Add resolution-strategy input to support oldest compatible version selection (#631)

Adds a new `resolution-strategy` input that allows users to choose
between installing the highest (default) or lowest compatible version
when resolving version ranges.

Author: Copilot

.github/workflows/test.yml

@@ -111,15 +111,25 @@ jobs:
             expected-version: "0.3.5"
           - version-input: ">=0.4.25,<0.5"
             expected-version: "0.4.30"
+          - version-input: ">=0.4.25,<0.5"
+            expected-version: "0.4.25"
+            resolution-strategy: "lowest"
+          - version-input: ">=0.1,<0.2"
+            expected-version: "0.1.45"
+            resolution-strategy: "highest"
+          - version-input: ">=0.1.0,<0.2"
+            expected-version: "0.1.0"
+            resolution-strategy: "lowest"
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
           persist-credentials: false
-      - name: Install version ${{ matrix.input.version-input }}
+      - name: Install version ${{ matrix.input.version-input }} with strategy ${{ matrix.input.resolution-strategy || 'highest' }}
         id: setup-uv
         uses: ./
         with:
           version: ${{ matrix.input.version-input }}
+          resolution-strategy: ${{ matrix.input.resolution-strategy || 'highest' }}
       - name: Correct version gets installed
         run: |
           if [ "$(uv --version)" != "uv ${{ matrix.input.expected-version }}" ]; then

