, algo, pop):
         # that if there are serialization errors, we catch them early here rather
         # than failing in the bootstrap phase of the remote process, which
         # can lead to hangups.
-        has_dill = False
-        try:
-            import dill
+        from pickle import dumps, loads
 
-            has_dill = True
-        except ImportError:
-            pass
-        if has_dill:
-            from dill import dumps, loads
-        else:
-            from pickle import dumps, loads
         ser_algo_pop = dumps((algo, pop))
 
         if self._use_pool:
@@ -470,17 +443,8 @@ def shutdown_pool():
 def _evolve_func_ipy(ser_algo_pop):
     # The evolve function that is actually run from the separate processes
     # in ipyparallel_island.
-    has_dill = False
-    try:
-        import dill
-
-        has_dill = True
-    except ImportError:
-        pass
-    if has_dill:
-        from dill import dumps, loads
-    else:
-        from pickle import dumps, loads
+    from pickle import dumps, loads
+
     algo, pop = loads(ser_algo_pop)
     new_pop = algo.evolve(pop)
     return dumps((algo, new_pop))
@@ -613,17 +577,7 @@ def run_evolve(self, algo, pop):
         # serialization errors early.
         from ._ipyparallel_utils import _make_ipyparallel_view
 
-        has_dill = False
-        try:
-            import dill
-
-            has_dill = True
-        except ImportError:
-            pass
-        if has_dill:
-            from dill import dumps, loads
-        else:
-            from pickle import dumps, loads
+        from pickle import dumps, loads
 
         ser_algo_pop = dumps((algo, pop))
         with ipyparallel_island._view_lock:

pygmo/test.py

@@ -69,14 +69,6 @@ def run_s11n_test(self):
         from . import set_serialization_backend as ssb, get_serialization_backend as gsb
         from . import problem, island, de
 
-        has_dill = False
-        try:
-            import dill
-
-            has_dill = True
-        except ImportError:
-            pass
-
         # Default s11n backend.
         self.assertTrue(gsb() == clpickle)
 
@@ -93,19 +85,10 @@ def run_s11n_test(self):
             ssb("hello")
         err = cm.exception
         self.assertEqual(
-            "The serialization backend 'hello' is not valid. The valid backends are: ['pickle', 'cloudpickle', 'dill']",
+            "The serialization backend 'hello' is not valid. The valid backends are: ['pickle', 'cloudpickle']",
             str(err),
         )
 
-        if not has_dill:
-            with self.assertRaises(ImportError) as cm:
-                ssb("dill")
-            err = cm.exception
-            self.assertEqual(
-                "The 'dill' serialization backend was specified, but the dill module is not installed.",
-                str(err),
-            )
-
         ssb("pickle")
         self.assertTrue(gsb() == pickle)
 
@@ -115,16 +98,6 @@ def run_s11n_test(self):
         isl = island(prob=p, algo=de(gen=500), size=20)
         self.assertEqual(str(pickle.loads(pickle.dumps(isl))), str(isl))
 
-        # Try with dill as well, if available.
-        if has_dill:
-            ssb("dill")
-            self.assertTrue(gsb() == dill)
-
-            p = problem(_prob())
-            self.assertEqual(str(dill.loads(dill.dumps(p))), str(p))
-            isl = island(prob=p, algo=de(gen=500), size=20)
-            self.assertEqual(str(dill.loads(dill.dumps(isl))), str(isl))
-
         # Reset to cloudpickle before exiting.
         ssb("cloudpickle")
         self.assertTrue(gsb() == clpickle)
@@ -1495,17 +1468,8 @@ def run_pickle_tests(self):
             migrant_handling,
         )
 
-        has_dill = False
-        try:
-            import dill
+        from pickle import dumps, loads
 
-            has_dill = True
-        except ImportError:
-            pass
-        if has_dill:
-            from dill import dumps, loads
-        else:
-            from pickle import dumps, loads
         a = archipelago(5, algo=de(), prob=rosenbrock(), pop_size=10)
         self.assertEqual(repr(a), repr(loads(dumps(a))))
         a = archipelago(5, algo=de(), prob=_prob(), pop_size=10, udi=mp_island())

tools/circleci_bionic_conda_pagmo_head_310.sh

@@ -16,7 +16,7 @@ export PATH="$HOME/miniconda/bin:$PATH"
 bash miniconda.sh -b -p $HOME/miniconda
 conda config --add channels conda-forge
 conda config --set channel_priority strict
-conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.10 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 sphinx=4.5.0 myst-nb sphinx-book-theme scipy
+conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.10 numpy cloudpickle networkx numba pybind11 sphinx=4.5.0 myst-nb sphinx-book-theme scipy
 source activate $deps_dir
 
