Add dotnet-version-file input to read the .NET SDK version from a file

README.md

@@ -150,6 +150,32 @@ steps:
 
 > **Important**: When using `rollForward` in `global.json`, the `sdk.version` field must be a fully-qualified SDK version (e.g., `8.0.100`, `10.0.100`). Wildcard versions (e.g., `10.0.*`) and runtime-style versions (e.g., `8.0.0`) are not supported. See the [.NET SDK version specification](https://learn.microsoft.com/en-us/dotnet/core/tools/global-json#version) for details.
 
+## Using the `dotnet-version-file` input
+`setup-dotnet` can read the .NET SDK version from a version file via the `dotnet-version-file` input. This is handy for sharing a single source of truth with tools such as [asdf](https://asdf-vm.com/) and [mise](https://mise.jdx.dev/). The input accepts:
+
+- a [`.tool-versions`](https://asdf-vm.com/manage/configuration.html#tool-versions) file — the version is read from its `dotnet` entry;
+- a `global.json` file — the version is read from its `sdk.version` field.
+
+If the file supplied to `dotnet-version-file` doesn't exist, the action fails. If the file exists but contains no .NET SDK version, a warning is logged and no version is installed from it.
+
+```yml
+steps:
+- uses: actions/checkout@v6
+- uses: actions/setup-dotnet@v5
+  with:
+    dotnet-version-file: .tool-versions
+- run: dotnet build <my project>
+```
+
+A `.tool-versions` file may pin several tools; only the `dotnet` entry is used:
+
+```
+nodejs 20.11.0
+dotnet 8.0.100
+```
+
+>**Note**: In case both `dotnet-version` and `dotnet-version-file` inputs are used, versions from both inputs will be installed.
+
 ## Caching NuGet Packages
 The action has a built-in functionality for caching and restoring dependencies. It uses [toolkit/cache](https://github.com/actions/toolkit/tree/main/packages/cache) under the hood for caching global packages data but requires less configuration settings. The `cache` input is optional, and caching is turned off by default.
 

__tests__/setup-dotnet.test.ts

@@ -66,6 +66,7 @@ describe('setup-dotnet tests', () => {
   const setOutputSpy = core.setOutput as jest.Mock;
 
   const existsSyncSpy = fs.existsSync as jest.Mock;
+  const readFileSyncSpy = fs.readFileSync as jest.Mock;
 
   const maxSatisfyingSpy = jest.spyOn(semver, 'maxSatisfying');
 
@@ -122,6 +123,80 @@ describe('setup-dotnet tests', () => {
       expect(infoSpy).toHaveBeenCalledWith(expectedInfoMessage);
     });
 
+    it('should fail the action if dotnet-version-file input is present, but the file does not exist in the file system', async () => {
+      inputs['dotnet-version'] = [];
+      inputs['global-json-file'] = '';
+      inputs['dotnet-version-file'] = '.tool-versions';
+
+      existsSyncSpy.mockReturnValue(false);
+
+      const expectedErrorMessage = `The specified dotnet-version-file '${inputs['dotnet-version-file']}' does not exist`;
+
+      await setup.run();
+      expect(setFailedSpy).toHaveBeenCalledWith(expectedErrorMessage);
+
+      inputs['dotnet-version-file'] = '';
+    });
+
+    it('should read the .NET SDK version from a .tool-versions file supplied via dotnet-version-file', async () => {
+      inputs['dotnet-version'] = [];
+      inputs['global-json-file'] = '';
+      inputs['dotnet-quality'] = '';
+      inputs['dotnet-version-file'] = '.tool-versions';
+
+      existsSyncSpy.mockReturnValue(true);
+      readFileSyncSpy.mockReturnValue('nodejs 20.0.0\ndotnet 8.0.100\n');
+      installDotnetSpy.mockImplementation(() => Promise.resolve('8.0.100'));
+      setOutputSpy.mockImplementation(() => {});
+
+      await setup.run();
+
+      expect(installDotnetSpy).toHaveBeenCalledTimes(1);
+      expect(setOutputSpy).toHaveBeenCalledWith('dotnet-version', '8.0.100');
+
+      inputs['dotnet-version-file'] = '';
+    });
+
+    it('should read the .NET SDK version from a global.json supplied via dotnet-version-file', async () => {
+      inputs['dotnet-version'] = [];
+      inputs['global-json-file'] = '';
+      inputs['dotnet-quality'] = '';
+      inputs['dotnet-version-file'] = 'csharp/global.json';
+
+      existsSyncSpy.mockReturnValue(true);
+      readFileSyncSpy.mockReturnValue('{"sdk":{"version":"8.0.100"}}');
+      installDotnetSpy.mockImplementation(() => Promise.resolve('8.0.100'));
+      setOutputSpy.mockImplementation(() => {});
+
+      await setup.run();
+
+      expect(installDotnetSpy).toHaveBeenCalledTimes(1);
+      expect(setOutputSpy).toHaveBeenCalledWith('dotnet-version', '8.0.100');
+
+      inputs['dotnet-version-file'] = '';
+    });
+
+    it('should warn and not install if dotnet-version-file has no dotnet entry', async () => {
+      inputs['dotnet-version'] = [];
+      inputs['global-json-file'] = '';
+      inputs['dotnet-version-file'] = '.tool-versions';
+
+      // The version file exists, but the fallback global.json in the repo root does not.
+      existsSyncSpy.mockImplementation(filePath =>
+        String(filePath).endsWith('.tool-versions')
+      );
+      readFileSyncSpy.mockReturnValue('nodejs 20.0.0\n# no dotnet here\n');
+
+      await setup.run();
+
+      expect(warningSpy).toHaveBeenCalledWith(
+        `No .NET SDK version was found in '${inputs['dotnet-version-file']}'. Make sure the file contains a 'dotnet' entry (.tool-versions) or an 'sdk.version' field (global.json).`
+      );
+      expect(installDotnetSpy).not.toHaveBeenCalled();
+
+      inputs['dotnet-version-file'] = '';
+    });
+
     it('should fail the action if quality is supplied but its value is not supported', async () => {
       inputs['global-json-file'] = '';
       inputs['dotnet-version'] = ['10.0'];

