Add note on comparison with other Git libraries (#1501)

Cargo.lock

@@ -35,9 +35,9 @@ checksum = "b248f5224d1d606005e02c97f5aa4e88eeb230488bcc03bc9ca4d7991399f2b5"
 
 [[package]]
 name = "libc"
-version = "0.2.164"
+version = "0.2.170"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "433bfe06b8c75da9b2e3fbea6e5329ff87748f0b144ef75306e674c3f6f7c13f"
+checksum = "875b3680cb2f8f71bdcf9a30f38d48282f5d3c95cbf9b3fa57269bb5d5c06828"
 
 [[package]]
 name = "memchr"
@@ -64,9 +64,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.20.2"
+version = "1.20.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
+checksum = "945462a4b81e43c4e3ba96bd7b49d834c6f61198356aa858733bc4acf3cbe62e"
 
 [[package]]
 name = "pack-py"
@@ -78,24 +78,24 @@ dependencies = [
 
 [[package]]
 name = "portable-atomic"
-version = "1.9.0"
+version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc9c68a3f6da06753e9335d63e27f6b9754dd1920d941135b7ea8224f141adb2"
+checksum = "350e9b48cbc6b0e028b0473b114454c6316e57336ee184ceab6e53f72c178b3e"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.89"
+version = "1.0.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f139b0662de085916d1fb67d2b4169d1addddda1919e696f3252b740b629986e"
+checksum = "60946a68e5f9d28b0dc1c21bb8a97ee7d018a8b322fa57838ba31cc878e22d99"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "pyo3"
-version = "0.23.4"
+version = "0.23.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "57fe09249128b3173d092de9523eaa75136bf7ba85e0d69eca241c7939c933cc"
+checksum = "7778bffd85cf38175ac1f545509665d0b9b92a198ca7941f131f85f7a4f9a872"
 dependencies = [
  "cfg-if",
  "indoc",
@@ -111,9 +111,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-build-config"
-version = "0.23.4"
+version = "0.23.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cd3927b5a78757a0d71aa9dff669f903b1eb64b54142a9bd9f757f8fde65fd7"
+checksum = "94f6cbe86ef3bf18998d9df6e0f3fc1050a8c5efa409bf712e661a4366e010fb"
 dependencies = [
  "once_cell",
  "target-lexicon",
@@ -121,9 +121,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-ffi"
-version = "0.23.4"
+version = "0.23.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dab6bb2102bd8f991e7749f130a70d05dd557613e39ed2deeee8e9ca0c4d548d"
+checksum = "e9f1b4c431c0bb1c8fb0a338709859eed0d030ff6daa34368d3b152a63dfdd8d"
 dependencies = [
  "libc",
  "pyo3-build-config",
@@ -131,9 +131,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros"
-version = "0.23.4"
+version = "0.23.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91871864b353fd5ffcb3f91f2f703a22a9797c91b9ab497b1acac7b07ae509c7"
+checksum = "fbc2201328f63c4710f68abdf653c89d8dbc2858b88c5d88b0ff38a75288a9da"
 dependencies = [
  "proc-macro2",
  "pyo3-macros-backend",
@@ -143,9 +143,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros-backend"
-version = "0.23.4"
+version = "0.23.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "43abc3b80bc20f3facd86cd3c60beed58c3e2aa26213f3cda368de39c60a27e4"
+checksum = "fca6726ad0f3da9c9de093d6f116a93c1a38e417ed73bf138472cf4064f72028"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -156,18 +156,18 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.37"
+version = "1.0.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
+checksum = "0e4dccaaaf89514f546c693ddc140f729f958c247918a13380cccc6078391acc"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
 name = "syn"
-version = "2.0.87"
+version = "2.0.98"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25aa4ce346d03a6dcd68dd8b4010bcb74e54e62c90c573f394c46eae99aba32d"
+checksum = "36147f1a48ae0ec2b5b3bc5b537d267457555a10dc06f3dbc8cb11ba3006d3b1"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -182,9 +182,9 @@ checksum = "61c41af27dd6d1e27b1b16b489db798443478cef1f06a660c96db617ba5de3b1"
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.13"
+version = "1.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
+checksum = "00e2473a93778eb0bad35909dff6a10d28e63f792f16ed15e404fca9d5eeedbe"
 
 [[package]]
 name = "unindent"

README.rst

@@ -15,6 +15,20 @@ SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 The project is named after the part of London that Mr. and Mrs. Git live in
 the particular Monty Python sketch.
 
+Differences with other Python Git libraries
+-------------------------------------------
+
+Unlike other Python Git libraries, Dulwich is available as a standalone
+package that doesn't depend on git (like GitPython) being installed or any
+native code (like pygit2).
+
+This comes at the cost of speed, but makes it easier to deploy in environments
+where git isn't available or where it's important to have a pure Python
+implementation.
+
+To improve performance, Dulwich includes optional Rust bindings that can be
+used to speed up low-level operations.
+
 Installation
 ------------
 

dulwich/object_store.py

@@ -1419,14 +1419,22 @@ class MissingObjectFinder:
 
 
 class ObjectStoreGraphWalker:
-    """Graph walker that finds what commits are missing from an object store.
+    """Graph walker that finds what commits are missing from an object store."""
 
-    Attributes:
-      heads: Revisions without descendants in the local repo
-      get_parents: Function to retrieve parents in the local repo
-    """
+    heads: set[ObjectID]
+    """Revisions without descendants in the local repo."""
+
+    get_parents: Callable[[ObjectID], ObjectID]
+    """Function to retrieve parents in the local repo."""
+
+    shallow: set[ObjectID]
 
-    def __init__(self, local_heads, get_parents, shallow=None) -> None:
+    def __init__(
+        self,
+        local_heads: Iterable[ObjectID],
+        get_parents,
+        shallow: Optional[set[ObjectID]] = None,
+    ) -> None:
         """Create a new instance.
 
         Args:
@@ -1443,7 +1451,7 @@ class ObjectStoreGraphWalker:
     def nak(self) -> None:
         """Nothing in common was found."""
 
-    def ack(self, sha) -> None:
+    def ack(self, sha: ObjectID) -> None:
         """Ack that a revision and its ancestors are present in the source."""
         if len(sha) != 40:
             raise ValueError(f"unexpected sha {sha!r} received")