spack -C <env>: use env config w/o activation (#45046)

Precedence:

1. Named environment
2. Anonymous environment
3. Generic directory

5 files changed, 78 insertions, 43 deletions

diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index 54038ade93..d850a24959 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -796,22 +796,27 @@ def config_paths_from_entry_points() -> List[Tuple[str, str]]:
 def _add_command_line_scopes(
     cfg: Union[Configuration, lang.Singleton], command_line_scopes: List[str]
 ) -> None:
-    """Add additional scopes from the --config-scope argument.
+    """Add additional scopes from the --config-scope argument, either envs or dirs."""
+    import spack.environment.environment as env  # circular import
 
-    Command line scopes are named after their position in the arg list.
-    """
     for i, path in enumerate(command_line_scopes):
-        # We ensure that these scopes exist and are readable, as they are
-        # provided on the command line by the user.
-        if not os.path.isdir(path):
-            raise ConfigError(f"config scope is not a directory: '{path}'")
-        elif not os.access(path, os.R_OK):
-            raise ConfigError(f"config scope is not readable: '{path}'")
-
-        # name based on order on the command line
-        name = f"cmd_scope_{i:d}"
-        cfg.push_scope(DirectoryConfigScope(name, path, writable=False))
-        _add_platform_scope(cfg, name, path, writable=False)
+        name = f"cmd_scope_{i}"
+
+        if env.exists(path):  # managed environment
+            manifest = env.EnvironmentManifestFile(env.root(path))
+        elif env.is_env_dir(path):  # anonymous environment
+            manifest = env.EnvironmentManifestFile(path)
+        elif os.path.isdir(path):  # directory with config files
+            cfg.push_scope(DirectoryConfigScope(name, path, writable=False))
+            _add_platform_scope(cfg, name, path, writable=False)
+            continue
+        else:
+            raise ConfigError(f"Invalid configuration scope: {path}")
+
+        for scope in manifest.env_config_scopes:
+            scope.name = f"{name}:{scope.name}"
+            scope.writable = False
+            cfg.push_scope(scope)
 
 
 def create() -> Configuration:
diff --git a/lib/spack/spack/environment/environment.py b/lib/spack/spack/environment/environment.py
index 501663322e..f3df7e115a 100644
--- a/lib/spack/spack/environment/environment.py
+++ b/lib/spack/spack/environment/environment.py
@@ -269,9 +269,7 @@ def root(name):
 
 def exists(name):
     """Whether an environment with this name exists or not."""
-    if not valid_env_name(name):
-        return False
-    return os.path.isdir(root(name))
+    return valid_env_name(name) and os.path.isdir(_root(name))
 
 
 def active(name):
@@ -922,7 +920,7 @@ class Environment:
     def _load_manifest_file(self):
         """Instantiate and load the manifest file contents into memory."""
         with lk.ReadTransaction(self.txlock):
-            self.manifest = EnvironmentManifestFile(self.path)
+            self.manifest = EnvironmentManifestFile(self.path, self.name)
             with self.manifest.use_config():
                 self._read()
 
@@ -2753,10 +2751,11 @@ class EnvironmentManifestFile(collections.abc.Mapping):
         manifest.flush()
         return manifest
 
-    def __init__(self, manifest_dir: Union[pathlib.Path, str]) -> None:
+    def __init__(self, manifest_dir: Union[pathlib.Path, str], name: Optional[str] = None) -> None:
         self.manifest_dir = pathlib.Path(manifest_dir)
+        self.name = name or str(manifest_dir)
         self.manifest_file = self.manifest_dir / manifest_name
-        self.scope_name = f"env:{environment_name(self.manifest_dir)}"
+        self.scope_name = f"env:{self.name}"
         self.config_stage_dir = os.path.join(env_subdir_path(manifest_dir), "config")
 
         #: Configuration scopes associated with this environment. Note that these are not
@@ -3033,7 +3032,6 @@ class EnvironmentManifestFile(collections.abc.Mapping):
         # load config scopes added via 'include:', in reverse so that
         # highest-precedence scopes are last.
         includes = self[TOP_LEVEL_KEY].get("include", [])
-        env_name = environment_name(self.manifest_dir)
         missing = []
         for i, config_path in enumerate(reversed(includes)):
             # allow paths to contain spack config/environment variables, etc.
@@ -3096,12 +3094,12 @@ class EnvironmentManifestFile(collections.abc.Mapping):
 
             if os.path.isdir(config_path):
                 # directories are treated as regular ConfigScopes
-                config_name = "env:%s:%s" % (env_name, os.path.basename(config_path))
+                config_name = f"env:{self.name}:{os.path.basename(config_path)}"
                 tty.debug(f"Creating DirectoryConfigScope {config_name} for '{config_path}'")
                 scopes.append(spack.config.DirectoryConfigScope(config_name, config_path))
             elif os.path.exists(config_path):
                 # files are assumed to be SingleFileScopes
-                config_name = "env:%s:%s" % (env_name, config_path)
+                config_name = f"env:{self.name}:{config_path}"
                 tty.debug(f"Creating SingleFileScope {config_name} for '{config_path}'")
                 scopes.append(
                     spack.config.SingleFileScope(
diff --git a/lib/spack/spack/main.py b/lib/spack/spack/main.py
index 655fae2f17..78fda27c46 100644
--- a/lib/spack/spack/main.py
+++ b/lib/spack/spack/main.py
@@ -444,8 +444,9 @@ def make_argument_parser(**kwargs):
         "--config-scope",
         dest="config_scopes",
         action="append",
-        metavar="DIR",
-        help="add a custom configuration scope",
+        metavar="DIR|ENV",
+        help="add directory or environment as read-only configuration scope, without activating "
+        "the environment.",
     )
     parser.add_argument(
         "-d",
diff --git a/lib/spack/spack/test/config.py b/lib/spack/spack/test/config.py
index 26a0b37dba..817cfeb40d 100644
--- a/lib/spack/spack/test/config.py
+++ b/lib/spack/spack/test/config.py
@@ -13,7 +13,7 @@ from datetime import date
 import pytest
 