action.yml

@@ -17,6 +17,9 @@ inputs:
   global-json-file:
     description: 'Optional global.json location, if your global.json isn''t located in the root of the repo.'
     required: false
+  dotnet-version-file:
+    description: 'Optional path to a file with the .NET SDK version to install. Supports a .tool-versions file (asdf/mise format, reads the "dotnet" entry) or a global.json file.'
+    required: false
   source-url:
     description: 'Optional package source for which to set up authentication. Will consult any existing NuGet.config in the root of the repo and provide a temporary NuGet.config using the NUGET_AUTH_TOKEN environment variable as a ClearTextPassword'
     required: false

dist/setup/index.js

@@ -105747,6 +105747,20 @@ async function run() {
             }
             versions.push(getVersionFromGlobalJson(globalJsonPath));
         }
+        const versionFileInput = getInput('dotnet-version-file');
+        if (versionFileInput) {
+            const versionFilePath = external_path_default().resolve(process.cwd(), versionFileInput);
+            if (!external_fs_namespaceObject.existsSync(versionFilePath)) {
+                throw new Error(`The specified dotnet-version-file '${versionFileInput}' does not exist`);
+            }
+            const versionFromFile = getVersionFromFile(versionFilePath);
+            if (versionFromFile) {
+                versions.push(versionFromFile);
+            }
+            else {
+                warning(`No .NET SDK version was found in '${versionFileInput}'. Make sure the file contains a 'dotnet' entry (.tool-versions) or an 'sdk.version' field (global.json).`);
+            }
+        }
         if (!versions.length) {
             // Try to fall back to global.json
             core_debug('No version found, trying to find version from global.json');
@@ -105799,7 +105813,7 @@ async function run() {
         if (sourceUrl) {
             configAuthentication(sourceUrl, configFile);
         }
-        outputInstalledVersion(installedDotnetVersions, globalJsonFileInput);
+        outputInstalledVersion(installedDotnetVersions, globalJsonFileInput || versionFileInput);
         if (getBooleanInput('cache') && isCacheFeatureAvailable()) {
             const cacheDependencyPath = getInput('cache-dependency-path');
             await cache_restore_restoreCache(cacheDependencyPath);
@@ -105862,7 +105876,29 @@ function getVersionFromGlobalJson(globalJsonPath) {
     }
     return version;
 }
-function outputInstalledVersion(installedVersions, globalJsonFileInput) {
+function getVersionFromToolVersions(toolVersionsPath) {
+    const content = external_fs_namespaceObject.readFileSync(toolVersionsPath, { encoding: 'utf8' });
+    for (const line of content.split(/\r?\n/)) {
+        // A .tool-versions entry is `<tool> <version>`; lines starting with `#` are comments.
+        const trimmed = line.trim();
+        if (!trimmed || trimmed.startsWith('#'))
+            continue;
+        const [tool, version] = trimmed.split(/\s+/);
+        if (tool === 'dotnet' && version) {
+            return version;
+        }
+    }
+    return '';
+}
+function getVersionFromFile(versionFilePath) {
+    // Dispatch by file: a global.json is parsed as JSON, anything else
+    // (e.g. .tool-versions) is parsed in the asdf/mise `<tool> <version>` format.
+    if (external_path_default().basename(versionFilePath).toLowerCase().endsWith('.json')) {
+        return getVersionFromGlobalJson(versionFilePath);
+    }
+    return getVersionFromToolVersions(versionFilePath);
+}
+function outputInstalledVersion(installedVersions, versionFileInput) {
     if (!installedVersions.length) {
         info(`The '${Outputs.DotnetVersion}' output will not be set.`);
         return;
@@ -105871,8 +105907,8 @@ function outputInstalledVersion(installedVersions, globalJsonFileInput) {
         warning(`Failed to output the installed version of .NET. The '${Outputs.DotnetVersion}' output will not be set.`);
         return;
     }
-    if (globalJsonFileInput) {
-        const versionToOutput = installedVersions.at(-1); // .NET SDK version parsed from the global.json file is installed last
+    if (versionFileInput) {
+        const versionToOutput = installedVersions.at(-1); // .NET SDK version parsed from the version file is installed last
         setOutput(Outputs.DotnetVersion, versionToOutput);
         return;
     }

