Closes #1472: Implement in-memory config backend for config overrides in context manager

docs/config.rst

@@ -15,12 +15,12 @@ The Config types
    :special-members: __contains__, __delitem__, __getitem__, __init__, __iter__, __setitem__
 
 .. autoclass:: pygit2.DefaultConfig
-   :members: add_file, snapshot
+   :members: __enter__, __exit__, add_file, snapshot
    :undoc-members:
    :special-members: __init__
 
 .. autoclass:: pygit2.RepositoryConfig
-   :members: add_file, snapshot
+   :members: __enter__, __exit__, add_file, snapshot
    :undoc-members:
    :special-members: __init__
 

pygit2/_libgit2/ffi.pyi

@@ -22,9 +22,21 @@
 # along with this program; see the file COPYING.  If not, write to
 # the Free Software Foundation, 51 Franklin Street, Fifth Floor,
 # Boston, MA 02110-1301, USA.
-
-from typing import Any, Generic, Literal, NewType, SupportsIndex, TypeVar, overload
-
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import (
+    Any,
+    Generic,
+    Literal,
+    NewType,
+    ParamSpec,
+    SupportsIndex,
+    TypeVar,
+    overload,
+)
+
+P = ParamSpec('P')
 T = TypeVar('T')
 
 NULL_TYPE = NewType('NULL_TYPE', object)
@@ -45,6 +57,11 @@ class int64_t:
 class ssize_t:
     def __getitem__(self, item: Literal[0]) -> int: ...
 
+class uintptr_t:
+    def __int__(self) -> int: ...
+
+class git_config_level_t(int): ...
+
 class _Pointer(Generic[T]):
     def __setitem__(self, item: Literal[0], a: T) -> None: ...
     @overload
@@ -184,15 +201,66 @@ class GitConfigC:
     pass
 
 class GitConfigIteratorC:
-    # incomplete
-    pass
+    backend: 'GitConfigBackendC'
+    flags: int
+    next: Callable[['GitConfigBackendEntryC', GitConfigIteratorC], int]
+    free: Callable[[GitConfigIteratorC], None]
 
 class GitConfigEntryC:
     # incomplete
     name: char_pointer
     value: char_pointer
+    backend_type: char_pointer
+    origin_path: char_pointer
+    include_depth: int
     level: int
 
+class GitConfigBackendEntryC:
+    entry: GitConfigEntryC
+    free: Callable[[GitConfigBackendEntryC], None]
+
+class GitConfigBackendC:
+    version: int
+    readonly: int
+    cfg: GitConfigC
+    open: Callable[[GitConfigBackendC, int, GitRepositoryC], int]
+    get: Callable[
+        [GitConfigBackendC, char_pointer, _Pointer[GitConfigBackendEntryC]], int
+    ]
+    set: Callable[[GitConfigBackendC, char_pointer, char_pointer], int]
+    set_multivar: Callable[
+        [GitConfigBackendC, char_pointer, char_pointer, char_pointer], int
+    ]
+    # this unfortunate name is actually `del`, but that conflicts with a Python keyword
+    del_: Callable[[GitConfigBackendC, char_pointer], int]
+    del_multivar: Callable[[GitConfigBackendC, char_pointer, char_pointer], int]
+    iterator: Callable[[_Pointer[GitConfigIteratorC], GitConfigBackendC], int]
+    snapshot: Callable[[_Pointer[GitConfigBackendC], GitConfigBackendC], int]
+    lock: Callable[[GitConfigBackendC], int]
+    unlock: Callable[[GitConfigBackendC, int], int]
+    free: Callable[[GitConfigBackendC], None]
+
+class GitConfigBackendMemoryOptionsC:
+    version: int
+    backend_type: char_pointer
+    origin_path: char_pointer
+
+class PyGitConfigBackendWrapperC:
+    parent: GitConfigBackendC
+    self: Any
+
+class PyGitConfigBackendEntryC:
+    parent: GitConfigBackendEntryC
+    owner: PyGitConfigBackendWrapperC
+
+class PyGitConfigIteratorWrapperC:
+    parent: GitConfigIteratorC
+    self: Any
+
+class PyGitConfigIteratorEntryC:
+    parent: GitConfigBackendEntryC
+    owner: PyGitConfigIteratorWrapperC
+
 class GitDescribeFormatOptionsC:
     version: int
     abbreviated_size: int
@@ -353,10 +421,41 @@ def new(a: Literal['git_config *']) -> GitConfigC: ...
 @overload
 def new(a: Literal['git_config **']) -> _Pointer[GitConfigC]: ...
 @overload
+def new(a: Literal['git_config_iterator *']) -> GitConfigIteratorC: ...
+@overload
 def new(a: Literal['git_config_iterator **']) -> _Pointer[GitConfigIteratorC]: ...
 @overload
 def new(a: Literal['git_config_entry **']) -> _Pointer[GitConfigEntryC]: ...
 @overload
+def new(a: Literal['git_config_backend *']) -> GitConfigBackendC: ...
+@overload
+def new(a: Literal['git_config_backend **']) -> _Pointer[GitConfigBackendC]: ...
+@overload
+def new(a: Literal['git_config_backend_entry *']) -> GitConfigBackendEntryC: ...
+@overload
+def new(
+    a: Literal['git_config_backend_memory_options *'],
+) -> GitConfigBackendMemoryOptionsC: ...
+@overload
+def new(
+    a: Literal['git_config_level_t[]'],
+    b: list[git_config_level_t],
+) -> list[git_config_level_t]: ...
+@overload
+def new(
+    a: Literal['_pygit_in_memory_backend_entry *'],
+) -> PyGitConfigBackendEntryC: ...
+@overload
+def new(
+    a: Literal['_pygit_in_memory_backend_iterator_entry *'],
+) -> PyGitConfigIteratorEntryC: ...
+@overload
+def new(a: Literal['_pygit_in_memory_backend *']) -> PyGitConfigBackendWrapperC: ...
+@overload
+def new(
+    a: Literal['_pygit_in_memory_backend_iterator *'],
+) -> PyGitConfigIteratorWrapperC: ...
+@overload
 def new(a: Literal['git_describe_format_options *']) -> GitDescribeFormatOptionsC: ...
 @overload
 def new(a: Literal['git_describe_options *']) -> GitDescribeOptionsC: ...
@@ -424,7 +523,12 @@ def new(
 def new(
     a: Literal['char *[]'], b: list[Any]
 ) -> ArrayC[char_pointer]: ...  # For string arrays
+@overload
+def addressof(a: object) -> _Pointer[object]: ...
+@overload
 def addressof(a: object, attribute: str) -> _Pointer[object]: ...
+def def_extern() -> Callable[[Callable[P, T]], Callable[P, T]]: ...
+def from_handle(a: _Pointer[T]) -> T: ...
 def new_handle(a: T) -> _Pointer[T]: ...
 def gc(cdata: T, destructor: Any, size: int = ...) -> T: ...
 