 # Install pagmo.

tools/circleci_bionic_conda_pagmo_head_38.sh

@@ -16,7 +16,7 @@ export PATH="$HOME/miniconda/bin:$PATH"
 bash miniconda.sh -b -p $HOME/miniconda
 conda config --add channels conda-forge
 conda config --set channel_priority strict
-conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.8 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 scipy
+conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.8 numpy cloudpickle networkx numba pybind11 scipy
 source activate $deps_dir
 
 # Install pagmo.

tools/circleci_bionic_conda_pagmo_head_39.sh

@@ -16,7 +16,7 @@ export PATH="$HOME/miniconda/bin:$PATH"
 bash miniconda.sh -b -p $HOME/miniconda
 conda config --add channels conda-forge
 conda config --set channel_priority strict
-conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.9 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 scipy
+conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.9 numpy cloudpickle networkx numba pybind11 scipy
 source activate $deps_dir
 
 # Install pagmo.

tools/circleci_ubuntu_arm64.sh

@@ -14,7 +14,7 @@ wget https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge
 export deps_dir=$HOME/local
 export PATH="$HOME/miniconda/bin:$PATH"
 bash miniconda.sh -b -p $HOME/miniconda
-conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt boost-cpp tbb tbb-devel python=3.8 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 scipy
+conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt boost-cpp tbb tbb-devel python=3.8 numpy cloudpickle networkx numba pybind11 scipy
 source activate $deps_dir
 
 # Install pagmo.

tools/gha_deploydocs.sh

@@ -17,7 +17,7 @@ bash miniconda.sh -b -p $HOME/miniconda
 conda config --add channels conda-forge
 conda config --set channel_priority strict
 conda install mamba
-mamba create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.10 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 sphinx=4.5.0 myst-nb sphinx-book-theme scipy
+mamba create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.10 numpy cloudpickle networkx numba pybind11 sphinx=4.5.0 myst-nb sphinx-book-theme scipy
 source activate $deps_dir
 
 # Install pagmo.

tools/gha_macos-10.15-py310.sh

@@ -13,7 +13,7 @@ export PATH="$HOME/miniconda/bin:$PATH"
 bash miniconda.sh -b -p $HOME/miniconda
 conda config --add channels conda-forge
 conda config --set channel_priority strict
-conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.10 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 sphinx myst-nb sphinx-book-theme scipy
+conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt ipopt boost-cpp tbb tbb-devel python=3.10 numpy cloudpickle networkx numba pybind11 sphinx myst-nb sphinx-book-theme scipy
 source activate $deps_dir
 
 # Install pagmo.

tools/gha_manylinux.sh

@@ -49,7 +49,7 @@ fi
 # Python mandatory deps.
 /opt/python/${PYTHON_DIR}/bin/pip install cloudpickle numpy
 # Python optional deps.
-/opt/python/${PYTHON_DIR}/bin/pip install dill==0.3.5.1 networkx ipyparallel scipy
+/opt/python/${PYTHON_DIR}/bin/pip install networkx ipyparallel scipy
 
 # In the pagmo2/manylinux228_x86_64_with_deps:latest image in dockerhub
 # the working directory is /root/install, we will install pagmo there

tools/gha_windows.ps1

@@ -2,7 +2,7 @@
 # Powershell script
 # Install conda environment
 conda config --set always_yes yes
-conda create --name pygmo cmake eigen nlopt ipopt boost-cpp tbb tbb-devel numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 scipy
+conda create --name pygmo cmake eigen nlopt ipopt boost-cpp tbb tbb-devel numpy cloudpickle networkx numba pybind11 scipy
 conda activate pygmo
 
 # Install pagmo.

tools/travis_ubuntu_ppc64.sh

@@ -14,7 +14,7 @@ wget https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge
 export deps_dir=$HOME/local
 export PATH="$HOME/miniconda/bin:$PATH"
 bash miniconda.sh -b -p $HOME/miniconda
-conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt boost-cpp tbb tbb-devel python=3.8 numpy cloudpickle networkx dill=0.3.5.1 numba pybind11 scipy
+conda create -y -q -p $deps_dir c-compiler cxx-compiler cmake eigen nlopt boost-cpp tbb tbb-devel python=3.8 numpy cloudpickle networkx numba pybind11 scipy
 source activate $deps_dir
 
 # Install pagmo.