Partial removal of circular dependencies between `spack` and `llnl` (#40090)

Modifications:
- [x] Move `spack.util.string` to `llnl.string`
- [x] Remove dependency of `llnl` on `spack.error`
- [x] Move path of `spack.util.path` to `llnl.path`
- [x] Move `spack.util.environment.get_host_*` to `spack.spec`

30 files changed, 297 insertions, 258 deletions

diff --git a/lib/spack/llnl/path.py b/lib/spack/llnl/path.py
new file mode 100644
index 0000000000..bef9e14ada
--- /dev/null
+++ b/lib/spack/llnl/path.py
@@ -0,0 +1,105 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+"""Path primitives that just require Python standard library."""
+import functools
+import sys
+from typing import List, Optional
+from urllib.parse import urlparse
+
+
+class Path:
+    """Enum to identify the path-style."""
+
+    unix: int = 0
+    windows: int = 1
+    platform_path: int = windows if sys.platform == "win32" else unix
+
+
+def format_os_path(path: str, mode: int = Path.unix) -> str:
+    """Formats the input path to use consistent, platform specific separators.
+
+    Absolute paths are converted between drive letters and a prepended '/' as per platform
+    requirement.
+
+    Parameters:
+        path: the path to be normalized, must be a string or expose the replace method.
+        mode: the path file separator style to normalize the passed path to.
+            Default is unix style, i.e. '/'
+    """
+    if not path:
+        return path
+    if mode == Path.windows:
+        path = path.replace("/", "\\")
+    else:
+        path = path.replace("\\", "/")
+    return path
+
+
+def convert_to_posix_path(path: str) -> str:
+    """Converts the input path to POSIX style."""
+    return format_os_path(path, mode=Path.unix)
+
+
+def convert_to_windows_path(path: str) -> str:
+    """Converts the input path to Windows style."""
+    return format_os_path(path, mode=Path.windows)
+
+
+def convert_to_platform_path(path: str) -> str:
+    """Converts the input path to the current platform's native style."""
+    return format_os_path(path, mode=Path.platform_path)
+
+
+def path_to_os_path(*parameters: str) -> List[str]:
+    """Takes an arbitrary number of positional parameters, converts each argument of type
+    string to use a normalized filepath separator, and returns a list of all values.
+    """
+
+    def _is_url(path_or_url: str) -> bool:
+        if "\\" in path_or_url:
+            return False
+        url_tuple = urlparse(path_or_url)
+        return bool(url_tuple.scheme) and len(url_tuple.scheme) > 1
+
+    result = []
+    for item in parameters:
+        if isinstance(item, str) and not _is_url(item):
+            item = convert_to_platform_path(item)
+        result.append(item)
+    return result
+
+
+def system_path_filter(_func=None, arg_slice: Optional[slice] = None):
+    """Filters function arguments to account for platform path separators.
+    Optional slicing range can be specified to select specific arguments
+
+    This decorator takes all (or a slice) of a method's positional arguments
+    and normalizes usage of filepath separators on a per platform basis.
+
+    Note: `**kwargs`, urls, and any type that is not a string are ignored
+    so in such cases where path normalization is required, that should be
+    handled by calling path_to_os_path directly as needed.
+
+    Parameters:
+        arg_slice: a slice object specifying the slice of arguments
+            in the decorated method over which filepath separators are
+            normalized
+    """
+
+    def holder_func(func):
+        @functools.wraps(func)
+        def path_filter_caller(*args, **kwargs):
+            args = list(args)
+            if arg_slice:
+                args[arg_slice] = path_to_os_path(*args[arg_slice])
+            else:
+                args = path_to_os_path(*args)
+            return func(*args, **kwargs)
+
+        return path_filter_caller
+
+    if _func:
+        return holder_func(_func)
+    return holder_func
diff --git a/lib/spack/llnl/string.py b/lib/spack/llnl/string.py
new file mode 100644
index 0000000000..a203be8d34
--- /dev/null
+++ b/lib/spack/llnl/string.py
@@ -0,0 +1,67 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+"""String manipulation functions that do not have other dependencies than Python
+standard library
+"""
+from typing import List, Optional
+
+
+def comma_list(sequence: List[str], article: str = "") -> str:
+    if type(sequence) is not list:
+        sequence = list(sequence)
+
+    if not sequence:
+        return ""
+    if len(sequence) == 1:
+        return sequence[0]
+
+    out = ", ".join(str(s) for s in sequence[:-1])
+    if len(sequence) != 2:
+        out += ","  # oxford comma
+    out += " "
+    if article:
+        out += article + " "
+    out += str(sequence[-1])
+    return out
+
+
+def comma_or(sequence: List[str]) -> str:
+    """Return a string with all the elements of the input joined by comma, but the last
+    one (which is joined by 'or').
+    """
+    return comma_list(sequence, "or")
+
+
+def comma_and(sequence: List[str]) -> str:
+    """Return a string with all the elements of the input joined by comma, but the last
+    one (which is joined by 'and').
+    """
+    return comma_list(sequence, "and")
+
+
+def quote(sequence: List[str], q: str = "'") -> List[str]:
+    """Quotes each item in the input list with the quote character passed as second argument."""
+    return [f"{q}{e}{q}" for e in sequence]
+
+
+def plural(n: int, singular: str, plural: Optional[str] = None, show_n: bool = True) -> str:
+    """Pluralize <singular> word by adding an s if n != 1.
+
+    Arguments:
+        n: number of things there are
+        singular: singular form of word
+        plural: optional plural form, for when it's not just singular + 's'
+        show_n: whether to include n in the result string (default True)
+
+    Returns:
+        "1 thing" if n == 1 or "n things" if n != 1
+    """
+    number = f"{n} " if show_n else ""
+    if n == 1:
+        return f"{number}{singular}"
+    elif plural is not None:
+        return f"{number}{plural}"
+    else:
+        return f"{number}{singular}s"
diff --git a/lib/spack/llnl/util/filesystem.py b/lib/spack/llnl/util/filesystem.py
index bd203ef200..8f4217049d 100644
--- a/lib/spack/llnl/util/filesystem.py
+++ b/lib/spack/llnl/util/filesystem.py
@@ -28,7 +28,8 @@ from llnl.util.lang import dedupe, memoized
 from llnl.util.symlink import islink, readlink, resolve_link_target_relative_to_the_link, symlink
 
