async example do not work with hhvm v4

[AlphaWong]

Hi Community,

As I currently learn hacklang, It seems the sample code in this page https://docs.hhvm.com/hack/asynchronous-operations/some-basics is not runnable.

spec

hhvm --version
HipHop VM 4.18.0 (rel)
Compiler: 1565634828_N
Repo schema: 87cc9f3f8ece4c477c3bcf388b96a2a3031e653

issue

I find that if the run the sample code of

<?hh // strict

namespace Hack\UserDocumentation\AsyncOps\Basics\Examples\AsyncCurl;
use namespace HH\Lib\Vec;

async function curl_A(): Awaitable<string> {
  $x = await \HH\Asio\curl_exec("http://example.com/");
  return $x;
}

async function curl_B(): Awaitable<string> {
  $y = await \HH\Asio\curl_exec("http://example.net/");
  return $y;
}

async function async_curl(): Awaitable<void> {
  $start = \microtime(true);
  list($a, $b) = await Vec\from_async(vec[curl_A(), curl_B()]);
  $end = \microtime(true);
  echo "Total time taken: " . \strval($end - $start) . " seconds\n";
}

<<__EntryPoint>>
function main():void {
  \HH\Asio\join(async_curl());
}

It will always throw following error

Fatal error: Uncaught Error: Call to undefined function HH\Lib\Vec\from_async() in /Users/alphawong/works/src/github.com/alphawong/hello-hhvm/bin/async_func.hack:20
Stack trace:
#0 /Users/alphawong/works/src/github.com/alphawong/hello-hhvm/bin/async_func.hack(27): Hack\UserDocumentation\AsyncOps\Basics\Examples\AsyncCurl\async_curl()
#1 (): Hack\UserDocumentation\AsyncOps\Basics\Examples\AsyncCurl\main()
#2 {main}

When I Google it I find that I need to change require_once(__DIR__.'/../vendor/autoload.hack'); to require_once(__DIR__.'/../vendor/hh_autoload.hh); to make it runnable.

So I modify the currently sample code by split it to two file based on the hhvm version 4 like following added commit in order to let the tutorial working.

Please review my change.
#709

Best,
Alpha

[AlphaWong]

Also I have problem of the CI

Fatal error: Uncaught exception 'HH\InvariantException' with message 'none of /var/www/guides/hack/15-asynchronous-operations/04-some-basics-examples/async-curl.hack.example.hhvm.out, /var/www/guides/hack/15-asynchronous-operations/04-some-basics-examples/async-curl.hack.hhvm.expect, or /var/www/guides/hack/15-asynchronous-operations/04-some-basics-examples/async-curl.hack.no.auto.output exist.' in /var/www/src/markdown-extensions/ExampleIncludeBlock.php:101
Stack trace:
#0 /var/www/src/markdown-extensions/ExampleIncludeBlock.php(101): HH\invariant_violation()
#1 /var/www/src/markdown-extensions/ExampleIncludeBlock.php(68): HHVM\UserDocumentation\MarkdownExt\ExamplesIncludeBlock::getOutputBlock()
#2 /var/www/vendor/facebook/fbmarkdown/src/unparsed-blocks/ContainerBlock.php(68): HHVM\UserDocumentation\MarkdownExt\ExamplesIncludeBlock::consume()
#3 /var/www/vendor/facebook/fbmarkdown/src/unparsed-blocks/ContainerBlock.php(56): Facebook\Markdown\UnparsedBlocks\ContainerBlock::consumeSingleImpl()
#4 /var/www/vendor/facebook/fbmarkdown/src/unparsed-blocks/ContainerBlock.php(34): Facebook\Markdown\UnparsedBlocks\ContainerBlock::consumeSingle()
#5 /var/www/vendor/facebook/fbmarkdown/src/unparsed-blocks/Document.php(23): Facebook\Markdown\UnparsedBlocks\ContainerBlock::consumeChildren()
#6 /var/www/vendor/facebook/fbmarkdown/src/unparsed-blocks/parse.php(27): Facebook\Markdown\UnparsedBlocks\Document::consume()
#7 /var/www/vendor/facebook/fbmarkdown/src/parse.php(19): Facebook\Markdown\UnparsedBlocks\parse()
#8 /var/www/src/build/MarkdownRenderer.php(57): Facebook\Markdown\parse()
#9 /var/www/src/build/AbstractMarkdownRenderBuildStep.php(42): HHVM\UserDocumentation\MarkdownRenderer->renderMarkdownToHTML()
#10 /var/www/src/build/AbstractMarkdownRenderBuildStep.php(31): HHVM\UserDocumentation\AbstractMarkdownRenderBuildStep->renderFilesWithFBMarkdown()
#11 /var/www/src/build/GuidesHTMLBuildStep.php(30): HHVM\UserDocumentation\AbstractMarkdownRenderBuildStep->renderFiles()
#12 /var/www/bin/build.php(81): HHVM\UserDocumentation\GuidesHTMLBuildStep->buildAll()
#13 /var/www/bin/build.php(88): HHVM\UserDocumentation\build_site()
#14 {main}
The command '/bin/sh -c touch /docker_build && cd /var/www && .deploy/init.sh' returned a non-zero code: 255

How can I add the rename and add new file in the CI.