Add version-file input to read the Helm version from a .tool-versions file (#281)

* feat: add version-file input to read helm version from .tool-versions

* feat: validate semver shape of helm version from .tool-versions

src/run.test.ts

@@ -19,7 +19,8 @@ vi.mock('fs', async (importOriginal) => {
       readdirSync: vi.fn(),
       statSync: vi.fn(),
       chmodSync: vi.fn(),
-      readFileSync: vi.fn()
+      readFileSync: vi.fn(),
+      existsSync: vi.fn()
    }
 })
 
@@ -161,6 +162,140 @@ describe('run.ts', () => {
       expect(run.getValidVersion('3.8.0')).toBe('v3.8.0')
    })
 
+   test('parseToolVersions() - return the helm version from .tool-versions content', () => {
+      const content = ['nodejs 20.11.0', 'helm 3.14.0', 'terraform 1.7.0'].join(
+         '\n'
+      )
+      expect(run.parseToolVersions(content)).toBe('3.14.0')
+   })
+
+   test('parseToolVersions() - ignore comments and blank lines', () => {
+      const content = ['# tools', '', '   helm 3.15.2   ', ''].join('\n')
+      expect(run.parseToolVersions(content)).toBe('3.15.2')
+   })
+
+   test('parseToolVersions() - return the first version when several are listed', () => {
+      expect(run.parseToolVersions('helm 3.14.0 3.13.0')).toBe('3.14.0')
+   })
+
+   test('parseToolVersions() - return empty string when helm is not declared', () => {
+      expect(run.parseToolVersions('nodejs 20.11.0')).toBe('')
+   })
+
+   test('getVersionFromToolVersionsFile() - read the helm version from a file', () => {
+      vi.mocked(fs.existsSync).mockReturnValue(true)
+      vi.mocked(fs.readFileSync).mockReturnValue('helm 3.14.0')
+
+      expect(run.getVersionFromToolVersionsFile('.tool-versions')).toBe(
+         '3.14.0'
+      )
+      expect(fs.readFileSync).toHaveBeenCalledWith('.tool-versions', 'utf8')
+   })
+
+   test('getVersionFromToolVersionsFile() - throw when the file does not exist', () => {
+      vi.mocked(fs.existsSync).mockReturnValue(false)
+
+      expect(() =>
+         run.getVersionFromToolVersionsFile('missing.tool-versions')
+      ).toThrow("The version-file 'missing.tool-versions' does not exist")
+   })
+
+   test('getVersionFromToolVersionsFile() - throw when no helm version is present', () => {
+      vi.mocked(fs.existsSync).mockReturnValue(true)
+      vi.mocked(fs.readFileSync).mockReturnValue('nodejs 20.11.0')
+
+      expect(() =>
+         run.getVersionFromToolVersionsFile('.tool-versions')
+      ).toThrow("No helm version found in '.tool-versions'")
+   })
+
+   test('getVersionFromToolVersionsFile() - throw when the helm version is not semver-shaped', () => {
+      vi.mocked(fs.existsSync).mockReturnValue(true)
+      vi.mocked(fs.readFileSync).mockReturnValue('helm latest')
+
+      expect(() =>
+         run.getVersionFromToolVersionsFile('.tool-versions')
+      ).toThrow(
+         "The helm version 'latest' in '.tool-versions' is not a valid semantic version"
+      )
+   })
+
+   test('isSemVerShaped() - accept semver-shaped versions with or without a v prefix', () => {
+      expect(run.isSemVerShaped('3.14.0')).toBe(true)
+      expect(run.isSemVerShaped('v3.14.0')).toBe(true)
+      expect(run.isSemVerShaped('3.14.0-rc.1')).toBe(true)
+   })
+
+   test('isSemVerShaped() - reject values that are not semver-shaped', () => {
+      expect(run.isSemVerShaped('latest')).toBe(false)
+      expect(run.isSemVerShaped('3.14')).toBe(false)
+      expect(run.isSemVerShaped('abc')).toBe(false)
+   })
+
+   // Stubs the download chain so run() resolves to a cached helm binary,
+   // letting these tests focus on version-vs-version-file resolution.
+   const stubDownloadChain = () => {
+      vi.mocked(os.platform).mockReturnValue('linux')
+      vi.mocked(os.arch).mockReturnValue('x64')
+      vi.mocked(toolCache.find).mockReturnValue('pathToCachedDir')
+      vi.mocked(fs.chmodSync).mockImplementation(() => {})
+      vi.mocked(fs.readdirSync).mockReturnValue([
+         'helm' as unknown as fs.Dirent<NonSharedBuffer>
+      ])
+      vi.mocked(fs.statSync).mockReturnValue({
+         isDirectory: () => false
+      } as fs.Stats)
+   }
+
+   const inputs = (version: string, versionFile: string) =>
+      vi.mocked(core.getInput).mockImplementation((name: string) => {
+         if (name === 'version') return version
+         if (name === 'version-file') return versionFile
+         if (name === 'downloadBaseURL') return downloadBaseURL
+         return ''
+      })
+
+   test('run() - resolve the version from version-file when version is not set', async () => {
+      stubDownloadChain()
+      inputs('', '.tool-versions')
+      vi.mocked(fs.existsSync).mockReturnValue(true)
+      vi.mocked(fs.readFileSync).mockReturnValue('helm 3.14.0')
+
+      await run.run()
+
+      expect(core.warning).not.toHaveBeenCalled()
+      expect(toolCache.find).toHaveBeenCalledWith('helm', 'v3.14.0')
+      expect(core.setOutput).toHaveBeenCalledWith(
+         'helm-path',
+         path.join('pathToCachedDir', 'helm')
+      )
+   })
+
+   test('run() - resolve the version from version-file when version is left at the latest default', async () => {
+      stubDownloadChain()
+      inputs('latest', '.tool-versions')
+      vi.mocked(fs.existsSync).mockReturnValue(true)
+      vi.mocked(fs.readFileSync).mockReturnValue('helm 3.14.0')
+
+      await run.run()
+
+      expect(core.warning).not.toHaveBeenCalled()
+      expect(toolCache.find).toHaveBeenCalledWith('helm', 'v3.14.0')
+   })
+
+   test('run() - warn and prefer version over version-file when both are set', async () => {
+      stubDownloadChain()
+      inputs('3.5.0', '.tool-versions')
+
+      await run.run()
+
+      expect(core.warning).toHaveBeenCalledWith(
+         `Both 'version' and 'version-file' inputs are specified, only 'version' will be used.`
+      )
+      expect(fs.readFileSync).not.toHaveBeenCalled()
+      expect(toolCache.find).toHaveBeenCalledWith('helm', 'v3.5.0')
+   })
+
    test('walkSync() - return path to the all files matching fileToFind in dir', () => {
       vi.mocked(fs.readdirSync).mockImplementation((file, _?) => {
          if (file == 'mainFolder')