 from spack.util.executable import Executable, which
-from spack.util.path import path_to_os_path, system_path_filter
+
+from ..path import path_to_os_path, system_path_filter
 
 if sys.platform != "win32":
     import grp
@@ -336,8 +337,7 @@ def filter_file(
 
     if string:
         regex = re.escape(regex)
-    filenames = path_to_os_path(*filenames)
-    for filename in filenames:
+    for filename in path_to_os_path(*filenames):
         msg = 'FILTER FILE: {0} [replacing "{1}"]'
         tty.debug(msg.format(filename, regex))
 
diff --git a/lib/spack/llnl/util/lock.py b/lib/spack/llnl/util/lock.py
index 74a325acd2..156300b891 100644
--- a/lib/spack/llnl/util/lock.py
+++ b/lib/spack/llnl/util/lock.py
@@ -14,7 +14,7 @@ from typing import IO, Any, Callable, ContextManager, Dict, Generator, Optional,
 
 from llnl.util import lang, tty
 
-import spack.util.string
+from ..string import plural
 
 if sys.platform != "win32":
     import fcntl
@@ -169,7 +169,7 @@ def _attempts_str(wait_time, nattempts):
     if nattempts <= 1:
         return ""
 
-    attempts = spack.util.string.plural(nattempts, "attempt")
+    attempts = plural(nattempts, "attempt")
     return " after {} and {}".format(lang.pretty_seconds(wait_time), attempts)
 
 
diff --git a/lib/spack/llnl/util/symlink.py b/lib/spack/llnl/util/symlink.py
index ab6654e847..4f4f965f13 100644
--- a/lib/spack/llnl/util/symlink.py
+++ b/lib/spack/llnl/util/symlink.py
@@ -11,8 +11,7 @@ import tempfile
 
 from llnl.util import lang, tty
 
-from spack.error import SpackError
-from spack.util.path import system_path_filter
+from ..path import system_path_filter
 
 if sys.platform == "win32":
     from win32file import CreateHardLink
@@ -338,7 +337,7 @@ def resolve_link_target_relative_to_the_link(link):
     return os.path.join(link_dir, target)
 
 
-class SymlinkError(SpackError):
+class SymlinkError(RuntimeError):
     """Exception class for errors raised while creating symlinks,
     junctions and hard links
     """
diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index 723f398ae6..881fcb5c9c 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -43,6 +43,7 @@ import types
 from typing import List, Tuple
 
 import llnl.util.tty as tty
+from llnl.string import plural
 from llnl.util.filesystem import join_path
 from llnl.util.lang import dedupe
 from llnl.util.symlink import symlink
@@ -82,7 +83,6 @@ from spack.util.environment import (
 from spack.util.executable import Executable
 from spack.util.log_parse import make_log_context, parse_log_events
 from spack.util.module_cmd import load_module, module, path_from_modules
-from spack.util.string import plural
 
