spack env create <env>: dir if dir-like (#44024)

A named env cannot contain `.` and `/`.

So when a user runs `spack env create ./here` do not error but treat it
as `spack env create -d ./here`.

Also fix help string of `spack env create`, which seems to have been
copied from `activate` incorrectly.

lib/spack/docs/environments.rst

@@ -142,12 +142,8 @@ user's prompt to begin with the environment name in brackets.
    $ spack env activate -p myenv
    [myenv] $ ...
 
-The ``activate`` command can also be used to create a new environment, if it is
-not already defined, by adding the ``--create`` flag. Managed and anonymous
-environments, anonymous environments are explained in the next section,
-can both be created using the same flags that `spack env create` accepts.
-If an environment already exists then spack will simply activate it and ignore the
-create specific flags.
+The ``activate`` command can also be used to create a new environment if it does not already
+exist.
 
 .. code-block:: console
    
@@ -176,21 +172,36 @@ environment will remove the view from the user environment.
 Anonymous Environments
 ^^^^^^^^^^^^^^^^^^^^^^
 
-Any directory can be treated as an environment if it contains a file
-``spack.yaml``. To load an anonymous environment, use:
+Apart from managed environments, Spack also supports anonymous environments.
+
+Anonymous environments can be placed in any directory of choice.
+
+.. note::
+
+   When uninstalling packages, Spack asks the user to confirm the removal of packages
+   that are still used in a managed environment. This is not the case for anonymous
+   environments.
+
+To create an anonymous environment, use one of the following commands:
 
 .. code-block:: console
 
-   $ spack env activate -d /path/to/directory
+   $ spack env create --dir my_env
+   $ spack env create ./my_env
 
-Anonymous specs can be created in place using the command:
+As a shorthand, you can also create an anonymous environment upon activation if it does not
+already exist:
 
 .. code-block:: console
 
-   $ spack env create -d .
+   $ spack env activate --create ./my_env
+
+For convenience, Spack can also place an anonymous environment in a temporary directory for you:
+
+.. code-block:: console
+
+   $ spack env activate --temp
 
-In this case Spack simply creates a ``spack.yaml`` file in the requested
-directory.
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Environment Sensitive Commands

lib/spack/spack/cmd/env.py

@@ -16,7 +16,7 @@
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
 from llnl.util.tty.colify import colify
-from llnl.util.tty.color import colorize
+from llnl.util.tty.color import cescape, colorize
 
 import spack.cmd
 import spack.cmd.common
@@ -61,14 +61,7 @@
 #
 def env_create_setup_parser(subparser):
     """create a new environment"""
-    subparser.add_argument(
-        "env_name",
-        metavar="env",
-        help=(
-            "name of managed environment or directory of the anonymous env "
-            "(when using --dir/-d) to activate"
-        ),
-    )
+    subparser.add_argument("env_name", metavar="env", help="name or directory of environment")
     subparser.add_argument(
         "-d", "--dir", action="store_true", help="create an environment in a specific directory"
     )
@@ -114,7 +107,7 @@ def env_create(args):
     env = _env_create(
         args.env_name,
         init_file=args.envfile,
-        dir=args.dir,
+        dir=args.dir or os.path.sep in args.env_name or args.env_name in (".", ".."),
         with_view=with_view,
         keep_relative=args.keep_relative,
     )
@@ -123,34 +116,39 @@ def env_create(args):
     env.regenerate_views()
 
 
-def _env_create(name_or_path, *, init_file=None, dir=False, with_view=None, keep_relative=False):
+def _env_create(
+    name_or_path: str,
+    *,
+    init_file: Optional[str] = None,
+    dir: bool = False,
+    with_view: Optional[str] = None,
+    keep_relative: bool = False,
+):
     """Create a new environment, with an optional yaml description.
 
     Arguments:
-        name_or_path (str): name of the environment to create, or path to it
-        init_file (str or file): optional initialization file -- can be
-            a JSON lockfile (*.lock, *.json) or YAML manifest file
-        dir (bool): if True, create an environment in a directory instead
-            of a named environment
-        keep_relative (bool): if True, develop paths are copied verbatim into
-            the new environment file, otherwise they may be made absolute if the
-            new environment is in a different location
+        name_or_path: name of the environment to create, or path to it
+        init_file: optional initialization file -- can be a JSON lockfile (*.lock, *.json) or YAML
+            manifest file
+        dir: if True, create an environment in a directory instead of a managed environment
+        keep_relative: if True, develop paths are copied verbatim into the new environment file,
+            otherwise they may be made absolute if the new environment is in a different location
     """
     if not dir:
         env = ev.create(
             name_or_path, init_file=init_file, with_view=with_view, keep_relative=keep_relative
         )
-        tty.msg("Created environment '%s' in %s" % (name_or_path, env.path))
-        tty.msg("You can activate this environment with:")
-        tty.msg("  spack env activate %s" % (name_or_path))
-        return env
-
+        tty.msg(
+            colorize(
+                f"Created environment @c{{{cescape(env.name)}}} in: @c{{{cescape(env.path)}}}"
+            )
+        )
+    else:
         env = ev.create_in_dir(
             name_or_path, init_file=init_file, with_view=with_view, keep_relative=keep_relative
         )
-    tty.msg("Created environment in %s" % env.path)
-    tty.msg("You can activate this environment with:")
-    tty.msg("  spack env activate %s" % env.path)
+        tty.msg(colorize(f"Created anonymous environment in: @c{{{cescape(env.path)}}}"))
+    tty.msg(f"Activate with: {colorize(f'@c{{spack env activate {cescape(name_or_path)}}}')}")
     return env
 
 

lib/spack/spack/test/cmd/env.py

@@ -3290,7 +3290,7 @@ def test_create_and_activate_managed(tmp_path):
 def test_create_and_activate_anonymous(tmp_path):
     with fs.working_dir(str(tmp_path)):
         env_dir = os.path.join(str(tmp_path), "foo")
-        shell = env("activate", "--without-view", "--create", "--sh", "-d", env_dir)
+        shell = env("activate", "--without-view", "--create", "--sh", env_dir)
         active_env_var = next(line for line in shell.splitlines() if ev.spack_env_var in line)
         assert str(env_dir) in active_env_var
         assert ev.is_env_dir(env_dir)