blocklist the linux cpython builds from 20250517 (#13617)

There is a runtime issue with some of these builds

Here is the testing I've seen (❌ has bug, ✅ works):

* uv version (pbs version)
  * ❌ uv 0.7.7 (pbs 20250521)
  * ❌ uv 0.7.6 (pbs 20250517)
  * ✅ uv 0.7.5 (pbs 20250409)
* os
  * ❌ linux
  * ✅ windows
* arch
  * ❌ x86_64
  * ✅ aarch64
* python version
  * ❌ 3.12
  * ❌ 3.13
  * ❌ 3.14

Fixes #13610

crates/uv-python/fetch-download-metadata.py

@@ -64,6 +64,11 @@ VERSIONS_FILE = SELF_DIR / "download-metadata.json"
 # The date at which the default CPython musl builds became dynamically linked
 # instead of statically.
 CPYTHON_MUSL_STATIC_RELEASE_END = 20250311
+# The date at which the linux CPython builds started to have seemingly buggy runtimes
+CPYTHON_BAD_LINUX_RUNTIME_START = 20250517
+# This alpha was introduced in the bad linux runtime, and we don't want to show it
+# only on some platforms, so hide it everywhere.
+CPYTHON_HIDDEN_ALPHA = "3.14.0a7"
 
 
 def batched(iterable: Iterable, n: int) -> Generator[tuple, None, None]:
@@ -264,6 +269,14 @@ class CPythonFinder(Finder):
                         and download.triple.libc == "musl"
                     ):
                         continue
+                    if (
+                        download.release >= CPYTHON_BAD_LINUX_RUNTIME_START
+                        and download.triple.platform == "linux"
+                        and download.triple.arch.family != "aarch64"
+                    ):
+                        continue
+                    if str(download.version) == CPYTHON_HIDDEN_ALPHA:
+                        continue
                     logging.debug("Found %s (%s)", download.key(), download.filename)
                     downloads_by_version.setdefault(download.version, []).append(
                         download

crates/uv/tests/it/python_install.rs

@@ -3,8 +3,9 @@ use std::{env, path::Path, process::Command};
 use crate::common::{TestContext, uv_snapshot};
 use assert_fs::{
     assert::PathAssert,
-    prelude::{FileTouch, PathChild, PathCreateDir},
+    prelude::{FileTouch, FileWriteStr, PathChild, PathCreateDir},
 };
+use indoc::indoc;
 use predicates::prelude::predicate;
 use tracing::debug;
 use uv_fs::Simplified;
@@ -286,6 +287,41 @@ fn python_install_automatic() {
     }
 }
 
+/// Regression test for a bad cpython runtime
+/// <https://github.com/astral-sh/uv/issues/13610>
+#[test]
+fn regression_cpython() {
+    let context: TestContext = TestContext::new_with_versions(&[])
+        .with_filtered_python_keys()
+        .with_filtered_exe_suffix()
+        .with_filtered_python_sources()
+        .with_managed_python_dirs();
+
+    let init = context.temp_dir.child("mre.py");
+    init.write_str(indoc! { r#"
+        class Foo(str): ...
+
+        a = []
+        new_value = Foo("1")
+        a += new_value
+        "#
+    })
+    .unwrap();
+
+    // We should respect the Python request
+    uv_snapshot!(context.filters(), context.run()
+        .env_remove("VIRTUAL_ENV")
+        .arg("-p").arg("3.12")
+        .arg("mre.py"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+
+    "###);
+}
+
 #[test]
 fn python_install_preview() {
     let context: TestContext = TestContext::new_with_versions(&[])
@@ -1220,8 +1256,8 @@ fn python_install_314() {
     ----- stdout -----
 
     ----- stderr -----
-    Installed Python 3.14.0a7 in [TIME]
-     + cpython-3.14.0a7-[PLATFORM]
+    Installed Python 3.14.0a6 in [TIME]
+     + cpython-3.14.0a6-[PLATFORM]
     ");
 
     // Install a specific pre-release
@@ -1241,7 +1277,7 @@ fn python_install_314() {
     success: true
     exit_code: 0
     ----- stdout -----
-    [TEMP_DIR]/managed/cpython-3.14.0a7-[PLATFORM]/[INSTALL-BIN]/python
+    [TEMP_DIR]/managed/cpython-3.14.0a6-[PLATFORM]/[INSTALL-BIN]/python
 
     ----- stderr -----
     ");
@@ -1251,7 +1287,7 @@ fn python_install_314() {
     success: true
     exit_code: 0
     ----- stdout -----
-    [TEMP_DIR]/managed/cpython-3.14.0a7-[PLATFORM]/[INSTALL-BIN]/python
+    [TEMP_DIR]/managed/cpython-3.14.0a6-[PLATFORM]/[INSTALL-BIN]/python
 
     ----- stderr -----
     ");
@@ -1260,7 +1296,7 @@ fn python_install_314() {
     success: true
     exit_code: 0
     ----- stdout -----
-    [TEMP_DIR]/managed/cpython-3.14.0a7-[PLATFORM]/[INSTALL-BIN]/python
+    [TEMP_DIR]/managed/cpython-3.14.0a6-[PLATFORM]/[INSTALL-BIN]/python
 
     ----- stderr -----
     ");