 #
 # This can be set by the user to globally disable parallel builds.
diff --git a/lib/spack/spack/cmd/__init__.py b/lib/spack/spack/cmd/__init__.py
index fd5e81fe7a..c26ab181c1 100644
--- a/lib/spack/spack/cmd/__init__.py
+++ b/lib/spack/spack/cmd/__init__.py
@@ -11,6 +11,7 @@ import sys
 from textwrap import dedent
 from typing import List, Match, Tuple
 
+import llnl.string
 import llnl.util.tty as tty
 from llnl.util.filesystem import join_path
 from llnl.util.lang import attr_setdefault, index_by
@@ -29,7 +30,6 @@ import spack.traverse as traverse
 import spack.user_environment as uenv
 import spack.util.spack_json as sjson
 import spack.util.spack_yaml as syaml
-import spack.util.string
 
 # cmd has a submodule called "list" so preserve the python list module
 python_list = list
@@ -516,7 +516,7 @@ def print_how_many_pkgs(specs, pkg_type=""):
             category, e.g. if pkg_type is "installed" then the message
             would be "3 installed packages"
     """
-    tty.msg("%s" % spack.util.string.plural(len(specs), pkg_type + " package"))
+    tty.msg("%s" % llnl.string.plural(len(specs), pkg_type + " package"))
 
 
 def spack_is_git_repo():
diff --git a/lib/spack/spack/cmd/buildcache.py b/lib/spack/spack/cmd/buildcache.py
index f611956c36..5eb0ea1ed4 100644
--- a/lib/spack/spack/cmd/buildcache.py
+++ b/lib/spack/spack/cmd/buildcache.py
@@ -13,6 +13,7 @@ from typing import List
 
 import llnl.util.tty as tty
 import llnl.util.tty.color as clr
+from llnl.string import plural
 from llnl.util.lang import elide_list
 
 import spack.binary_distribution as bindist
@@ -32,7 +33,6 @@ import spack.util.web as web_util
 from spack.cmd import display_specs
 from spack.spec import Spec, save_dependency_specfiles
 from spack.stage import Stage
-from spack.util.string import plural
 
 description = "create, download and install binary packages"
 section = "packaging"
diff --git a/lib/spack/spack/cmd/env.py b/lib/spack/spack/cmd/env.py
index 8a2f129bda..6c22e70a5d 100644
--- a/lib/spack/spack/cmd/env.py
+++ b/lib/spack/spack/cmd/env.py
@@ -9,6 +9,7 @@ import shutil
 import sys
 import tempfile
 
+import llnl.string as string
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
 from llnl.util.tty.colify import colify
@@ -28,7 +29,6 @@ import spack.environment.shell
 import spack.schema.env
 import spack.spec
 import spack.tengine
-import spack.util.string as string
 from spack.util.environment import EnvironmentModifications
 
 description = "manage virtual environments"
diff --git a/lib/spack/spack/cmd/make_installer.py b/lib/spack/spack/cmd/make_installer.py
index 7f43659429..986631d39f 100644
--- a/lib/spack/spack/cmd/make_installer.py
+++ b/lib/spack/spack/cmd/make_installer.py
@@ -6,10 +6,11 @@ import os
 import posixpath
 import sys
 
+from llnl.path import convert_to_posix_path
+
 import spack.paths
 import spack.util.executable
 from spack.spec import Spec
-from spack.util.path import convert_to_posix_path
 
 description = "generate Windows installer"
 section = "admin"
diff --git a/lib/spack/spack/cmd/tags.py b/lib/spack/spack/cmd/tags.py
index 0aa6acfd5f..0fbc91b6f4 100644
--- a/lib/spack/spack/cmd/tags.py
+++ b/lib/spack/spack/cmd/tags.py
@@ -5,6 +5,7 @@
 import io
 import sys
 
+import llnl.string
 import llnl.util.tty as tty
 import llnl.util.tty.colify as colify
 
@@ -24,7 +25,7 @@ def report_tags(category, tags):
     if isatty:
         num = len(tags)
         fmt = "{0} package tag".format(category)
-        buffer.write("{0}:\n".format(spack.util.string.plural(num, fmt)))
+        buffer.write("{0}:\n".format(llnl.string.plural(num, fmt)))
 
     if tags:
         colify.colify(tags, output=buffer, tty=isatty, indent=4)
diff --git a/lib/spack/spack/compiler.py b/lib/spack/spack/compiler.py
index 3ec7d1421a..70da3ca2c4 100644
--- a/lib/spack/spack/compiler.py
+++ b/lib/spack/spack/compiler.py
@@ -13,6 +13,7 @@ import sys
 import tempfile
 from typing import List, Optional, Sequence
 
+import llnl.path
 import llnl.util.lang
 import llnl.util.tty as tty
 from llnl.util.filesystem import path_contains_subdirectory, paths_containing_libs
@@ -24,7 +25,6 @@ import spack.util.executable
 import spack.util.module_cmd
 import spack.version
 from spack.util.environment import filter_system_paths
-from spack.util.path import system_path_filter
 
