Add GraalPy and test both GraalPy and Jython env identifiers (#3312)

docs/changelog/3312.feature.rst

@@ -0,0 +1 @@
+Add "graalpy" prefix as a supported base python

docs/user_guide.rst

@@ -116,6 +116,7 @@ implementations of Python and provide default values for ``base_python``:
 - ``cpythonNM``: configures ``basepython = cpythonN.M``
 - ``ironpythonNM``: configures ``basepython = ironpythonN.M``
 - ``rustpythonNM``: configures ``basepython = rustpythonN.M``
+- ``graalpyNM``: configures ``basepython = graalpyN.M``
 
 You can also specify these factors with a period between the major and minor versions (e.g. ``pyN.M``), without a minor
 version (e.g. ``pyN``), or without any version information whatsoever (e.g. ``py``)

src/tox/tox_env/python/api.py

@@ -51,7 +51,7 @@ def version_dot(self) -> str:
 PY_FACTORS_RE = re.compile(
     r"""
     ^(?!py$)                                               # don't match 'py' as it doesn't provide any info
-    (?P<impl>py|pypy|cpython|jython|rustpython|ironpython) # the interpreter; most users will simply use 'py'
+    (?P<impl>py|pypy|cpython|jython|graalpy|rustpython|ironpython) # the interpreter; most users will simply use 'py'
     (?P<version>[2-9]\.?[0-9]?[0-9]?)?$                    # the version; one of: MAJORMINOR, MAJOR.MINOR
     """,
     re.VERBOSE,

tests/tox_env/python/test_python_api.py

@@ -84,6 +84,8 @@ def test_diff_msg_no_diff() -> None:
         ("py3.12", "py3.12"),
         ("pypy2", "pypy2"),
         ("rustpython3", "rustpython3"),
+        ("graalpy", "graalpy"),
+        ("jython", "jython"),
         ("cpython3.8", "cpython3.8"),
         ("ironpython2.7", "ironpython2.7"),
         ("functional-py310", "py310"),