Address review feedback: use PYENV_ROOT, revert to 2-levels-up, fix tests

- Use PYENV_ROOT env var as primary source for pyenv root directory
- Revert 3-levels-up Windows logic to 2-levels-up (pyenv-win versions
  are at ~/.pyenv/pyenv-win/versions/, not ~/.pyenv/versions/)
- Add test for PYENV_ROOT preference
- Fix POSIX test to use absolute paths with path.sep
- Fix Windows test expectation to reflect correct 2-levels-up behavior

Co-authored-by: karthiknadig <3840081+karthiknadig@users.noreply.github.com>

Author: Copilot

src/managers/pyenv/pyenvUtils.ts

@@ -25,12 +25,15 @@ import { shortVersion, sortEnvironments } from '../common/utils';
 
 /**
  * Returns the pyenv root directory from the pyenv executable path.
- * On Windows, pyenv-win is at `~/.pyenv/pyenv-win/bin/pyenv.bat` (3 levels up).
- * On POSIX, pyenv is at `~/.pyenv/bin/pyenv` (2 levels up).
+ * Prefers `PYENV_ROOT` env var when set, otherwise goes up 2 levels from the binary.
+ * On POSIX, pyenv binary is at `<root>/bin/pyenv` (e.g. `~/.pyenv/bin/pyenv`).
+ * On Windows, pyenv-win binary is at `<root>/bin/pyenv.bat` (e.g. `~/.pyenv/pyenv-win/bin/pyenv.bat`,
+ * where `<root>` is `~/.pyenv/pyenv-win`).
  */
 export function getPyenvDir(pyenv: string): string {
-    if (isWindows()) {
-        return path.dirname(path.dirname(path.dirname(pyenv)));
+    const pyenvRoot = process.env.PYENV_ROOT;
+    if (pyenvRoot) {
+        return pyenvRoot;
     }
     return path.dirname(path.dirname(pyenv));
 }

src/test/managers/pyenv/pyenvUtils.unit.test.ts

@@ -1,33 +1,44 @@
 import assert from 'node:assert';
 import * as path from 'path';
 import * as sinon from 'sinon';
-import * as platformUtils from '../../../common/utils/platformUtils';
 import { getPyenvDir } from '../../../managers/pyenv/pyenvUtils';
 
 suite('pyenvUtils - getPyenvDir', () => {
-    let isWindowsStub: sinon.SinonStub;
+    let originalPyenvRoot: string | undefined;
 
     setup(() => {
-        isWindowsStub = sinon.stub(platformUtils, 'isWindows');
+        originalPyenvRoot = process.env.PYENV_ROOT;
+        delete process.env.PYENV_ROOT;
     });
 
     teardown(() => {
         sinon.restore();
+        if (originalPyenvRoot !== undefined) {
+            process.env.PYENV_ROOT = originalPyenvRoot;
+        } else {
+            delete process.env.PYENV_ROOT;
+        }
     });
 
-    test('should go up 2 levels on POSIX (bin/pyenv -> pyenv root)', () => {
-        isWindowsStub.returns(false);
+    test('should use PYENV_ROOT when set', () => {
+        const pyenvRoot = path.join(path.sep, 'custom', 'pyenv', 'root');
+        process.env.PYENV_ROOT = pyenvRoot;
+        const pyenvBin = path.join(path.sep, 'other', 'bin', 'pyenv');
+        const result = getPyenvDir(pyenvBin);
+        assert.strictEqual(result, pyenvRoot);
+    });
+
+    test('should go up 2 levels on POSIX when PYENV_ROOT is not set (bin/pyenv -> pyenv root)', () => {
         // e.g. /home/user/.pyenv/bin/pyenv
-        const pyenvBin = path.join('home', 'user', '.pyenv', 'bin', 'pyenv');
+        const pyenvBin = path.join(path.sep, 'home', 'user', '.pyenv', 'bin', 'pyenv');
         const result = getPyenvDir(pyenvBin);
-        assert.strictEqual(result, path.join('home', 'user', '.pyenv'));
+        assert.strictEqual(result, path.join(path.sep, 'home', 'user', '.pyenv'));
     });
 
-    test('should go up 3 levels on Windows (pyenv-win/bin/pyenv.bat -> pyenv root)', () => {
-        isWindowsStub.returns(true);
-        // e.g. C:\Users\user\.pyenv\pyenv-win\bin\pyenv.bat
+    test('should go up 2 levels on Windows when PYENV_ROOT is not set (pyenv-win/bin/pyenv.bat -> pyenv-win)', () => {
+        // e.g. C:\Users\user\.pyenv\pyenv-win\bin\pyenv.bat -> C:\Users\user\.pyenv\pyenv-win
         const pyenvBin = path.join('C:', 'Users', 'user', '.pyenv', 'pyenv-win', 'bin', 'pyenv.bat');
         const result = getPyenvDir(pyenvBin);
-        assert.strictEqual(result, path.join('C:', 'Users', 'user', '.pyenv'));
+        assert.strictEqual(result, path.join('C:', 'Users', 'user', '.pyenv', 'pyenv-win'));
     });
 });