From 6f950b0110a55af747399ed49f28c843cd6b4a68 Mon Sep 17 00:00:00 2001
From: JSKenyon <jonathan.simon.kenyon@gmail.com>
Date: Tue, 26 Mar 2024 15:01:11 +0200
Subject: [PATCH 1/6] Checkpoint work so far.

---
 pyproject.toml            |  1 +
 scabha/basetypes.py       | 72 ++++++++++++++++++++++++++++++++++++---
 stimela/backends/utils.py | 10 +++---
 3 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 7febb0e1..8bab874a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,6 +24,7 @@ pydantic = "^1.10.2"
 psutil = "^5.9.3"
 rich = "^13.7.0"
 dill = "^0.3.6"
+typeguard = "^4.2.1"
 
 [tool.poetry.scripts]
 stimela = "stimela.main:cli"
diff --git a/scabha/basetypes.py b/scabha/basetypes.py
index fa8c438c..23eb16bc 100644
--- a/scabha/basetypes.py
+++ b/scabha/basetypes.py
@@ -1,9 +1,12 @@
 from dataclasses import field, dataclass
 from collections import OrderedDict
-from typing import List
+from typing import List, Union, get_args, get_origin
 import os.path
 import re
 from .exceptions import UnsetError
+from itertools import zip_longest
+from typeguard import check_type, TypeCheckError
+
 
 def EmptyDictDefault():
     return field(default_factory=lambda:OrderedDict())
@@ -55,7 +58,7 @@ def __init__(self, value):
     def parse(value: str, expand_user=True):
         """
         Parses URI. If URI does not start with "protocol://", assumes "file://"
-        
+
         Returns tuple of (protocol, path, is_remote)
 
         If expand_user is True, ~ in (file-protocol) paths will be expanded.
@@ -75,7 +78,7 @@ class File(URI):
     @property
     def NAME(self):
         return File(os.path.basename(self))
-    
+
     @property
     def PATH(self):
         return File(os.path.abspath(self))
@@ -95,7 +98,7 @@ def BASENAME(self):
     @property
     def EXT(self):
         return os.path.splitext(self)[1]
-    
+
     @property
     def EXISTS(self):
         return os.path.exists(self)
@@ -114,3 +117,64 @@ def is_file_type(dtype):
 def is_file_list_type(dtype):
     return any(dtype == List[t] for t in FILE_TYPES)
 
+
+class Skip(object):
+    def iterate_samples(self, collection):
+        return ()
+
+
+def get_filelikes(dtype, value, filelikes=None):
+    """Recursively recover all filelike elements from a composite dtype."""
+
+    filelikes = set() if filelikes is None else filelikes
+
+    origin = get_origin(dtype)
+    args = get_args(dtype)
+
+    if origin:  # Implies composition.
+
+        if origin is dict:
+
+            # No further work required for empty collections.
+            if len(value) == 0:
+                return filelikes
+
+            k_dtype, v_dtype = args
+
+            for k, v in value.items():
+                filelikes = get_filelikes(k_dtype, k, filelikes)
+                filelikes = get_filelikes(v_dtype, v, filelikes)
+
+        elif origin in (tuple, list, set):
+
+            # No further work required for empty collections.
+            if len(value) == 0:
+                return filelikes
+
+            # This is a special case for tuples of arbitrary
+            # length i.e. list-like behaviour.
+            if ... in args:
+                args = tuple([a for a in args if a != ...])
+
+            for dt, v in zip_longest(args, value, fillvalue=args[0]):
+                filelikes = get_filelikes(dt, v, filelikes)
+
+        elif origin is Union:
+
+            for dt in args:
+
+                try:
+                    # Do not check collection member types. 
+                    check_type(value, dt, collection_check_strategy=Skip())
+                except TypeCheckError:
+                    continue
+                filelikes = get_filelikes(dt, value, filelikes)
+
+        else:
+            raise ValueError(f"Failed to traverse {dtype} dtype when looking for files.")
+
+    else:
+        if is_file_type(dtype):
+            filelikes.add(value)
+
+    return filelikes
diff --git a/stimela/backends/utils.py b/stimela/backends/utils.py
index 2dbe5124..accf5aee 100644
--- a/stimela/backends/utils.py
+++ b/stimela/backends/utils.py
@@ -4,7 +4,7 @@
 from stimela.kitchen.cab import Cab, Parameter
 from scabha.exceptions import SchemaError
 from stimela.exceptions import BackendError
-from scabha.basetypes import File, Directory, MS, URI
+from scabha.basetypes import File, Directory, MS, URI, get_filelikes
 