 import llnl.util.tty as tty
-from llnl.util.filesystem import getuid, join_path, mkdirp, touch, touchp
+from llnl.util.filesystem import join_path, touch, touchp
 
 import spack.config
 import spack.directory_layout
@@ -864,26 +864,18 @@ def test_bad_config_section(mock_low_high_config):
         spack.config.get("foobar")
 
 
-@pytest.mark.not_on_windows("chmod not supported on Windows")
-@pytest.mark.skipif(getuid() == 0, reason="user is root")
-def test_bad_command_line_scopes(tmpdir, config):
+def test_bad_command_line_scopes(tmp_path, config):
     cfg = spack.config.Configuration()
+    file_path = tmp_path / "file_instead_of_dir"
+    non_existing_path = tmp_path / "non_existing_dir"
 
-    with tmpdir.as_cwd():
-        with pytest.raises(spack.config.ConfigError):
-            spack.config._add_command_line_scopes(cfg, ["bad_path"])
+    file_path.write_text("")
 
-        touch("unreadable_file")
-        with pytest.raises(spack.config.ConfigError):
-            spack.config._add_command_line_scopes(cfg, ["unreadable_file"])
+    with pytest.raises(spack.config.ConfigError):
+        spack.config._add_command_line_scopes(cfg, [str(file_path)])
 
-        mkdirp("unreadable_dir")
-        with pytest.raises(spack.config.ConfigError):
-            try:
-                os.chmod("unreadable_dir", 0)
-                spack.config._add_command_line_scopes(cfg, ["unreadable_dir"])
-            finally:
-                os.chmod("unreadable_dir", 0o700)  # so tmpdir can be removed
+    with pytest.raises(spack.config.ConfigError):
+        spack.config._add_command_line_scopes(cfg, [str(non_existing_path)])
 
 
 def test_add_command_line_scopes(tmpdir, mutable_config):
@@ -898,6 +890,45 @@ config:
         )
 
     spack.config._add_command_line_scopes(mutable_config, [str(tmpdir)])
+    assert mutable_config.get("config:verify_ssl") is False
+    assert mutable_config.get("config:dirty") is False
+
+
+def test_add_command_line_scope_env(tmp_path, mutable_mock_env_path):
+    """Test whether --config-scope <env> works, either by name or path."""
+    managed_env = ev.create("example").manifest_path
+
+    with open(managed_env, "w") as f:
+        f.write(
+            """\
+spack:
+  config:
+    install_tree:
+      root: /tmp/first
+"""
+        )
+
+    with open(tmp_path / "spack.yaml", "w") as f:
+        f.write(
+            """\
+spack:
+  config:
+    install_tree:
+      root: /tmp/second
+"""
+        )
+
+    config = spack.config.Configuration()
+    spack.config._add_command_line_scopes(config, ["example", str(tmp_path)])
+    assert len(config.scopes) == 2
+    assert config.get("config:install_tree:root") == "/tmp/second"
+
+    config = spack.config.Configuration()
+    spack.config._add_command_line_scopes(config, [str(tmp_path), "example"])
+    assert len(config.scopes) == 2
+    assert config.get("config:install_tree:root") == "/tmp/first"
+
+    assert ev.active_environment() is None  # shouldn't cause an environment to be activated
 
 
 def test_nested_override():
diff --git a/share/spack/spack-completion.fish b/share/spack/spack-completion.fish
index d2d883ff93..f02926e449 100755
--- a/share/spack/spack-completion.fish
+++ b/share/spack/spack-completion.fish
@@ -438,7 +438,7 @@ complete -c spack -n '__fish_spack_using_command ' -l color -r -d 'when to color
 complete -c spack -n '__fish_spack_using_command ' -s c -l config -r -f -a config_vars
 complete -c spack -n '__fish_spack_using_command ' -s c -l config -r -d 'add one or more custom, one off config settings'
 complete -c spack -n '__fish_spack_using_command ' -s C -l config-scope -r -f -a config_scopes
-complete -c spack -n '__fish_spack_using_command ' -s C -l config-scope -r -d 'add a custom configuration scope'
+complete -c spack -n '__fish_spack_using_command ' -s C -l config-scope -r -d 'add directory or environment as read-only configuration scope, without activating the environment.'
 complete -c spack -n '__fish_spack_using_command ' -s d -l debug -f -a debug
 complete -c spack -n '__fish_spack_using_command ' -s d -l debug -d 'write out debug messages'
 complete -c spack -n '__fish_spack_using_command ' -l timestamp -f -a timestamp