Relicense Sire's Python API from LGPLv3+ to MIT

.github/pull_request_template.md

@@ -6,7 +6,7 @@ This pull request fixes issue #?
 
 * I confirm that I have merged the latest version of `devel` into this branch before issuing this pull request (e.g. by running `git pull origin devel`): [y/n]
 * I confirm that I have added a changelog entry to the changelog (we will add a link to this PR as part of the review): [y/n]
-* I confirm that I have permission to release this code under the LGPLv3+ license: [y/n]
+* I confirm that I have permission to release this code under the MIT license (the Python API) or the LGPLv3+ license (everything else), as described in the `LICENSE` file: [y/n]
 
 ## If this introduces new functionality...
 
@@ -16,7 +16,7 @@ Changes proposed in this pull request:
 * I confirm that I have added a test for any new functionality in this pull request: [y/n]
 * I confirm that I have added documentation (e.g. a new tutorial page or detailed guide) for any new functionality in this pull request: [y/n]
 * I confirm that I have added a changelog entry to the changelog (we will add a link to this PR as part of the review): [y/n]
-* I confirm that I have permission to release this code under the LGPLv3+ license: [y/n]
+* I confirm that I have permission to release this code under the MIT license (the Python API) or the LGPLv3+ license (everything else), as described in the `LICENSE` file: [y/n]
 
 ## Suggested reviewers:
 @chryswoods, @lohedges

LICENSE

@@ -1,7 +1,41 @@
-Sire is licensed under the GNU Lesser General Public License, version 3
-or (at your option) any later version. The LGPL is a set of additional
+Sire is distributed under two licenses.
+
+The Python API is licensed under the MIT License. This covers the Python
+source in the src directory, plus the following files that implement the
+OpenMM layer used by the Python API:
+
+    wrapper/Convert/SireOpenMM/_perturbablemol.py
+    wrapper/Convert/SireOpenMM/_sommcontext.py
+
+Everything else, including the C++ libraries and their Python wrappers,
+is licensed under the GNU Lesser General Public License, version 3 or
+(at your option) any later version. The LGPL is a set of additional
 permissions on top of the GNU General Public License, version 3, so the
-full text of both licenses is included below.
+full text of both licenses is included below, after the MIT License.
+
+------------------------------------------------------------------------
+
+                              MIT License
+
+Copyright (c) The Sire contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
 
 ------------------------------------------------------------------------
 

README.rst

@@ -174,6 +174,26 @@ This is intended as a local development tweak only and shouldn't be committed,
 since ``actions/generate_recipe.py`` reads the ``[dependencies]`` section when
 generating the conda recipe, so the pin would also end up in our packages.
 
+License
+=======
+
+Sire is distributed under two licenses:
+
+* The Python API is licensed under the
+  `MIT License <https://opensource.org/license/mit>`__. This covers the
+  Python source in ``src/``, plus
+  ``wrapper/Convert/SireOpenMM/_perturbablemol.py`` and
+  ``wrapper/Convert/SireOpenMM/_sommcontext.py``. You are free to adapt,
+  extend, or include this code in your own projects, provided the copyright
+  and license notice is kept.
+* Everything else, including the C++ libraries and their Python wrappers, is
+  licensed under the
+  `GNU Lesser General Public License, version 3 or later <https://www.gnu.org/licenses/lgpl-3.0.en.html>`__
+  (LGPLv3+). You can use Sire as a library from software under any license,
+  but changes to these parts of Sire must be shared under the LGPL.
+
+See the `LICENSE <LICENSE>`__ file for the full terms.
+
 Support and Development
 =======================
 

actions/generate_recipe.py

@@ -401,7 +401,7 @@ def generate_recipe(data, features, git_remote, git_branch, git_version, git_num
     # About
     lines.append("about:")
     lines.append("  homepage: https://github.com/openbiosim/sire")
-    lines.append("  license: LGPL-3.0-or-later")
+    lines.append("  license: LGPL-3.0-or-later AND MIT")
     lines.append("  license_file: LICENSE")
     lines.append('  summary: "An advanced molecular modelling framework."')
     lines.append("  repository: https://github.com/openbiosim/sire")

doc/source/acknowledgements.rst

@@ -62,9 +62,10 @@ which can be found below. The software will be installed automatically
 as part of the installing the :mod:`sire` conda package, so you shouldn't
 have to do anything yourself.
 
-:mod:`sire` is itself distributed under the terms of the GNU Lesser
-General Public License, version 3 or (at your option) any later version
-(LGPLv3+). Some optional dependencies are licensed differently, e.g.
+:mod:`sire` itself is distributed under the terms of the MIT License (the
+Python API) and the GNU Lesser General Public License, version 3 or (at your
+option) any later version (everything else). See the :doc:`license <license>`
+page for details. Some optional dependencies are licensed differently, e.g.
 `emle-engine <https://github.com/chemle/emle-engine>`__ (GPLv2), which is
 conditionally imported for QM/MM calculations if it is installed. These are
 not distributed with :mod:`sire` and are used under their own license terms.

doc/source/changelog.rst

@@ -121,6 +121,10 @@ organisation on `GitHub <https://github.com/openbiosim/sire>`__.
 
 * Fixed reading a DCD frame reading the coordinates, space and time from the file twice.
 
