encode development requirements in pyproject.toml (#32616)

Add a `project` block to the toml config along with development and CI
dependencies and a minimal `build-system` block, doing basically
nothing, so that spack can be bootstrapped to a full development
environment with:

```shell
$ hatch -e dev shell
```

or for a minimal environment without hatch:

```shell
$ python3 -m venv venv
$ source venv/bin/activate
$ python3 -m pip install --upgrade pip
$ python3 -m pip install -e '.[dev]'
```

This means we can re-use the requirements list throughout the workflow
yaml files and otherwise maintain this list in *one place* rather than
several disparate ones.  We may be stuck with a couple more temporarily
to continue supporting python2.7, but aside from that it's less places
to get out of sync and a couple new bootstrap options.

Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>

1 files changed, 2 insertions, 46 deletions

diff --git a/bin/spack b/bin/spack
index 864fb34a77..08da29dfd2 100755
--- a/bin/spack
+++ b/bin/spack
@@ -49,52 +49,8 @@ spack_prefix = os.path.dirname(os.path.dirname(spack_file))
 spack_lib_path = os.path.join(spack_prefix, "lib", "spack")
 sys.path.insert(0, spack_lib_path)
 
-# Add external libs
-spack_external_libs = os.path.join(spack_lib_path, "external")
-
-if sys.version_info[:2] <= (2, 7):
-    sys.path.insert(0, os.path.join(spack_external_libs, "py2"))
-
-sys.path.insert(0, spack_external_libs)
-
-# Here we delete ruamel.yaml in case it has been already imported from site
-# (see #9206 for a broader description of the issue).
-#
-# Briefly: ruamel.yaml produces a .pth file when installed with pip that
-# makes the site installed package the preferred one, even though sys.path
-# is modified to point to another version of ruamel.yaml.
-if "ruamel.yaml" in sys.modules:
-    del sys.modules["ruamel.yaml"]
-
-if "ruamel" in sys.modules:
-    del sys.modules["ruamel"]
-
-# The following code is here to avoid failures when updating
-# the develop version, due to spurious argparse.pyc files remaining
-# in the libs/spack/external directory, see:
-# https://github.com/spack/spack/pull/25376
-# TODO: Remove in v0.18.0 or later
-try:
-    import argparse
-except ImportError:
-    argparse_pyc = os.path.join(spack_external_libs, "argparse.pyc")
-    if not os.path.exists(argparse_pyc):
-        raise
-    try:
-        os.remove(argparse_pyc)
-        import argparse  # noqa: F401
-    except Exception:
-        msg = (
-            "The file\n\n\t{0}\n\nis corrupted and cannot be deleted by Spack. "
-            "Either delete it manually or ask some administrator to "
-            "delete it for you."
-        )
-        print(msg.format(argparse_pyc))
-        sys.exit(1)
-
-
-import spack.main  # noqa: E402
+from spack_installable.main import main  # noqa: E402
 
 # Once we've set up the system path, run the spack main method
 if __name__ == "__main__":
-    sys.exit(spack.main.main())
+    sys.exit(main())