 __all__ = ["Compiler"]
 
@@ -160,7 +160,7 @@ def _parse_link_paths(string):
     return implicit_link_dirs
 
 
-@system_path_filter
+@llnl.path.system_path_filter
 def _parse_non_system_link_dirs(string: str) -> List[str]:
     """Parses link paths out of compiler debug output.
 
diff --git a/lib/spack/spack/directory_layout.py b/lib/spack/spack/directory_layout.py
index dd4e6dd5e1..46bb6c8557 100644
--- a/lib/spack/spack/directory_layout.py
+++ b/lib/spack/spack/directory_layout.py
@@ -120,10 +120,8 @@ class DirectoryLayout:
         versioning. We use it in the case that an analysis later needs to
         easily access this information.
         """
-        from spack.util.environment import get_host_environment_metadata
-
         env_file = self.env_metadata_path(spec)
-        environ = get_host_environment_metadata()
+        environ = spack.spec.get_host_environment_metadata()
         with open(env_file, "w") as fd:
             sjson.dump(environ, fd)
 
diff --git a/lib/spack/spack/environment/environment.py b/lib/spack/spack/environment/environment.py
index d8f04c7d4b..496a8b332a 100644
--- a/lib/spack/spack/environment/environment.py
+++ b/lib/spack/spack/environment/environment.py
@@ -404,7 +404,7 @@ def _write_yaml(data, str_or_file):
 
 def _eval_conditional(string):
     """Evaluate conditional definitions using restricted variable scope."""
-    valid_variables = spack.util.environment.get_host_environment()
+    valid_variables = spack.spec.get_host_environment()
     valid_variables.update({"re": re, "env": os.environ})
     return eval(string, valid_variables)
 
diff --git a/lib/spack/spack/fetch_strategy.py b/lib/spack/spack/fetch_strategy.py
index 90ff8527fd..8578b110fc 100644
--- a/lib/spack/spack/fetch_strategy.py
+++ b/lib/spack/spack/fetch_strategy.py
@@ -35,6 +35,7 @@ import llnl.url
 import llnl.util
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
+from llnl.string import comma_and, quote
 from llnl.util.filesystem import get_single_file, mkdirp, temp_cwd, temp_rename, working_dir
 from llnl.util.symlink import symlink
 
@@ -49,7 +50,6 @@ import spack.version
 import spack.version.git_ref_lookup
 from spack.util.compression import decompressor_for
 from spack.util.executable import CommandNotFoundError, which
-from spack.util.string import comma_and, quote
 
 #: List of all fetch strategies, created by FetchStrategy metaclass.
 all_strategies = []
diff --git a/lib/spack/spack/install_test.py b/lib/spack/spack/install_test.py
index 90359796d8..0d8fa782b6 100644
--- a/lib/spack/spack/install_test.py
+++ b/lib/spack/spack/install_test.py
@@ -17,6 +17,7 @@ from typing import Callable, List, Optional, Tuple, Type, TypeVar, Union
 
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
+from llnl.string import plural
 from llnl.util.lang import nullcontext
 from llnl.util.tty.color import colorize
 
@@ -26,7 +27,6 @@ import spack.util.spack_json as sjson
 from spack.installer import InstallError
 from spack.spec import Spec
 from spack.util.prefix import Prefix
-from spack.util.string import plural
 
 #: Stand-alone test failure info type
 TestFailureType = Tuple[BaseException, str]
diff --git a/lib/spack/spack/repo.py b/lib/spack/spack/repo.py
index a4362d9d31..4391d9a9a2 100644
--- a/lib/spack/spack/repo.py
+++ b/lib/spack/spack/repo.py
@@ -26,6 +26,7 @@ import types
 import uuid
 from typing import Any, Dict, List, Union
 
+import llnl.path
 import llnl.util.filesystem as fs
 import llnl.util.lang
 import llnl.util.tty as tty
@@ -563,7 +564,7 @@ class RepoIndex:
         self.checker = package_checker
         self.packages_path = self.checker.packages_path
         if sys.platform == "win32":
-            self.packages_path = spack.util.path.convert_to_posix_path(self.packages_path)
+            self.packages_path = llnl.path.convert_to_posix_path(self.packages_path)
         self.namespace = namespace
 
         self.indexers: Dict[str, Indexer] = {}
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index 13bf66f506..85a638b602 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -54,10 +54,14 @@ import enum
 import io
 import itertools
 import os
+import platform
 import re
+import socket
 import warnings
-from typing import Callable, List, Optional, Tuple, Union
+from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
+import llnl.path
+import llnl.string
 import llnl.util.filesystem as fs
 import llnl.util.lang as lang
 import llnl.util.tty as tty
@@ -82,11 +86,9 @@ import spack.util.crypto
 import spack.util.executable
 import spack.util.hash
 import spack.util.module_cmd as md
-import spack.util.path as pth
 import spack.util.prefix
 import spack.util.spack_json as sjson
 import spack.util.spack_yaml as syaml
-import spack.util.string
 import spack.variant as vt
 import spack.version as vn
 import spack.version.git_ref_lookup
@@ -1390,7 +1392,7 @@ class Spec:
 
