Use where on Windows to detect devcontainer cli

plugin/core/devcontainer.js

@@ -64,11 +64,13 @@ async function runCommand(cmd, args, options = {}) {
 /**
  * Check if the devcontainer CLI is installed
  * 
+ * @param {string} [platform] - Platform to check (defaults to process.platform)
  * @returns {Promise<boolean>}
  */
-export async function checkDevcontainerCli() {
+export async function checkDevcontainerCli(platform = process.platform) {
   try {
-    const result = await runCommand('which', ['devcontainer'])
+    const command = platform === 'win32' ? 'where' : 'which'
+    const result = await runCommand(command, ['devcontainer'])
     return result.success
   } catch {
     return false

test/unit/devcontainer.test.js

@@ -96,6 +96,19 @@ describe('checkDevcontainerCli', () => {
     const result = await checkDevcontainerCli()
     assert.strictEqual(typeof result, 'boolean')
   })
+
+  test('uses where command on win32', async () => {
+    // Note: 'where' command might not exist on non-Windows test environments (like Linux CI),
+    // which causes spawn to throw ENOENT instead of returning an exit code.
+    // Our checkDevcontainerCli function handles this gracefully with a try/catch, returning false.
+    const result = await checkDevcontainerCli('win32')
+    assert.strictEqual(typeof result, 'boolean')
+  })
+
+  test('uses which command on linux/darwin', async () => {
+    const result = await checkDevcontainerCli('linux')
+    assert.strictEqual(typeof result, 'boolean')
+  })
 })
 
 describe('list', () => {