Add IPython completion to interactive release sessions

Launch IPython with gix imported when run-release receives no Python
arguments. Install IPython only into uv's isolated interactive environment,
and skip IPython configuration/startup files. Keep script and -c arguments
on isolated ordinary Python without adding the interactive dependency.

Validation: helper tests cover both version selections and preserve
Python argument boundaries; just formatting and git diff --check pass.
An explicit Python command still runs offline against the local wheel.
The live IPython prompt could not be tested offline because IPython is
not cached; no package-index installation was performed.

Author: codex

DEVELOPMENT.md

@@ -85,7 +85,8 @@ The package test also verifies importing the extension keeps the GIL disabled.
 
 ## Try a published release
 
-With uv installed, open a Python prompt with `gix` already imported, or run a command:
+With uv installed, open an IPython prompt with `gix` already imported and Tab
+completion available, or run a Python command:
 
 ```sh
 just run-release
@@ -99,6 +100,9 @@ into an isolated uv virtualenv. It refreshes release resolution on each invocati
 uses the installed `PYTHON` interpreter, and requires a matching binary wheel;
 it does not build sources or install build tools. Python runs in isolated mode
 so inherited `PYTHONPATH` and the checkout's extension cannot shadow the release.
+Interactive sessions also install IPython into that virtualenv and skip loading
+IPython startup files and configuration. Script and `-c` arguments continue to
+use ordinary Python without installing IPython.
 Pass `latest` before any Python arguments; set `PYTHON` to an installed
 free-threaded interpreter to try its wheel. These commands read PyPI when invoked.
 Development builds continue using the local selection described above.

etc/test_justfile.py

@@ -21,20 +21,23 @@ def test_release_selection_and_python_arguments(self):
             stub.chmod(0o755)
             env = dict(os.environ, PATH=directory + os.pathsep + os.environ["PATH"], PYTHON=sys.executable,
                        PYTHONPATH=str(root / "python"))
+            interactive = ["--with", "ipython", "python", "-I", "-m", "IPython", "--quick", "-i", "-c",
+                           'import gix; print("GixPython", gix.__version__)']
             for arguments, package, python_args in (
-                ([], "GixPython", ["-i", "-c", 'import gix; print("GixPython", gix.__version__)']),
+                ([], "GixPython", interactive),
+                (["0.1.0"], "GixPython==0.1.0", interactive),
                 (["0.1.0", "-c", "import gix; print(gix.__version__)"], "GixPython==0.1.0",
-                 ["-c", "import gix; print(gix.__version__)"]),
+                 ["python", "-I", "-c", "import gix; print(gix.__version__)"]),
                 (["latest", "script with spaces.py", "argument with spaces"], "GixPython",
-                 ["script with spaces.py", "argument with spaces"]),
+                 ["python", "-I", "script with spaces.py", "argument with spaces"]),
             ):
                 with self.subTest(arguments=arguments):
                     result = subprocess.run(["just", "--justfile", str(root / "justfile"), "run-release", *arguments],
                                             cwd=root, env=env, check=True, capture_output=True, text=True)
                     command = json.loads(result.stdout)
                     self.assertEqual(command, ["run", "--no-project", "--isolated", "--no-python-downloads",
                                                "--python", sys.executable, "--no-build", "--upgrade-package",
-                                               "GixPython", "--with", package, "python", "-I", *python_args])
+                                               "GixPython", "--with", package, *python_args])
 
 
 if __name__ == "__main__":

justfile

@@ -59,13 +59,15 @@ artifacts *args:
     maturin build --sdist --release --locked --out dist --interpreter {{ quote(python) }} "$@"
     {{ quote(python) }} etc/check_artifact.py dist/*.tar.gz dist/*.whl
 
-# Run the latest or a specified release in an isolated uv virtualenv (requires a wheel).
+# Explore a release in IPython with completion, or run Python arguments in an isolated uv virtualenv.
 [group('Releases')]
 [positional-arguments]
 run-release version='latest' *args:
     version="$1"; shift; \
         package=GixPython; \
         if [ "$version" != latest ]; then package="GixPython==$version"; fi; \
-        if [ "$#" -eq 0 ]; then set -- -i -c 'import gix; print("GixPython", gix.__version__)'; fi; \
+        if [ "$#" -eq 0 ]; then \
+            set -- --with ipython python -I -m IPython --quick -i -c 'import gix; print("GixPython", gix.__version__)'; \
+        else set -- python -I "$@"; fi; \
         uv run --no-project --isolated --no-python-downloads --python {{ quote(python) }} \
-            --no-build --upgrade-package GixPython --with "$package" python -I "$@"
+            --no-build --upgrade-package GixPython --with "$package" "$@"