 ## commenting out for now -- will need to fix when we reactive the kube backend (and have tests for it)
 
@@ -34,11 +34,9 @@ def add_target(param_name, path, must_exist, readwrite):
         if schema is None:
             raise SchemaError(f"parameter {name} not in defined inputs or outputs for this cab. This should have been caught by validation earlier!")
 
-        if schema.is_file_type:
-            files = [value]
-        elif schema.is_file_list_type:
-            files = value
-        else:
+        files = get_filelikes(schema._dtype, value)
+
+        if not files:
             continue
 
         must_exist = schema.must_exist and name in inputs 

From 2c4a9b8998f941b8d2b221491c4a84f6d09f573a Mon Sep 17 00:00:00 2001
From: JSKenyon <jonathan.simon.kenyon@gmail.com>
Date: Tue, 26 Mar 2024 16:37:20 +0200
Subject: [PATCH 2/6] Add tests and refine approach.

---
 scabha/basetypes.py                  | 36 ++++++++++++++++--------
 tests/scabha_tests/test_filelikes.py | 42 ++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 12 deletions(-)
 create mode 100644 tests/scabha_tests/test_filelikes.py

diff --git a/scabha/basetypes.py b/scabha/basetypes.py
index 23eb16bc..f541dd4b 100644
--- a/scabha/basetypes.py
+++ b/scabha/basetypes.py
@@ -1,11 +1,15 @@
+from __future__ import annotations
 from dataclasses import field, dataclass
 from collections import OrderedDict
-from typing import List, Union, get_args, get_origin
+from typing import List, Union, get_args, get_origin, Any
 import os.path
 import re
 from .exceptions import UnsetError
 from itertools import zip_longest
-from typeguard import check_type, TypeCheckError
+from typeguard import (
+    check_type, TypeCheckError, TypeCheckerCallable, TypeCheckMemo, checker_lookup_functions
+)
+from inspect import isclass
 
 
 def EmptyDictDefault():
@@ -118,11 +122,21 @@ def is_file_list_type(dtype):
     return any(dtype == List[t] for t in FILE_TYPES)
 
 
-class Skip(object):
-    def iterate_samples(self, collection):
-        return ()
+def check_filelike(value: Any, origin_type: Any, args: tuple[Any, ...], memo: TypeCheckMemo) -> None:
+    """Custom checker for filelike objects. Currently checks for strings."""
+    if not isinstance(value, str):
+        raise TypeCheckError(f'{value} is not compatible with URI or its subclasses.')
 
 
+def filelike_lookup(origin_type: Any, args: tuple[Any, ...], extras: tuple[Any, ...]) -> TypeCheckerCallable | None:
+    """Lookup the custom checker for filelike objects."""
+    if isclass(origin_type) and issubclass(origin_type, URI):
+        return check_filelike
+
+    return None
+
+checker_lookup_functions.append(filelike_lookup)  # Register custom type checker.
+
 def get_filelikes(dtype, value, filelikes=None):
     """Recursively recover all filelike elements from a composite dtype."""
 
@@ -152,9 +166,9 @@ def get_filelikes(dtype, value, filelikes=None):
                 return filelikes
 
             # This is a special case for tuples of arbitrary
-            # length i.e. list-like behaviour.
-            if ... in args:
-                args = tuple([a for a in args if a != ...])
+            # length i.e. list-like behaviour. We can simply 
+            # strip out the Ellipsis.
+            args = tuple([arg for arg in args if arg != ...])
 