src/run.ts

@@ -13,11 +13,27 @@ const helmToolName = 'helm'
 export const stableHelmVersion = 'v3.18.4'
 
 export async function run() {
-   let version = core.getInput('version', {required: true})
+   let version = core.getInput('version')
+   const versionFile = core.getInput('version-file')
+
+   if (versionFile) {
+      if (version && version !== 'latest') {
+         core.warning(
+            `Both 'version' and 'version-file' inputs are specified, only 'version' will be used.`
+         )
+      } else {
+         version = getVersionFromToolVersionsFile(versionFile)
+         core.info(`Resolved Helm version '${version}' from '${versionFile}'`)
+      }
+   }
+
+   if (!version) {
+      version = 'latest'
+   }
 
    if (version !== 'latest' && version[0] !== 'v') {
-      core.info('Getting latest Helm version')
       version = getValidVersion(version)
+      core.info(`Normalized Helm version to '${version}'`)
    }
    if (version.toLocaleLowerCase() === 'latest') {
       version = await getLatestHelmVersion()
@@ -46,6 +62,51 @@ export function getValidVersion(version: string): string {
    return 'v' + version
 }
 
+// Matches a semantic version (major.minor.patch) with an optional leading 'v'
+// and optional pre-release / build-metadata suffixes, e.g. '3.14.0', 'v3.14.0',
+// '3.14.0-rc.1'.
+const semVerShape = /^v?\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?(?:\+[0-9A-Za-z.-]+)?$/
+
+// Returns true when version looks like a semantic version
+export function isSemVerShaped(version: string): boolean {
+   return semVerShape.test(version)
+}
+
+// Reads a .tool-versions file and returns the helm version declared in it
+export function getVersionFromToolVersionsFile(filePath: string): string {
+   if (!fs.existsSync(filePath)) {
+      throw new Error(`The version-file '${filePath}' does not exist`)
+   }
+   const content = fs.readFileSync(filePath, 'utf8')
+   const version = parseToolVersions(content)
+   if (!version) {
+      throw new Error(`No helm version found in '${filePath}'`)
+   }
+   if (!isSemVerShaped(version)) {
+      throw new Error(
+         `The helm version '${version}' in '${filePath}' is not a valid semantic version`
+      )
+   }
+   return version
+}
+
+// Parses .tool-versions content (asdf/mise format) and returns the first
+// helm version, or an empty string when none is declared. Lines look like
+// `helm 3.14.0`; comments (#) and blank lines are ignored.
+export function parseToolVersions(content: string): string {
+   for (const line of content.split(/\r?\n/)) {
+      const trimmed = line.trim()
+      if (!trimmed || trimmed.startsWith('#')) {
+         continue
+      }
+      const [tool, version] = trimmed.split(/\s+/)
+      if (tool === helmToolName && version) {
+         return version
+      }
+   }
+   return ''
+}
+
 // Gets the latest helm version or returns a default stable if getting latest fails
 export async function getLatestHelmVersion(): Promise<string> {
    try {