astral-sh
@@ -44,7 +44,7 @@ Have a look under [Advanced Configuration](#advanced-configuration) for detailed
 - name: Install uv with all available options
   uses: astral-sh/setup-uv@c771a70e6277c0a99b617c7a806ffedaca235ff9 # v9.0.0
   with:
-    # The version of uv to install (default: searches for version in config files, then latest)
+    # The version of uv to install, e.g., "0.5.0", "latest", or "latest-known" (default: searches for version in config files, then latest)
     version: ""
 
     # Path to a file containing the version of uv to install, e.g., uv.toml, pyproject.toml, .tool-versions, requirements.txt or uv.lock (default: searches uv.toml then pyproject.toml)

@@ -0,0 +1,20 @@
+import { expect, it, jest } from "@jest/globals";
+
+jest.unstable_mockModule(
+  "../../../src/download/checksum/known-checksums",
+  () => ({
+    KNOWN_CHECKSUMS: {
+      "aarch64-apple-darwin-1.9.0": "checksum",
+      "x86_64-unknown-linux-gnu-1.8.0": "checksum",
+      "x86_64-unknown-linux-gnu-1.10.0": "checksum",
+    },
+  }),
+);
+
+const { getLatestKnownVersion } = await import(
+  "../../../src/download/checksum/known-version"
+);
+
+it("returns the highest version with a built-in checksum", () => {
+  expect(getLatestKnownVersion()).toBe("1.10.0");
+});
@@ -55,6 +55,12 @@ jest.unstable_mockModule("../../src/download/checksum/checksum", () => ({
   validateChecksum: mockValidateChecksum,
 }));
 
+const mockGetLatestKnownVersion = jest.fn(() => "0.9.25");
+
+jest.unstable_mockModule("../../src/download/checksum/known-version", () => ({
+  getLatestKnownVersion: mockGetLatestKnownVersion,
+}));
+
 const { downloadVersion, resolveVersion, rewriteToMirror } = await import(
   "../../src/download/download-version"
 );
@@ -72,6 +78,7 @@ describe("download-version", () => {
     mockGetFirstMatchingVersion.mockReset();
     mockGetArtifact.mockReset();
     mockValidateChecksum.mockReset();
+    mockGetLatestKnownVersion.mockClear();
 
     mockDownloadTool.mockResolvedValue("/tmp/downloaded");
     mockExtractTar.mockResolvedValue("/tmp/extracted");
@@ -90,6 +97,16 @@ describe("download-version", () => {
       expect(mockGetLatestVersion).toHaveBeenCalledWith(undefined);
     });
 
+    it("resolves latest-known without reading the manifest", async () => {
+      const version = await resolveVersion("latest-known", undefined);
+
+      expect(version).toBe("0.9.25");
+      expect(mockGetLatestKnownVersion).toHaveBeenCalledTimes(1);
+      expect(mockGetLatestVersion).not.toHaveBeenCalled();
+      expect(mockGetAllVersions).not.toHaveBeenCalled();
+      expect(mockGetFirstMatchingVersion).not.toHaveBeenCalled();
+    });
+
     it("stops at the first matching version in the default manifest", async () => {
       mockGetFirstMatchingVersion.mockImplementation(
         (predicate: (version: string) => boolean) =>

@@ -4,7 +4,7 @@ description:
 author: "astral-sh"
 inputs:
   version:
-    description: "The version of uv to install e.g., `0.5.0` Defaults to the version in pyproject.toml or 'latest'."
+    description: "The version of uv to install, e.g., `0.5.0`, `latest`, or `latest-known`. Defaults to the version in pyproject.toml or `latest`."
     default: ""
   version-file:
     description: "Path to a file containing the version of uv to install, e.g., uv.toml, pyproject.toml, .tool-versions, requirements.txt or uv.lock. Defaults to searching for uv.toml and if not found pyproject.toml."