             for dt, v in zip_longest(args, value, fillvalue=args[0]):
                 filelikes = get_filelikes(dt, v, filelikes)
@@ -162,11 +176,9 @@ def get_filelikes(dtype, value, filelikes=None):
         elif origin is Union:
 
             for dt in args:
-
                 try:
-                    # Do not check collection member types. 
-                    check_type(value, dt, collection_check_strategy=Skip())
-                except TypeCheckError:
+                    check_type(value, dt)
+                except TypeCheckError:  # Value doesn't match dtype - incorrect branch.
                     continue
                 filelikes = get_filelikes(dt, value, filelikes)
 
diff --git a/tests/scabha_tests/test_filelikes.py b/tests/scabha_tests/test_filelikes.py
new file mode 100644
index 00000000..b3697d92
--- /dev/null
+++ b/tests/scabha_tests/test_filelikes.py
@@ -0,0 +1,42 @@
+from scabha.basetypes import get_filelikes, File, URI, Directory, MS
+from typing import Dict, List, Set, Tuple, Union, Optional
+import pytest
+
+
+@pytest.fixture(scope="module", params=[File, URI, Directory, MS])
+def templates(request):
+    
+    ft = request.param
+    
+    TEMPLATES = (
+        (Tuple, (), set()),
+        (Tuple[int, ...], [1, 2], set()),
+        (Tuple[ft, ...], ("foo", "bar"), {"foo", "bar"}),
+        (Tuple[ft, str], ("foo", "bar"), {"foo"}),
+        (Dict[str, int], {"a": 1, "b": 2}, set()),
+        (Dict[str, ft], {"a": "foo", "b": "bar"}, {"foo", "bar"}),
+        (Dict[ft, str], {"foo": "a", "bar": "b"}, {"foo", "bar"}),
+        (List[ft], [], set()),
+        (List[int], [1, 2], set()),
+        (List[ft], ["foo", "bar"], {"foo", "bar"}),
+        (Set[ft], set(), set()),
+        (Set[int], {1, 2}, set()),
+        (Set[ft], {"foo", "bar"}, {"foo", "bar"}),
+        (Union[str, List[ft]], "foo", set()),
+        (Union[str, List[ft]], ["foo"], {"foo"}),
+        (Union[str, Tuple[ft]], "foo", set()),
+        (Union[str, Tuple[ft]], ("foo",), {"foo"}),
+        (Optional[ft], None, set()),
+        (Optional[ft], "foo", {"foo"}),
+        (Optional[Union[ft, int]], 1, set()),
+        (Optional[Union[ft, int]], "foo", {"foo"}),
+        (Dict[str, Tuple[ft, str]], {"a": ("foo", "bar")}, {"foo"})
+    )
+
+    return TEMPLATES
+
+
+def test_get_filelikes(templates):
+
+    for dt, v, res in templates:
+        assert get_filelikes(dt, v) == res, f"Failed for dtype {dt} and value {v}."

From afe569efffd67c6431efc0825ba170a61f6f5ffb Mon Sep 17 00:00:00 2001
From: JSKenyon <jonathan.simon.kenyon@gmail.com>
Date: Tue, 26 Mar 2024 15:01:11 +0200
Subject: [PATCH 3/6] Checkpoint work so far.

---
 pyproject.toml            |  1 +
 scabha/basetypes.py       | 72 ++++++++++++++++++++++++++++++++++++---
 stimela/backends/utils.py | 10 +++---
 3 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 306a7a52..2da49782 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,6 +24,7 @@ pydantic = "^1.10.2"
 psutil = "^5.9.3"
 rich = "^13.7.0"
 dill = "^0.3.6"
+typeguard = "^4.2.1"
 
 [tool.poetry.scripts]
 stimela = "stimela.main:cli"
diff --git a/scabha/basetypes.py b/scabha/basetypes.py
index fa8c438c..23eb16bc 100644
--- a/scabha/basetypes.py
+++ b/scabha/basetypes.py
@@ -1,9 +1,12 @@
 from dataclasses import field, dataclass
 from collections import OrderedDict
-from typing import List
+from typing import List, Union, get_args, get_origin
 import os.path
 import re
 from .exceptions import UnsetError
+from itertools import zip_longest
+from typeguard import check_type, TypeCheckError
+
 
 def EmptyDictDefault():
     return field(default_factory=lambda:OrderedDict())
@@ -55,7 +58,7 @@ def __init__(self, value):
     def parse(value: str, expand_user=True):
         """
         Parses URI. If URI does not start with "protocol://", assumes "file://"
-        
+
         Returns tuple of (protocol, path, is_remote)
 