     @property
     def external_path(self):
-        return pth.path_to_os_path(self._external_path)[0]
+        return llnl.path.path_to_os_path(self._external_path)[0]
 
     @external_path.setter
     def external_path(self, ext_path):
@@ -1799,7 +1801,7 @@ class Spec:
 
     @prefix.setter
     def prefix(self, value):
-        self._prefix = spack.util.prefix.Prefix(pth.convert_to_platform_path(value))
+        self._prefix = spack.util.prefix.Prefix(llnl.path.convert_to_platform_path(value))
 
     def spec_hash(self, hash):
         """Utility method for computing different types of Spec hashes.
@@ -5148,6 +5150,43 @@ def save_dependency_specfiles(root: Spec, output_directory: str, dependencies: L
             fd.write(spec.to_json(hash=ht.dag_hash))
 
 
+def get_host_environment_metadata() -> Dict[str, str]:
+    """Get the host environment, reduce to a subset that we can store in
+    the install directory, and add the spack version.
+    """
+    import spack.main
+
+    environ = get_host_environment()
+    return {
+        "host_os": environ["os"],
+        "platform": environ["platform"],
+        "host_target": environ["target"],
+        "hostname": environ["hostname"],
+        "spack_version": spack.main.get_version(),
+        "kernel_version": platform.version(),
+    }
+
+
+def get_host_environment() -> Dict[str, Any]:
+    """Return a dictionary (lookup) with host information (not including the
+    os.environ).
+    """
+    host_platform = spack.platforms.host()
+    host_target = host_platform.target("default_target")
+    host_os = host_platform.operating_system("default_os")
+    arch_fmt = "platform={0} os={1} target={2}"
+    arch_spec = Spec(arch_fmt.format(host_platform, host_os, host_target))
+    return {
+        "target": str(host_target),
+        "os": str(host_os),
+        "platform": str(host_platform),
+        "arch": arch_spec,
+        "architecture": arch_spec,
+        "arch_str": str(arch_spec),
+        "hostname": socket.gethostname(),
+    }
+
+
 class SpecParseError(spack.error.SpecError):
     """Wrapper for ParseError for when we're parsing specs."""
 
@@ -5208,7 +5247,7 @@ class InvalidDependencyError(spack.error.SpecError):
     def __init__(self, pkg, deps):
         self.invalid_deps = deps
         super().__init__(
-            "Package {0} does not depend on {1}".format(pkg, spack.util.string.comma_or(deps))
+            "Package {0} does not depend on {1}".format(pkg, llnl.string.comma_or(deps))
         )
 
 
diff --git a/lib/spack/spack/stage.py b/lib/spack/spack/stage.py
index 065f74eb8b..73b82c1378 100644
--- a/lib/spack/spack/stage.py
+++ b/lib/spack/spack/stage.py
@@ -14,6 +14,7 @@ import sys
 import tempfile
 from typing import Callable, Dict, Iterable, Optional
 
+import llnl.string
 import llnl.util.lang
 import llnl.util.tty as tty
 from llnl.util.filesystem import (
@@ -37,7 +38,6 @@ import spack.spec
 import spack.util.lock
 import spack.util.path as sup
 import spack.util.pattern as pattern
-import spack.util.string
 import spack.util.url as url_util
 from spack.util.crypto import bit_length, prefix_bits
 
@@ -897,7 +897,7 @@ def get_checksums_for_versions(
     num_ver = len(sorted_versions)
 
     tty.msg(
-        f"Found {spack.util.string.plural(num_ver, 'version')} of {package_name}:",
+        f"Found {llnl.string.plural(num_ver, 'version')} of {package_name}:",
         "",
         *llnl.util.lang.elide_list(
             ["{0:{1}}  {2}".format(str(v), max_len, url_by_version[v]) for v in sorted_versions]
diff --git a/lib/spack/spack/test/build_environment.py b/lib/spack/spack/test/build_environment.py
index 90f3fb378e..2eb80fded3 100644
--- a/lib/spack/spack/test/build_environment.py
+++ b/lib/spack/spack/test/build_environment.py
@@ -9,6 +9,7 @@ import posixpath
 