src/setup-dotnet.ts

@@ -90,6 +90,24 @@ export async function run() {
       versions.push(getVersionFromGlobalJson(globalJsonPath));
     }
 
+    const versionFileInput = core.getInput('dotnet-version-file');
+    if (versionFileInput) {
+      const versionFilePath = path.resolve(process.cwd(), versionFileInput);
+      if (!fs.existsSync(versionFilePath)) {
+        throw new Error(
+          `The specified dotnet-version-file '${versionFileInput}' does not exist`
+        );
+      }
+      const versionFromFile = getVersionFromFile(versionFilePath);
+      if (versionFromFile) {
+        versions.push(versionFromFile);
+      } else {
+        core.warning(
+          `No .NET SDK version was found in '${versionFileInput}'. Make sure the file contains a 'dotnet' entry (.tool-versions) or an 'sdk.version' field (global.json).`
+        );
+      }
+    }
+
     if (!versions.length) {
       // Try to fall back to global.json
       core.debug('No version found, trying to find version from global.json');
@@ -167,7 +185,10 @@ export async function run() {
       auth.configAuthentication(sourceUrl, configFile);
     }
 
-    outputInstalledVersion(installedDotnetVersions, globalJsonFileInput);
+    outputInstalledVersion(
+      installedDotnetVersions,
+      globalJsonFileInput || versionFileInput
+    );
 
     if (core.getBooleanInput('cache') && isCacheFeatureAvailable()) {
       const cacheDependencyPath = core.getInput('cache-dependency-path');
@@ -249,9 +270,32 @@ function getVersionFromGlobalJson(globalJsonPath: string): string {
   return version;
 }
 
+function getVersionFromToolVersions(toolVersionsPath: string): string {
+  const content = fs.readFileSync(toolVersionsPath, {encoding: 'utf8'});
+  for (const line of content.split(/\r?\n/)) {
+    // A .tool-versions entry is `<tool> <version>`; lines starting with `#` are comments.
+    const trimmed = line.trim();
+    if (!trimmed || trimmed.startsWith('#')) continue;
+    const [tool, version] = trimmed.split(/\s+/);
+    if (tool === 'dotnet' && version) {
+      return version;
+    }
+  }
+  return '';
+}
+
+function getVersionFromFile(versionFilePath: string): string {
+  // Dispatch by file: a global.json is parsed as JSON, anything else
+  // (e.g. .tool-versions) is parsed in the asdf/mise `<tool> <version>` format.
+  if (path.basename(versionFilePath).toLowerCase().endsWith('.json')) {
+    return getVersionFromGlobalJson(versionFilePath);
+  }
+  return getVersionFromToolVersions(versionFilePath);
+}
+
 function outputInstalledVersion(
   installedVersions: (string | null)[],
-  globalJsonFileInput: string
+  versionFileInput: string
 ): void {
   if (!installedVersions.length) {
     core.info(`The '${Outputs.DotnetVersion}' output will not be set.`);
@@ -265,8 +309,8 @@ function outputInstalledVersion(
     return;
   }
 
-  if (globalJsonFileInput) {
-    const versionToOutput = installedVersions.at(-1); // .NET SDK version parsed from the global.json file is installed last
+  if (versionFileInput) {
+    const versionToOutput = installedVersions.at(-1); // .NET SDK version parsed from the version file is installed last
     core.setOutput(Outputs.DotnetVersion, versionToOutput);
     return;
   }