Read python version from pyproject.toml (fix #542) (#669)

src/setup-python.ts

@@ -5,7 +5,13 @@ import * as path from 'path';
 import * as os from 'os';
 import fs from 'fs';
 import {getCacheDistributor} from './cache-distributions/cache-factory';
-import {isCacheFeatureAvailable, logWarning, IS_MAC} from './utils';
+import {
+  isCacheFeatureAvailable,
+  logWarning,
+  IS_MAC,
+  getVersionInputFromFile,
+  getVersionInputFromPlainFile
+} from './utils';
 
 function isPyPyVersion(versionSpec: string) {
   return versionSpec.startsWith('pypy');
@@ -22,43 +28,46 @@ async function cacheDependencies(cache: string, pythonVersion: string) {
   await cacheDistributor.restoreCache();
 }
 
-function resolveVersionInput() {
-  const versions = core.getMultilineInput('python-version');
-  let versionFile = core.getInput('python-version-file');
-
-  if (versions.length && versionFile) {
-    core.warning(
-      'Both python-version and python-version-file inputs are specified, only python-version will be used.'
+function resolveVersionInputFromDefaultFile(): string[] {
+  const couples: [string, (versionFile: string) => string[]][] = [
+    ['.python-version', getVersionInputFromPlainFile]
+  ];
+  for (const [versionFile, _fn] of couples) {
+    logWarning(
+      `Neither 'python-version' nor 'python-version-file' inputs were supplied. Attempting to find '${versionFile}' file.`
     );
+    if (fs.existsSync(versionFile)) {
+      return _fn(versionFile);
+    } else {
+      logWarning(`${versionFile} doesn't exist.`);
+    }
   }
+  return [];
+}
+
+function resolveVersionInput() {
+  let versions = core.getMultilineInput('python-version');
+  const versionFile = core.getInput('python-version-file');
 
   if (versions.length) {
-    return versions;
-  }
-
-  if (versionFile) {
-    if (!fs.existsSync(versionFile)) {
-      throw new Error(
-        `The specified python version file at: ${versionFile} doesn't exist.`
+    if (versionFile) {
+      core.warning(
+        'Both python-version and python-version-file inputs are specified, only python-version will be used.'
       );
     }
-    const version = fs.readFileSync(versionFile, 'utf8');
-    core.info(`Resolved ${versionFile} as ${version}`);
-    return [version];
+  } else {
+    if (versionFile) {
+      if (!fs.existsSync(versionFile)) {
+        throw new Error(
+          `The specified python version file at: ${versionFile} doesn't exist.`
+        );
+      }
+      versions = getVersionInputFromFile(versionFile);
+    } else {
+      versions = resolveVersionInputFromDefaultFile();
+    }
   }
 
-  logWarning(
-    "Neither 'python-version' nor 'python-version-file' inputs were supplied. Attempting to find '.python-version' file."
-  );
-  versionFile = '.python-version';
-  if (fs.existsSync(versionFile)) {
-    const version = fs.readFileSync(versionFile, 'utf8');
-    core.info(`Resolved ${versionFile} as ${version}`);
-    return [version];
-  }
-
-  logWarning(`${versionFile} doesn't exist.`);
-
   return versions;
 }
 

src/utils.ts

@@ -4,6 +4,7 @@ import * as core from '@actions/core';
 import fs from 'fs';
 import * as path from 'path';
 import * as semver from 'semver';
+import * as toml from '@iarna/toml';
 import * as exec from '@actions/exec';
 
 export const IS_WINDOWS = process.platform === 'win32';
@@ -181,3 +182,73 @@ export async function getOSInfo() {
     return osInfo;
   }
 }
+
+/**
+ * Extract a value from an object by following the keys path provided.
+ * If the value is present, it is returned. Otherwise undefined is returned.
+ */
+function extractValue(obj: any, keys: string[]): string | undefined {
+  if (keys.length > 0) {
+    const value = obj[keys[0]];
+    if (keys.length > 1 && value !== undefined) {
+      return extractValue(value, keys.slice(1));
+    } else {
+      return value;
+    }
+  } else {
+    return;
+  }
+}
+
+/**
+ * Python version extracted from the TOML file.
+ * If the `project` key is present at the root level, the version is assumed to
+ * be specified according to PEP 621 in `project.requires-python`.
+ * Otherwise, if the `tool` key is present at the root level, the version is
+ * assumed to be specified using poetry under `tool.poetry.dependencies.python`.
+ * If none is present, returns an empty list.
+ */
+export function getVersionInputFromTomlFile(versionFile: string): string[] {
+  core.debug(`Trying to resolve version form ${versionFile}`);
+
+  const pyprojectFile = fs.readFileSync(versionFile, 'utf8');
+  const pyprojectConfig = toml.parse(pyprojectFile);
+  let keys = [];
+
+  if ('project' in pyprojectConfig) {
+    // standard project metadata (PEP 621)
+    keys = ['project', 'requires-python'];
+  } else {
+    // python poetry
+    keys = ['tool', 'poetry', 'dependencies', 'python'];
+  }
+  const versions = [];
+  const version = extractValue(pyprojectConfig, keys);
+  if (version !== undefined) {
+    versions.push(version);
+  }
+
+  core.info(`Extracted ${versions} from ${versionFile}`);
+  return Array.from(versions, version => version.split(',').join(' '));
+}
+
+/**
+ * Python version extracted from a plain text file.
+ */
+export function getVersionInputFromPlainFile(versionFile: string): string[] {
+  core.debug(`Trying to resolve version form ${versionFile}`);
+  const version = fs.readFileSync(versionFile, 'utf8');
+  core.info(`Resolved ${versionFile} as ${version}`);
+  return [version];
+}
+
+/**
+ * Python version extracted from a plain or TOML file.
+ */
+export function getVersionInputFromFile(versionFile: string): string[] {
+  if (versionFile.endsWith('.toml')) {
+    return getVersionInputFromTomlFile(versionFile);
+  } else {
+    return getVersionInputFromPlainFile(versionFile);
+  }
+}