 import pytest
 
+from llnl.path import Path, convert_to_platform_path
 from llnl.util.filesystem import HeaderList, LibraryList
 
 import spack.build_environment
@@ -21,7 +22,6 @@ from spack.paths import build_env_path
 from spack.util.cpus import determine_number_of_jobs
 from spack.util.environment import EnvironmentModifications
 from spack.util.executable import Executable
-from spack.util.path import Path, convert_to_platform_path
 
 
 def os_pathsep_join(path, *pths):
diff --git a/lib/spack/spack/test/cmd/bootstrap.py b/lib/spack/spack/test/cmd/bootstrap.py
index 35f6987bec..eff9bf042d 100644
--- a/lib/spack/spack/test/cmd/bootstrap.py
+++ b/lib/spack/spack/test/cmd/bootstrap.py
@@ -7,13 +7,14 @@ import sys
 
 import pytest
 
+from llnl.path import convert_to_posix_path
+
 import spack.bootstrap
 import spack.bootstrap.core
 import spack.config
 import spack.environment as ev
 import spack.main
 import spack.mirror
-from spack.util.path import convert_to_posix_path
 
 _bootstrap = spack.main.SpackCommand("bootstrap")
 
diff --git a/lib/spack/spack/test/directory_layout.py b/lib/spack/spack/test/directory_layout.py
index 995707db23..64676bfebc 100644
--- a/lib/spack/spack/test/directory_layout.py
+++ b/lib/spack/spack/test/directory_layout.py
@@ -12,11 +12,12 @@ from pathlib import Path
 
 import pytest
 
+from llnl.path import path_to_os_path
+
 import spack.paths
 import spack.repo
 from spack.directory_layout import DirectoryLayout, InvalidDirectoryLayoutParametersError
 from spack.spec import Spec
-from spack.util.path import path_to_os_path
 
 # number of packages to test (to reduce test time)
 max_packages = 10
diff --git a/lib/spack/spack/test/llnl/llnl_string.py b/lib/spack/spack/test/llnl/llnl_string.py
new file mode 100644
index 0000000000..93d7e662c5
--- /dev/null
+++ b/lib/spack/spack/test/llnl/llnl_string.py
@@ -0,0 +1,43 @@
+# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import pytest
+
+import llnl.string
+
+
+@pytest.mark.parametrize(
+    "arguments,expected",
+    [
+        ((0, "thing"), "0 things"),
+        ((1, "thing"), "1 thing"),
+        ((2, "thing"), "2 things"),
+        ((1, "thing", "wombats"), "1 thing"),
+        ((2, "thing", "wombats"), "2 wombats"),
+        ((2, "thing", "wombats", False), "wombats"),
+    ],
+)
+def test_plural(arguments, expected):
+    assert llnl.string.plural(*arguments) == expected
+
+
+@pytest.mark.parametrize(
+    "arguments,expected",
+    [((["one", "two"],), ["'one'", "'two'"]), ((["one", "two"], "^"), ["^one^", "^two^"])],
+)
+def test_quote(arguments, expected):
+    assert llnl.string.quote(*arguments) == expected
+
+
+@pytest.mark.parametrize(
+    "input,expected_and,expected_or",
+    [
+        (["foo"], "foo", "foo"),
+        (["foo", "bar"], "foo and bar", "foo or bar"),
+        (["foo", "bar", "baz"], "foo, bar, and baz", "foo, bar, or baz"),
+    ],
+)
+def test_comma_and_or(input, expected_and, expected_or):
+    assert llnl.string.comma_and(input) == expected_and
+    assert llnl.string.comma_or(input) == expected_or
diff --git a/lib/spack/spack/test/util/util_string.py b/lib/spack/spack/test/util/util_string.py
deleted file mode 100644
index f4de373859..0000000000
--- a/lib/spack/spack/test/util/util_string.py
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-from spack.util.string import plural
-
-
-def test_plural():
-    assert plural(0, "thing") == "0 things"
-    assert plural(1, "thing") == "1 thing"
-    assert plural(2, "thing") == "2 things"
-    assert plural(1, "thing", "wombats") == "1 thing"
-    assert plural(2, "thing", "wombats") == "2 wombats"
diff --git a/lib/spack/spack/url.py b/lib/spack/spack/url.py
index c5e47232c0..080c924596 100644
--- a/lib/spack/spack/url.py
+++ b/lib/spack/spack/url.py
@@ -31,12 +31,12 @@ import pathlib
 import re
 
 import llnl.url
+from llnl.path import convert_to_posix_path
 from llnl.util.tty.color import cescape, colorize
 
 import spack.error
 import spack.util.web
 import spack.version
-from spack.util.path import convert_to_posix_path
 