README.md

@@ -15,6 +15,7 @@ Set up your GitHub Actions workflow with a specific version of [uv](https://docs
   - [Install the latest version](#install-the-latest-version)
   - [Install a specific version](#install-a-specific-version)
   - [Install a version by supplying a semver range or pep440 specifier](#install-a-version-by-supplying-a-semver-range-or-pep440-specifier)
+  - [Resolution strategy](#resolution-strategy)
   - [Install a version defined in a requirements or config file](#install-a-version-defined-in-a-requirements-or-config-file)
   - [Python version](#python-version)
   - [Activate environment](#activate-environment)
@@ -97,6 +98,25 @@ to install the latest version that satisfies the range.
     version: ">=0.4.25,<0.5"
 ```
 
+### Resolution strategy
+
+By default, when resolving version ranges, setup-uv will install the highest compatible version.
+You can change this behavior using the `resolution-strategy` input:
+
+```yaml
+- name: Install the lowest compatible version of uv
+  uses: astral-sh/setup-uv@v6
+  with:
+    version: ">=0.4.0"
+    resolution-strategy: "lowest"
+```
+
+The supported resolution strategies are:
+- `highest` (default): Install the latest version that satisfies the constraints
+- `lowest`: Install the oldest version that satisfies the constraints
+
+This can be useful for testing compatibility with older versions of uv, similar to uv's own `--resolution-strategy` option.
+
 ### Install a version defined in a requirements or config file
 
 You can use the `version-file` input to specify a file that contains the version of uv to install.

action.yml

@@ -77,6 +77,9 @@ inputs:
   add-problem-matchers:
     description: "Add problem matchers."
     default: "true"
+  resolution-strategy:
+    description: "Resolution strategy to use when resolving version ranges. 'highest' uses the latest compatible version, 'lowest' uses the oldest compatible version."
+    default: "highest"
 outputs:
   uv-version:
     description: "The installed uv version. Useful when using latest."

dist/save-cache/index.js

@@ -4,6 +4,7 @@ import * as core from "@actions/core";
 import * as tc from "@actions/tool-cache";
 import type { Endpoints } from "@octokit/types";
 import * as pep440 from "@renovatebot/pep440";
+import * as semver from "semver";
 import { OWNER, REPO, TOOL_CACHE_NAME } from "../utils/constants";
 import { Octokit } from "../utils/octokit";
 import type { Architecture, Platform } from "../utils/platforms";
@@ -134,6 +135,7 @@ export async function resolveVersion(
   versionInput: string,
   manifestFile: string | undefined,
   githubToken: string,
+  resolutionStrategy: "highest" | "lowest" = "highest",
 ): Promise<string> {
   core.debug(`Resolving version: ${versionInput}`);
   let version: string;
@@ -164,7 +166,10 @@ export async function resolveVersion(
   }
   const availableVersions = await getAvailableVersions(githubToken);
   core.debug(`Available versions: ${availableVersions}`);
-  const resolvedVersion = maxSatisfying(availableVersions, version);
+  const resolvedVersion =
+    resolutionStrategy === "lowest"
+      ? minSatisfying(availableVersions, version)
+      : maxSatisfying(availableVersions, version);
   if (resolvedVersion === undefined) {
     throw new Error(`No version found for ${version}`);
   }
@@ -264,3 +269,24 @@ function maxSatisfying(
   }
   return undefined;
 }
+
+function minSatisfying(
+  versions: string[],
+  version: string,
+): string | undefined {
+  // For semver, we need to use a different approach since tc.evaluateVersions only returns max
+  // Let's use semver directly for min satisfying
+  const minSemver = semver.minSatisfying(versions, version);
+  if (minSemver !== null) {
+    core.debug(`Found a version that satisfies the semver range: ${minSemver}`);
+    return minSemver;
+  }
+  const minPep440 = pep440.minSatisfying(versions, version);
+  if (minPep440 !== null) {
+    core.debug(
+      `Found a version that satisfies the pep440 specifier: ${minPep440}`,
+    );
+    return minPep440;
+  }
+  return undefined;
+}

dist/setup/index.js

@@ -21,6 +21,7 @@ import {
   manifestFile,
   pythonDir,
   pythonVersion,
+  resolutionStrategy,
   toolBinDir,
   toolDir,
   versionFile as versionFileInput,
@@ -120,7 +121,12 @@ async function determineVersion(
   manifestFile: string | undefined,
 ): Promise<string> {
   if (versionInput !== "") {
-    return await resolveVersion(versionInput, manifestFile, githubToken);
+    return await resolveVersion(
+      versionInput,
+      manifestFile,
+      githubToken,
+      resolutionStrategy,
+    );
   }
   if (versionFileInput !== "") {
     const versionFromFile = getUvVersionFromFile(versionFileInput);
@@ -129,7 +135,12 @@ async function determineVersion(
         `Could not determine uv version from file: ${versionFileInput}`,
       );
     }
-    return await resolveVersion(versionFromFile, manifestFile, githubToken);
+    return await resolveVersion(
+      versionFromFile,
+      manifestFile,
+      githubToken,
+      resolutionStrategy,
+    );
   }
   const versionFromUvToml = getUvVersionFromFile(
     `${workingDirectory}${path.sep}uv.toml`,
@@ -146,6 +157,7 @@ async function determineVersion(
     versionFromUvToml || versionFromPyproject || "latest",
     manifestFile,
     githubToken,
+    resolutionStrategy,
   );
 }
 

src/download/download-version.ts

@@ -27,6 +27,7 @@ export const githubToken = core.getInput("github-token");
 export const manifestFile = getManifestFile();
 export const addProblemMatchers =
   core.getInput("add-problem-matchers") === "true";
+export const resolutionStrategy = getResolutionStrategy();
 
 function getVersionFile(): string {
   const versionFileInput = core.getInput("version-file");
@@ -186,3 +187,16 @@ function getManifestFile(): string | undefined {
   }
   return undefined;
 }
+
+function getResolutionStrategy(): "highest" | "lowest" {
+  const resolutionStrategyInput = core.getInput("resolution-strategy");
+  if (resolutionStrategyInput === "lowest") {
+    return "lowest";
+  }
+  if (resolutionStrategyInput === "highest" || resolutionStrategyInput === "") {
+    return "highest";
+  }
+  throw new Error(
+    `Invalid resolution-strategy: ${resolutionStrategyInput}. Must be 'highest' or 'lowest'.`,
+  );
+}