         If expand_user is True, ~ in (file-protocol) paths will be expanded.
@@ -75,7 +78,7 @@ class File(URI):
     @property
     def NAME(self):
         return File(os.path.basename(self))
-    
+
     @property
     def PATH(self):
         return File(os.path.abspath(self))
@@ -95,7 +98,7 @@ def BASENAME(self):
     @property
     def EXT(self):
         return os.path.splitext(self)[1]
-    
+
     @property
     def EXISTS(self):
         return os.path.exists(self)
@@ -114,3 +117,64 @@ def is_file_type(dtype):
 def is_file_list_type(dtype):
     return any(dtype == List[t] for t in FILE_TYPES)
 
+
+class Skip(object):
+    def iterate_samples(self, collection):
+        return ()
+
+
+def get_filelikes(dtype, value, filelikes=None):
+    """Recursively recover all filelike elements from a composite dtype."""
+
+    filelikes = set() if filelikes is None else filelikes
+
+    origin = get_origin(dtype)
+    args = get_args(dtype)
+
+    if origin:  # Implies composition.
+
+        if origin is dict:
+
+            # No further work required for empty collections.
+            if len(value) == 0:
+                return filelikes
+
+            k_dtype, v_dtype = args
+
+            for k, v in value.items():
+                filelikes = get_filelikes(k_dtype, k, filelikes)
+                filelikes = get_filelikes(v_dtype, v, filelikes)
+
+        elif origin in (tuple, list, set):
+
+            # No further work required for empty collections.
+            if len(value) == 0:
+                return filelikes
+
+            # This is a special case for tuples of arbitrary
+            # length i.e. list-like behaviour.
+            if ... in args:
+                args = tuple([a for a in args if a != ...])
+
+            for dt, v in zip_longest(args, value, fillvalue=args[0]):
+                filelikes = get_filelikes(dt, v, filelikes)
+
+        elif origin is Union:
+
+            for dt in args:
+
+                try:
+                    # Do not check collection member types. 
+                    check_type(value, dt, collection_check_strategy=Skip())
+                except TypeCheckError:
+                    continue
+                filelikes = get_filelikes(dt, value, filelikes)
+
+        else:
+            raise ValueError(f"Failed to traverse {dtype} dtype when looking for files.")
+
+    else:
+        if is_file_type(dtype):
+            filelikes.add(value)
+
+    return filelikes
diff --git a/stimela/backends/utils.py b/stimela/backends/utils.py
index 2dbe5124..accf5aee 100644
--- a/stimela/backends/utils.py
+++ b/stimela/backends/utils.py
@@ -4,7 +4,7 @@
 from stimela.kitchen.cab import Cab, Parameter
 from scabha.exceptions import SchemaError
 from stimela.exceptions import BackendError
-from scabha.basetypes import File, Directory, MS, URI
+from scabha.basetypes import File, Directory, MS, URI, get_filelikes
 
 ## commenting out for now -- will need to fix when we reactive the kube backend (and have tests for it)
 
@@ -34,11 +34,9 @@ def add_target(param_name, path, must_exist, readwrite):
         if schema is None:
             raise SchemaError(f"parameter {name} not in defined inputs or outputs for this cab. This should have been caught by validation earlier!")
 
-        if schema.is_file_type:
-            files = [value]
-        elif schema.is_file_list_type:
-            files = value
-        else:
+        files = get_filelikes(schema._dtype, value)
+
+        if not files:
             continue
 
         must_exist = schema.must_exist and name in inputs 

From 9e574eac8e53f90b13914774f8eeda5f925f2ce9 Mon Sep 17 00:00:00 2001
From: JSKenyon <jonathan.simon.kenyon@gmail.com>
Date: Tue, 26 Mar 2024 16:37:20 +0200
Subject: [PATCH 4/6] Add tests and refine approach.