 #
 # Note: We call the input to most of these functions a "path" but the functions
diff --git a/lib/spack/spack/util/environment.py b/lib/spack/spack/util/environment.py
index c18be76cc6..246df65cb8 100644
--- a/lib/spack/spack/util/environment.py
+++ b/lib/spack/spack/util/environment.py
@@ -10,21 +10,16 @@ import json
 import os
 import os.path
 import pickle
-import platform
 import re
-import socket
 import sys
 from functools import wraps
 from typing import Any, Callable, Dict, List, MutableMapping, Optional, Tuple, Union
 
+from llnl.path import path_to_os_path, system_path_filter
 from llnl.util import tty
 from llnl.util.lang import dedupe
 
-import spack.platforms
-import spack.spec
-
 from .executable import Executable, which
-from .path import path_to_os_path, system_path_filter
 
 if sys.platform == "win32":
     SYSTEM_PATHS = [
@@ -224,43 +219,6 @@ def pickle_environment(path: Path, environment: Optional[Dict[str, str]] = None)
         pickle.dump(dict(environment if environment else os.environ), pickle_file, protocol=2)
 
 
-def get_host_environment_metadata() -> Dict[str, str]:
-    """Get the host environment, reduce to a subset that we can store in
-    the install directory, and add the spack version.
-    """
-    import spack.main
-
-    environ = get_host_environment()
-    return {
-        "host_os": environ["os"],
-        "platform": environ["platform"],
-        "host_target": environ["target"],
-        "hostname": environ["hostname"],
-        "spack_version": spack.main.get_version(),
-        "kernel_version": platform.version(),
-    }
-
-
-def get_host_environment() -> Dict[str, Any]:
-    """Return a dictionary (lookup) with host information (not including the
-    os.environ).
-    """
-    host_platform = spack.platforms.host()
-    host_target = host_platform.target("default_target")
-    host_os = host_platform.operating_system("default_os")
-    arch_fmt = "platform={0} os={1} target={2}"
-    arch_spec = spack.spec.Spec(arch_fmt.format(host_platform, host_os, host_target))
-    return {
-        "target": str(host_target),
-        "os": str(host_os),
-        "platform": str(host_platform),
-        "arch": arch_spec,
-        "architecture": arch_spec,
-        "arch_str": str(arch_spec),
-        "hostname": socket.gethostname(),
-    }
-
-
 @contextlib.contextmanager
 def set_env(**kwargs):
     """Temporarily sets and restores environment variables.
diff --git a/lib/spack/spack/util/path.py b/lib/spack/spack/util/path.py
index 3dc0ea676c..a46443c083 100644
--- a/lib/spack/spack/util/path.py
+++ b/lib/spack/spack/util/path.py
@@ -15,7 +15,6 @@ import subprocess
 import sys
 import tempfile
 from datetime import date
-from urllib.parse import urlparse
 
 import llnl.util.tty as tty
 from llnl.util.lang import memoized
@@ -98,31 +97,10 @@ SPACK_MAX_INSTALL_PATH_LENGTH = 300
 SPACK_PATH_PADDING_CHARS = "__spack_path_placeholder__"
 
 
-def is_path_url(path):
-    if "\\" in path:
-        return False
-    url_tuple = urlparse(path)
-    return bool(url_tuple.scheme) and len(url_tuple.scheme) > 1
-
-
 def win_exe_ext():
     return ".exe"
 
 
-def path_to_os_path(*pths):
-    """
-    Takes an arbitrary number of positional parameters
-    converts each arguemnt of type string to use a normalized
-    filepath separator, and returns a list of all values
-    """
-    ret_pths = []
-    for pth in pths:
-        if isinstance(pth, str) and not is_path_url(pth):
-            pth = convert_to_platform_path(pth)
-        ret_pths.append(pth)
-    return ret_pths
-
-
 def sanitize_filename(filename: str) -> str:
     """
     Replaces unsupported characters (for the host) in a filename with underscores.
@@ -145,42 +123,6 @@ def sanitize_filename(filename: str) -> str:
     return re.sub(r'[\x00-\x1F\x7F"*/:<>?\\|]', "_", filename)
 