+* Relicensed the Python API, i.e. the Python source in ``src`` and the two Python files in
+  ``wrapper/Convert/SireOpenMM`` that implement its OpenMM layer, from the LGPLv3+ to the MIT
+  License. The rest of :mod:`sire` remains LGPLv3+.
+
 `2026.2.0 <https://github.com/openbiosim/sire/compare/2026.1.0...2026.2.0>`__ - September 2026
 ----------------------------------------------------------------------------------------------
 

doc/source/index.rst

@@ -105,6 +105,14 @@ Changelog
 
    changelog
 
+License
+=======
+
+.. toctree::
+   :maxdepth: 1
+
+   license
+
 Acknowledgements
 ================
 .. toctree::

doc/source/license.rst

@@ -0,0 +1,24 @@
+=======
+License
+=======
+
+:mod:`sire` is distributed under two licenses:
+
+* The Python API is licensed under the
+  `MIT License <https://opensource.org/license/mit>`__. This covers the
+  Python source in ``src/``, plus
+  ``wrapper/Convert/SireOpenMM/_perturbablemol.py`` and
+  ``wrapper/Convert/SireOpenMM/_sommcontext.py``. You are free to adapt,
+  extend, or include this code in your own projects, provided the copyright
+  and license notice is kept.
+* Everything else, including the C++ libraries and their Python wrappers, is
+  licensed under the
+  `GNU Lesser General Public License, version 3 or later <https://www.gnu.org/licenses/lgpl-3.0.en.html>`__
+  (LGPLv3+). You can use :mod:`sire` as a library from software under any
+  license, but changes to these parts of :mod:`sire` must be shared under the
+  LGPL.
+
+The full terms are in the
+`LICENSE <https://github.com/OpenBioSim/sire/blob/main/LICENSE>`__ file.
+Details of the licenses of the third party software that :mod:`sire` depends
+on can be found in the :doc:`acknowledgements <acknowledgements>`.

recipes/sire/LICENSE

@@ -1,7 +1,41 @@
-Sire is licensed under the GNU Lesser General Public License, version 3
-or (at your option) any later version. The LGPL is a set of additional
+Sire is distributed under two licenses.
+
+The Python API is licensed under the MIT License. This covers the Python
+source in the src directory, plus the following files that implement the
+OpenMM layer used by the Python API:
+
+    wrapper/Convert/SireOpenMM/_perturbablemol.py
+    wrapper/Convert/SireOpenMM/_sommcontext.py
+
+Everything else, including the C++ libraries and their Python wrappers,
+is licensed under the GNU Lesser General Public License, version 3 or
+(at your option) any later version. The LGPL is a set of additional
 permissions on top of the GNU General Public License, version 3, so the
-full text of both licenses is included below.
+full text of both licenses is included below, after the MIT License.
+
+------------------------------------------------------------------------
+
+                              MIT License
+
+Copyright (c) The Sire contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
 
 ------------------------------------------------------------------------
 

setup.py

@@ -756,7 +756,7 @@ def install(ncores: int = 1, npycores: int = 1):
                     "build_number": 0,
                     "channel": "local",
                     "size": 0,
-                    "license": "LGPL-3.0-or-later",
+                    "license": "LGPL-3.0-or-later AND MIT",
                     "subdir": platform_string,
                 }
                 metadata_file = os.path.join(

src/sire/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 from . import config
 
 import os as _os

src/sire/_colname.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["colname", "colnames"]
 
 _col_funcs = None

src/sire/_lazy_import.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 """
 A minimal, standard-library-only replacement for the third-party
 `lazy_import` package (GPLv3), used to defer importing submodules until

src/sire/_load.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 from typing import Union as _Union
 from typing import List as _List
 

src/sire/_match.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["match_atoms"]
 
 

src/sire/_measure.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["measure", "minimum_distance"]
 
 

src/sire/_parallel.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "get_max_num_threads",
     "set_default_num_threads",

src/sire/_pythonize.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["use_old_api", "use_new_api", "use_mixed_api"]
 
 

src/sire/analysis/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = []
 
 # Need to import the module to pythonize it

src/sire/base/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "create_map",
     "wrap",

src/sire/base/_pagecache.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["PageCache"]
 
 from ..legacy.Base import PageCache
@@ -24,7 +26,6 @@ def __fetch__(obj):
     """
     Fetch the object from the cache and return it
     """
-    from ..legacy.Qt import QByteArray
     from pickle import loads
 
     data = obj.__orig__fetch__()

src/sire/base/_progressbar.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["ProgressBar"]
 
 from ..legacy.Base import ProgressBar as _ProgressBar

src/sire/cas/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["Expression", "lam", "Symbol", "x", "y", "LambdaSchedule"]
 
 from ..legacy import CAS as _CAS

src/sire/cluster/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = []
 
 # Need to import so it is pythonized

src/sire/config/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "binary_directory",
     "include_directory",

src/sire/convert/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "biosimspace_to_sire",
     "gemmi_to_sire",

src/sire/convert/openmm/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "LambdaLever",
     "OpenMMMetaData",

src/sire/convert/openmm/_pme.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["tune_pme"]
 
 

src/sire/error/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "disable_backtrace_exceptions",
     "enable_backtrace_exceptions",

src/sire/ff/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = []
 
 # Need to import so the module is pythonized

src/sire/id/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["CaseInsensitive", "CaseSensitive"]
 
 from ..legacy import ID as _ID

src/sire/io/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = ["get_coords_array", "resolve_path"]
 
 from ..legacy import IO as _IO

src/sire/io/parser/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "DCD",
     "G87",

src/sire/maths/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "align",
     "create_quaternion",

src/sire/maths/_sphere.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 from ..legacy.Maths import Sphere as _Sphere
 
 

src/sire/maths/_vector.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 from ..legacy.Maths import Vector as _Vector
 
 

src/sire/mm/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "AmberBond",
     "AmberAngle",

src/sire/mol/__init__.py

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: MIT
+
 __all__ = [
     "get_alignment",
     "is_water",