工作中，我们用了 uv 来管理 Python 项目，可以快速安装依赖和固定子依赖的版本信息。 我在一段时间的休假回来后例行更新电脑上的包库，发现 uv 有了新版本，于是我就更新了 uv。 结果在一个项目中更新 uv.lock 文件后发现有很多依赖的 wheels 从锁文件中消失了。 比如如下配置的 pyproject.toml 文件：

[project]
name = "demo"
version = "0.1.0"
readme = "README.md"

dependencies = [
    "pymongo==4.10.0",
]

requires-python = "==3.12"

在新版本升级 pymongo 版本后 wheels 都消失了：

 [[package]]
 name = "pymongo"
-version = "4.8.0"
+version = "4.10.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "dnspython" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/05/2c/ad0896cb94668c3cad1eb702ab60ae17036b051f54cfe547f11a0322f1d3/pymongo-4.8.0.tar.gz", hash = "sha256:454f2295875744dc70f1881e4b2eb99cdad008a33574bc8aaf120530f66c0cde", size = 1506091 }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/9e/8d/b082d026f96215a76553032620549f931679da7f941018e2c358fd549faa/pymongo-4.8.0-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:e6a720a3d22b54183352dc65f08cd1547204d263e0651b213a0a2e577e838526", size = 699090 },
-    { url = "https://files.pythonhosted.org/packages/eb/da/fa51bb7d8d5c8b4672b72c05a9357b5f9300f48128574c746fa4825f607a/pymongo-4.8.0-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:31e4d21201bdf15064cf47ce7b74722d3e1aea2597c6785882244a3bb58c7eab", size = 698800 },
-    { url = "https://files.pythonhosted.org/packages/7b/dc/78f0c931d38bece6ae1dc49035961c82f3eb42952c745391ebdd3a910222/pymongo-4.8.0-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:c6b804bb4f2d9dc389cc9e827d579fa327272cdb0629a99bfe5b83cb3e269ebf", size = 1655527 },
-    { url = "https://files.pythonhosted.org/packages/74/36/92f0eeeb5111c332072e37efb1d5a668c5e4b75be53cbd06a77f6b4192d2/pymongo-4.8.0-cp312-cp312-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl", hash = "sha256:f2fbdb87fe5075c8beb17a5c16348a1ea3c8b282a5cb72d173330be2fecf22f5", size = 1718203 },
-    { url = "https://files.pythonhosted.org/packages/98/40/757579f837dadaddf167cd36ae85a7ab29c035bc0ae8d90bdc8a5fbdfc33/pymongo-4.8.0-cp312-cp312-manylinux_2_17_s390x.manylinux2014_s390x.whl", hash = "sha256:cd39455b7ee70aabee46f7399b32ab38b86b236c069ae559e22be6b46b2bbfc4", size = 1685776 },
-    { url = "https://files.pythonhosted.org/packages/24/bb/13d23966ad01511610a471eae480bcb6a94b832c40f2bdbc706f7a757b76/pymongo-4.8.0-cp312-cp312-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:940d456774b17814bac5ea7fc28188c7a1338d4a233efbb6ba01de957bded2e8", size = 1650569 },
-    { url = "https://files.pythonhosted.org/packages/b5/80/1f405ce80cb6a3867709147e24a2f69e342ff71fb1b9ba663d0237f0c5ed/pymongo-4.8.0-cp312-cp312-manylinux_2_5_i686.manylinux1_i686.manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:236bbd7d0aef62e64caf4b24ca200f8c8670d1a6f5ea828c39eccdae423bc2b2", size = 1601592 },
-    { url = "https://files.pythonhosted.org/packages/30/19/cd66230b6407c6b8cf45c1ae073659a88af5699c792c46fd4eaf317bd11e/pymongo-4.8.0-cp312-cp312-win32.whl", hash = "sha256:47ec8c3f0a7b2212dbc9be08d3bf17bc89abd211901093e3ef3f2adea7de7a69", size = 656042 },
-    { url = "https://files.pythonhosted.org/packages/99/1c/f5108dc39450077556844abfd92b768c57775f85270fc0b1dc834ad18113/pymongo-4.8.0-cp312-cp312-win_amd64.whl", hash = "sha256:e84bc7707492f06fbc37a9f215374d2977d21b72e10a67f1b31893ec5a140ad8", size = 680400 },
-]
+sdist = { url = "https://files.pythonhosted.org/packages/31/8a/324251afdeab2ea5ff94dc84b8d310b389edfaa49074f677d74833e06d03/pymongo-4.10.0.tar.gz", hash = "sha256:2b56e499e0066c4a21a26b451b10377f147c360aa318f49f8c640b7f588e8e8c", size = 1896136 }

从最近一段时间的 uv release 找到了关联的 PR astral-sh/uv#7904。 uv 为了简化 uv.lock 文件的体积，会自动忽略无关的 Python 版本 wheels。 看上去很合理，但也确实是从这个版本开始的。 于是就提了个 issue astral-sh/uv#8169。 在和项目维护者沟通后才了解到 Python 版本号 x.y 实际上是 x.y.0 的简写。 这个行为是 Version specifiers 中定义的，但我并没有注意到这个细节。

实际上在原文 L224-L227 中有明确说明：

``X.Y`` and ``X.Y.0`` are not considered distinct release numbers, as
the release segment comparison rules implicit expand the two component
form to ``X.Y.0`` when comparing it to any release segment that includes
three components.

所以正确的写法应该是 requires-python = "==3.12.*"。