build: clean up setuptools code

Author: MilesCranmer

Apptainer.def

@@ -20,7 +20,7 @@ Stage: runtime
 
 %files
 	./pyproject.toml /pysr/pyproject.toml
-	./setup.py /pysr/setup.py
+	./LICENSE /pysr/LICENSE
 	./pysr /pysr/pysr
 
 %post

Dockerfile

@@ -20,7 +20,7 @@ WORKDIR /pysr
 # Install PySR:
 # We do a minimal copy so it doesn't need to rerun at every file change:
 ADD ./pyproject.toml /pysr/pyproject.toml
-ADD ./setup.py /pysr/setup.py
+ADD ./LICENSE /pysr/LICENSE
 ADD ./pysr /pysr/pysr
 RUN pip3 install --no-cache-dir .
 

pysr/__init__.py

@@ -19,6 +19,9 @@
 # old libraries:
 from .julia_import import jl, SymbolicRegression  # isort:skip
 
+# Get the version using importlib.metadata (Python >= 3.8 is required):
+from importlib.metadata import PackageNotFoundError, version
+
 from . import sklearn_monkeypatch
 from .deprecated import best, best_callable, best_row, best_tex, install, pysr
 from .export_jax import sympy2jax
@@ -33,8 +36,11 @@
 from .logger_specs import AbstractLoggerSpec, TensorBoardLoggerSpec
 from .sr import PySRRegressor
 
-# This file is created by setuptools_scm during the build process:
-from .version import __version__
+try:
+    __version__ = version("pysr")
+except PackageNotFoundError:  # pragma: no cover
+    # package is not installed
+    __version__ = "unknown"
 
 __all__ = [
     "jl",