@@ -446,3 +550,42 @@ def cast(a: Literal['size_t'], b: object) -> int: ...
 def cast(a: Literal['ssize_t'], b: object) -> int: ...
 @overload
 def cast(a: Literal['char *'], b: object) -> char_pointer: ...
+@overload
+def cast(a: Literal['uintptr_t'], b: object) -> uintptr_t: ...
+@overload
+def cast(a: Literal['git_config_level_t'], b: int) -> git_config_level_t: ...
+@overload
+def cast(
+    a: Literal['git_config_backend *'],
+    b: PyGitConfigBackendWrapperC,
+) -> GitConfigBackendC: ...
+@overload
+def cast(
+    a: Literal['_pygit_in_memory_backend *'],
+    b: GitConfigBackendC,
+) -> PyGitConfigBackendWrapperC: ...
+@overload
+def cast(
+    a: Literal['git_config_iterator *'],
+    b: PyGitConfigIteratorWrapperC,
+) -> GitConfigIteratorC: ...
+@overload
+def cast(
+    a: Literal['_pygit_in_memory_backend_iterator *'],
+    b: GitConfigIteratorC,
+) -> PyGitConfigIteratorWrapperC: ...
+@overload
+def cast(
+    a: Literal['git_config_backend_entry *'],
+    b: PyGitConfigBackendEntryC | PyGitConfigIteratorEntryC,
+) -> GitConfigBackendEntryC: ...
+@overload
+def cast(
+    a: Literal['_pygit_in_memory_backend_entry *'],
+    b: GitConfigBackendEntryC,
+) -> PyGitConfigBackendEntryC: ...
+@overload
+def cast(
+    a: Literal['_pygit_in_memory_backend_iterator_entry *'],
+    b: GitConfigBackendEntryC,
+) -> PyGitConfigIteratorEntryC: ...

pygit2/_run.py

@@ -68,6 +68,7 @@
     'clone.h',
     'common.h',
     'config.h',
+    'config_bridge.h',
     'describe.h',
     'errors.h',
     'graph.h',
@@ -95,9 +96,10 @@
 
 C_PREAMBLE = """\
 #include <git2.h>
+#include <git2/sys/config.h>
 #include <git2/sys/repository.h>
 #include <git2/sys/filter.h>
-"""
+""" + (dir_path / 'decl' / 'config_bridge.h').read_text(encoding='utf-8')
 
 # ffi
 _, libgit2_kw = get_libgit2_paths()

pygit2/callbacks.py

@@ -564,7 +564,7 @@ def wrapper(*args):
             data._stored_exception = e
             return C.GIT_EUSER
 
-    return ffi.def_extern()(wrapper)  # type: ignore[attr-defined]
+    return ffi.def_extern()(wrapper)  # type: ignore[arg-type]
 
 
 def libgit2_callback_void(f: Callable[P, T]) -> Callable[P, T]:
@@ -584,7 +584,7 @@ def wrapper(*args):
             data._stored_exception = e
             pass  # Function returns void, so we can't do much here.
 
-    return ffi.def_extern()(wrapper)  # type: ignore[attr-defined]
+    return ffi.def_extern()(wrapper)  # type: ignore[arg-type]
 
 
 @libgit2_callback