---
 scabha/basetypes.py                  | 36 ++++++++++++++++--------
 tests/scabha_tests/test_filelikes.py | 42 ++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 12 deletions(-)
 create mode 100644 tests/scabha_tests/test_filelikes.py

diff --git a/scabha/basetypes.py b/scabha/basetypes.py
index 23eb16bc..f541dd4b 100644
--- a/scabha/basetypes.py
+++ b/scabha/basetypes.py
@@ -1,11 +1,15 @@
+from __future__ import annotations
 from dataclasses import field, dataclass
 from collections import OrderedDict
-from typing import List, Union, get_args, get_origin
+from typing import List, Union, get_args, get_origin, Any
 import os.path
 import re
 from .exceptions import UnsetError
 from itertools import zip_longest
-from typeguard import check_type, TypeCheckError
+from typeguard import (
+    check_type, TypeCheckError, TypeCheckerCallable, TypeCheckMemo, checker_lookup_functions
+)
+from inspect import isclass
 
 
 def EmptyDictDefault():
@@ -118,11 +122,21 @@ def is_file_list_type(dtype):
     return any(dtype == List[t] for t in FILE_TYPES)
 
 
-class Skip(object):
-    def iterate_samples(self, collection):
-        return ()
+def check_filelike(value: Any, origin_type: Any, args: tuple[Any, ...], memo: TypeCheckMemo) -> None:
+    """Custom checker for filelike objects. Currently checks for strings."""
+    if not isinstance(value, str):
+        raise TypeCheckError(f'{value} is not compatible with URI or its subclasses.')
 
 
+def filelike_lookup(origin_type: Any, args: tuple[Any, ...], extras: tuple[Any, ...]) -> TypeCheckerCallable | None:
+    """Lookup the custom checker for filelike objects."""
+    if isclass(origin_type) and issubclass(origin_type, URI):
+        return check_filelike
+
+    return None
+
+checker_lookup_functions.append(filelike_lookup)  # Register custom type checker.
+
 def get_filelikes(dtype, value, filelikes=None):
     """Recursively recover all filelike elements from a composite dtype."""
 
@@ -152,9 +166,9 @@ def get_filelikes(dtype, value, filelikes=None):
                 return filelikes
 
             # This is a special case for tuples of arbitrary
-            # length i.e. list-like behaviour.
-            if ... in args:
-                args = tuple([a for a in args if a != ...])
+            # length i.e. list-like behaviour. We can simply 
+            # strip out the Ellipsis.
+            args = tuple([arg for arg in args if arg != ...])
 
             for dt, v in zip_longest(args, value, fillvalue=args[0]):
                 filelikes = get_filelikes(dt, v, filelikes)
@@ -162,11 +176,9 @@ def get_filelikes(dtype, value, filelikes=None):
         elif origin is Union:
 
             for dt in args:
-
                 try:
-                    # Do not check collection member types. 
-                    check_type(value, dt, collection_check_strategy=Skip())
-                except TypeCheckError:
+                    check_type(value, dt)
+                except TypeCheckError:  # Value doesn't match dtype - incorrect branch.
                     continue
                 filelikes = get_filelikes(dt, value, filelikes)
 
diff --git a/tests/scabha_tests/test_filelikes.py b/tests/scabha_tests/test_filelikes.py
new file mode 100644
index 00000000..b3697d92
--- /dev/null
+++ b/tests/scabha_tests/test_filelikes.py
@@ -0,0 +1,42 @@
+from scabha.basetypes import get_filelikes, File, URI, Directory, MS
+from typing import Dict, List, Set, Tuple, Union, Optional
+import pytest
+
+
+@pytest.fixture(scope="module", params=[File, URI, Directory, MS])
+def templates(request):
+    
+    ft = request.param
+    
+    TEMPLATES = (
+        (Tuple, (), set()),
+        (Tuple[int, ...], [1, 2], set()),
+        (Tuple[ft, ...], ("foo", "bar"), {"foo", "bar"}),
+        (Tuple[ft, str], ("foo", "bar"), {"foo"}),
+        (Dict[str, int], {"a": 1, "b": 2}, set()),
+        (Dict[str, ft], {"a": "foo", "b": "bar"}, {"foo", "bar"}),
+        (Dict[ft, str], {"foo": "a", "bar": "b"}, {"foo", "bar"}),
+        (List[ft], [], set()),
+        (List[int], [1, 2], set()),
+        (List[ft], ["foo", "bar"], {"foo", "bar"}),
+        (Set[ft], set(), set()),
+        (Set[int], {1, 2}, set()),
+        (Set[ft], {"foo", "bar"}, {"foo", "bar"}),
+        (Union[str, List[ft]], "foo", set()),
+        (Union[str, List[ft]], ["foo"], {"foo"}),
+        (Union[str, Tuple[ft]], "foo", set()),
+        (Union[str, Tuple[ft]], ("foo",), {"foo"}),
+        (Optional[ft], None, set()),
+        (Optional[ft], "foo", {"foo"}),
+        (Optional[Union[ft, int]], 1, set()),
+        (Optional[Union[ft, int]], "foo", {"foo"}),
+        (Dict[str, Tuple[ft, str]], {"a": ("foo", "bar")}, {"foo"})
+    )
+
+    return TEMPLATES
+
+
+def test_get_filelikes(templates):
+
+    for dt, v, res in templates:
+        assert get_filelikes(dt, v) == res, f"Failed for dtype {dt} and value {v}."