@@ -11,6 +11,19 @@ This document covers advanced options for configuring which version of uv to ins
     version: "latest"
 ```
 
+## Install the latest version with a checksum verified by this action
+
+Use `latest-known` to install the newest uv version whose checksums were bundled with the version of setup-uv used by your workflow. Version resolution is performed locally without fetching the latest release, so updating setup-uv also updates the version selected by `latest-known`.
+
+When `manifest-file` is set, `latest-known` still selects a version from setup-uv's bundled checksum table, but the artifact and checksum come from the custom manifest.
+
+```yaml
+- name: Install the latest version of uv known to setup-uv
+  uses: astral-sh/setup-uv@c771a70e6277c0a99b617c7a806ffedaca235ff9 # v9.0.0
+  with:
+    version: "latest-known"
+```
+
 ## Install a specific version
 
 ```yaml

@@ -0,0 +1,23 @@
+import * as semver from "semver";
+import { KNOWN_CHECKSUMS } from "./known-checksums";
+
+const VERSION_IN_CHECKSUM_KEY_PATTERN =
+  /-(\d+\.\d+\.\d+(?:[-+][0-9A-Za-z.-]+)?)$/;
+
+export function getLatestKnownVersion(): string {
+  const versions = new Set<string>();
+
+  for (const key of Object.keys(KNOWN_CHECKSUMS)) {
+    const version = key.match(VERSION_IN_CHECKSUM_KEY_PATTERN)?.[1];
+    if (version !== undefined) {
+      versions.add(version);
+    }
+  }
+
+  const latestVersion = [...versions].sort(semver.rcompare)[0];
+  if (!latestVersion) {
+    throw new Error("Could not determine latest known version from checksums.");
+  }
+
+  return latestVersion;
+}
@@ -1,6 +1,6 @@
 import * as core from "@actions/core";
 import * as semver from "semver";
-import { KNOWN_CHECKSUMS } from "./download/checksum/known-checksums";
+import { getLatestKnownVersion } from "./download/checksum/known-version";
 import {
   type ChecksumEntry,
   updateChecksums,
@@ -12,9 +12,6 @@ import {
 } from "./download/manifest";
 import * as log from "./utils/logging";
 
-const VERSION_IN_CHECKSUM_KEY_PATTERN =
-  /-(\d+\.\d+\.\d+(?:[-+][0-9A-Za-z.-]+)?)$/;
-
 async function run(): Promise<void> {
   const checksumFilePath = process.argv.slice(2)[0];
   if (!checksumFilePath) {
@@ -24,7 +21,7 @@ async function run(): Promise<void> {
   }
 
   const latestVersion = await getLatestVersion();
-  const latestKnownVersion = getLatestKnownVersionFromChecksums();
+  const latestKnownVersion = getLatestKnownVersion();
 
   if (semver.lte(latestVersion, latestKnownVersion)) {
     log.info(
@@ -40,28 +37,6 @@ async function run(): Promise<void> {
   core.setOutput("latest-version", latestVersion);
 }
 
-function getLatestKnownVersionFromChecksums(): string {
-  const versions = new Set<string>();
-
-  for (const key of Object.keys(KNOWN_CHECKSUMS)) {
-    const version = extractVersionFromChecksumKey(key);
-    if (version !== undefined) {
-      versions.add(version);
-    }
-  }
-
-  const latestVersion = [...versions].sort(semver.rcompare)[0];
-  if (!latestVersion) {
-    throw new Error("Could not determine latest known version from checksums.");
-  }
-
-  return latestVersion;
-}
-
-function extractVersionFromChecksumKey(key: string): string | undefined {
-  return key.match(VERSION_IN_CHECKSUM_KEY_PATTERN)?.[1];
-}
-
 function extractChecksumsFromManifest(
   versions: ManifestVersion[],
 ): ChecksumEntry[] {

@@ -2,6 +2,7 @@ import * as core from "@actions/core";
 import * as tc from "@actions/tool-cache";
 import * as pep440 from "@renovatebot/pep440";
 import * as semver from "semver";
+import { getLatestKnownVersion } from "../download/checksum/known-version";
 import {
   getAllVersions,
   getFirstMatchingVersion,
@@ -143,6 +144,10 @@ export async function resolveVersion(
 ): Promise<string> {
   core.debug(`Resolving version: ${versionInput}`);
 
+  if (versionInput.trim() === "latest-known") {
+    return getLatestKnownVersion();
+  }
+
   const context: ConcreteVersionResolutionContext = {
     manifestUrl,
     parsedSpecifier: parseVersionSpecifier(versionInput),