Enhance reading from .python-version (#787)

* Enhance reading from .python-version

* Fix typos

* Fix lint

* Add built files

* Don't use EOL versions in `utils.test.ts`

* Fix Prettier

* Don't use unreleased versions in `utils.test.ts`

* Update versions in `utils.test.ts` again

src/setup-python.ts

@@ -11,7 +11,7 @@ import {
   logWarning,
   IS_MAC,
   getVersionInputFromFile,
-  getVersionInputFromPlainFile
+  getVersionsInputFromPlainFile
 } from './utils';
 
 function isPyPyVersion(versionSpec: string) {
@@ -35,7 +35,7 @@ async function cacheDependencies(cache: string, pythonVersion: string) {
 
 function resolveVersionInputFromDefaultFile(): string[] {
   const couples: [string, (versionFile: string) => string[]][] = [
-    ['.python-version', getVersionInputFromPlainFile]
+    ['.python-version', getVersionsInputFromPlainFile]
   ];
   for (const [versionFile, _fn] of couples) {
     logWarning(

src/utils.ts

@@ -228,7 +228,7 @@ function extractValue(obj: any, keys: string[]): string | undefined {
  * If none is present, returns an empty list.
  */
 export function getVersionInputFromTomlFile(versionFile: string): string[] {
-  core.debug(`Trying to resolve version form ${versionFile}`);
+  core.debug(`Trying to resolve version from ${versionFile}`);
 
   let pyprojectFile = fs.readFileSync(versionFile, 'utf8');
   // Normalize the line endings in the pyprojectFile
@@ -269,13 +269,28 @@ export function getVersionInputFromTomlFile(versionFile: string): string[] {
 }
 
 /**
- * Python version extracted from a plain text file.
+ * Python versions extracted from a plain text file.
+ * - Resolves multiple versions from multiple lines.
+ * - Handles pyenv-virtualenv pointers (e.g. `3.10/envs/virtualenv`).
+ * - Ignores empty lines and lines starting with `#`
+ * - Trims whitespace.
  */
-export function getVersionInputFromPlainFile(versionFile: string): string[] {
-  core.debug(`Trying to resolve version form ${versionFile}`);
-  const version = fs.readFileSync(versionFile, 'utf8').trim();
-  core.info(`Resolved ${versionFile} as ${version}`);
-  return [version];
+export function getVersionsInputFromPlainFile(versionFile: string): string[] {
+  core.debug(`Trying to resolve versions from ${versionFile}`);
+  const content = fs.readFileSync(versionFile, 'utf8').trim();
+  const lines = content.split(/\r\n|\r|\n/);
+  const versions = lines
+    .map(line => {
+      if (line.startsWith('#') || line.trim() === '') {
+        return undefined;
+      }
+      let version: string = line.trim();
+      version = version.split('/')[0];
+      return version;
+    })
+    .filter(version => version !== undefined) as string[];
+  core.info(`Resolved ${versionFile} as ${versions.join(', ')}`);
+  return versions;
 }
 
 /**
@@ -319,7 +334,7 @@ export function getVersionInputFromFile(versionFile: string): string[] {
   } else if (versionFile.match('.tool-versions')) {
     return getVersionInputFromToolVersions(versionFile);
   } else {
-    return getVersionInputFromPlainFile(versionFile);
+    return getVersionsInputFromPlainFile(versionFile);
   }
 }