From b3f8ee07753e2f9a4452cdb12aec5325a76793fe Mon Sep 17 00:00:00 2001
From: Oleg Smirnov <osmirnov@gmail.com>
Date: Wed, 27 Mar 2024 11:30:32 +0200
Subject: [PATCH 5/6] added backend.singularity.bind_dirs option

---
 stimela/backends/singularity.py | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/stimela/backends/singularity.py b/stimela/backends/singularity.py
index 54d515e7..79d1a8cc 100644
--- a/stimela/backends/singularity.py
+++ b/stimela/backends/singularity.py
@@ -1,15 +1,14 @@
 import subprocess
 import os
-import re
 import logging
-from stimela import utils
+from enum import Enum
 import stimela
 from shutil import which
 from dataclasses import dataclass
 from omegaconf import OmegaConf
 from typing import Dict, List, Any, Optional, Callable
 from contextlib import ExitStack
-from scabha.basetypes import EmptyListDefault
+from scabha.basetypes import EmptyDictDefault
 import datetime
 from stimela.utils.xrun_asyncio import xrun
 
@@ -17,6 +16,9 @@
 
 from . import native
 
+ReadWriteMode = Enum("ReadWriteMode", "ro rw", module=__name__)
+
+
 @dataclass
 class SingularityBackendOptions(object):
     enable: bool = True
@@ -26,6 +28,8 @@ class SingularityBackendOptions(object):
     executable: Optional[str] = None
     remote_only: bool = False      # if True, won't look for singularity on local system -- useful in combination with slurm wrapper
 
+    # optional extra bindings
+    bind_dirs: Dict[str, ReadWriteMode] = EmptyDictDefault()
     # @dataclass
     # class EmptyVolume(object):
     #     name: str
@@ -250,6 +254,10 @@ def run(cab: 'stimela.kitchen.cab.Cab', params: Dict[str, Any], fqname: str,
     
     # initial set of mounts has cwd as read-write
     mounts = {cwd: True}
+    # add extra binds
+    for path, rw in backend.singularity.bind_dirs.items():
+        mounts[path] = mounts.get(path, False) or (rw == ReadWriteMode.rw)
+
     # get extra required filesystem bindings
     resolve_required_mounts(mounts, params, cab.inputs, cab.outputs)
 

From f3ae235a5ca94502087638b8fd26a34aba240302 Mon Sep 17 00:00:00 2001
From: Oleg Smirnov <osmirnov@gmail.com>
Date: Wed, 27 Mar 2024 11:33:04 +0200
Subject: [PATCH 6/6] added ~ support to bind paths

---
 stimela/backends/singularity.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/stimela/backends/singularity.py b/stimela/backends/singularity.py
index 79d1a8cc..97700393 100644
--- a/stimela/backends/singularity.py
+++ b/stimela/backends/singularity.py
@@ -256,6 +256,7 @@ def run(cab: 'stimela.kitchen.cab.Cab', params: Dict[str, Any], fqname: str,
     mounts = {cwd: True}
     # add extra binds
     for path, rw in backend.singularity.bind_dirs.items():
+        path = os.path.expanduser(path)
         mounts[path] = mounts.get(path, False) or (rw == ReadWriteMode.rw)
 
     # get extra required filesystem bindings