 
-def system_path_filter(_func=None, arg_slice=None):
-    """
-    Filters function arguments to account for platform path separators.
-    Optional slicing range can be specified to select specific arguments
-
-    This decorator takes all (or a slice) of a method's positional arguments
-    and normalizes usage of filepath separators on a per platform basis.
-
-    Note: **kwargs, urls, and any type that is not a string are ignored
-    so in such cases where path normalization is required, that should be
-    handled by calling path_to_os_path directly as needed.
-
-    Parameters:
-        arg_slice (slice): a slice object specifying the slice of arguments
-            in the decorated method over which filepath separators are
-            normalized
-    """
-    from functools import wraps
-
-    def holder_func(func):
-        @wraps(func)
-        def path_filter_caller(*args, **kwargs):
-            args = list(args)
-            if arg_slice:
-                args[arg_slice] = path_to_os_path(*args[arg_slice])
-            else:
-                args = path_to_os_path(*args)
-            return func(*args, **kwargs)
-
-        return path_filter_caller
-
-    if _func:
-        return holder_func(_func)
-    return holder_func
-
-
 @memoized
 def get_system_path_max():
     # Choose a conservative default
@@ -202,54 +144,6 @@ def get_system_path_max():
     return sys_max_path_length
 
 
-class Path:
-    """
-    Describes the filepath separator types
-    in an enum style
-    with a helper attribute
-    exposing the path type of
-    the current platform.
-    """
-
-    unix = 0
-    windows = 1
-    platform_path = windows if sys.platform == "win32" else unix
-
-
-def format_os_path(path, mode=Path.unix):
-    """
-    Format path to use consistent, platform specific
-    separators. Absolute paths are converted between
-    drive letters and a prepended '/' as per platform
-    requirement.
-
-    Parameters:
-        path (str): the path to be normalized, must be a string
-            or expose the replace method.
-        mode (Path): the path filesperator style to normalize the
-            passed path to. Default is unix style, i.e. '/'
-    """
-    if not path:
-        return path
-    if mode == Path.windows:
-        path = path.replace("/", "\\")
-    else:
-        path = path.replace("\\", "/")
-    return path
-
-
-def convert_to_posix_path(path):
-    return format_os_path(path, mode=Path.unix)
-
-
-def convert_to_windows_path(path):
-    return format_os_path(path, mode=Path.windows)
-
-
-def convert_to_platform_path(path):
-    return format_os_path(path, mode=Path.platform_path)
-
-
 def substitute_config_variables(path):
     """Substitute placeholders into paths.
 
diff --git a/lib/spack/spack/util/string.py b/lib/spack/spack/util/string.py
deleted file mode 100644
index 03dc2bb850..0000000000
--- a/lib/spack/spack/util/string.py
+++ /dev/null
@@ -1,57 +0,0 @@
-# Copyright 2013-2023 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-
-def comma_list(sequence, article=""):
-    if type(sequence) is not list:
-        sequence = list(sequence)
-
-    if not sequence:
-        return
-    elif len(sequence) == 1:
-        return sequence[0]
-    else:
-        out = ", ".join(str(s) for s in sequence[:-1])
-        if len(sequence) != 2:
-            out += ","  # oxford comma
-        out += " "
-        if article:
-            out += article + " "
-        out += str(sequence[-1])
-        return out
-
-
-def comma_or(sequence):
-    return comma_list(sequence, "or")
-
-
-def comma_and(sequence):
-    return comma_list(sequence, "and")
-
-
-def quote(sequence, q="'"):
-    return ["%s%s%s" % (q, e, q) for e in sequence]
-
-
-def plural(n, singular, plural=None, show_n=True):
-    """Pluralize <singular> word by adding an s if n != 1.
-
-    Arguments:
-        n (int): number of things there are
-        singular (str): singular form of word
-        plural (str or None): optional plural form, for when it's not just
-            singular + 's'
-        show_n (bool): whether to include n in the result string (default True)
-
-    Returns:
-        (str): "1 thing" if n == 1 or "n things" if n != 1
-    """
-    number = "%s " % n if show_n else ""
-    if n == 1:
-        return "%s%s" % (number, singular)
-    elif plural is not None:
-        return "%s%s" % (number, plural)
-    else:
-        return "%s%ss" % (number, singular)
diff --git a/lib/spack/spack/util/url.py b/lib/spack/spack/util/url.py
index 9b3c55f332..0644a17ada 100644
--- a/lib/spack/spack/util/url.py
+++ b/lib/spack/spack/util/url.py
@@ -14,7 +14,9 @@ import sys
 import urllib.parse
 import urllib.request
 
-from spack.util.path import convert_to_posix_path, sanitize_filename
+from llnl.path import convert_to_posix_path
+
+from spack.util.path import sanitize_filename
 
 
 def validate_scheme(scheme):
diff --git a/lib/spack/spack/variant.py b/lib/spack/spack/variant.py
index e0b9a5540b..7b045d6262 100644
--- a/lib/spack/spack/variant.py
+++ b/lib/spack/spack/variant.py
@@ -15,10 +15,10 @@ import re
 
 import llnl.util.lang as lang
 import llnl.util.tty.color
+from llnl.string import comma_or
 
 import spack.directives
 import spack.error as error
-from spack.util.string import comma_or
 
 special_variant_values = [None, "none", "*"]