PHP 5.6 syntax issues? Broken API integration

I’m trying to fix a broken integration with a job site’s API that I use on my site. I recently changed to the Sage theme and am using PHP 5.6.2. Before I migrated everything worked, and now it does not.

In my extras.php I’ve declared a few functions:

Function 1: slugify the job titles:

function slugify($text) {
  // replace non letter or digits by -
  $text = preg_replace('~[^\\pL\d]+~u', '-', $text);
  // trim
  $text = trim($text, '-');
  // transliterate
  $text = iconv('utf-8', 'us-ascii//TRANSLIT', $text);
  // lowercase
  $text = strtolower($text);
  // remove unwanted characters
  $text = preg_replace('~[^-\w]+~', '', $text);

  if (empty($text)) {
    return 'n-a';
  }
  return $text;
}
add_filter('slugify',  __NAMESPACE__ . '\\slugify');

Function 2: get the list of jobs:

function get_jobs() {
  $transient = 'lever_jobs';
  $json = get_transient($transient);

  if(false == $json) {
    $json = file_get_contents(LEVER_API_URL . '?mode=json');
    $json = json_decode($json);
    if(sizeof($json) > 0) {
      for ($i = 0; $i < count($json); $i++) {
        $json[$i]->slug = slugify($json[$i]->text);
      }
      set_transient($transient, $json, HOUR_IN_SECONDS);
    }
  }
  return $json;
}
add_filter('get_jobs',  __NAMESPACE__ . '\\get_jobs');

Function 3: get job form errors:

function get_job_form_errors($postdata, $files) {
  $output = array();

  if(strlen($postdata['fullname']) == 0) {
    $output['fullname'] = true;
  }
  if(!is_email($postdata['email'])) {
    $output['email'] = true;
  }
  if (empty($_FILES["resume"]['name'])) {
    $output['resume'] = true;
  }
  return $output;
}
add_filter('get_job_form_errors',  __NAMESPACE__ . '\\get_job_form_errors');

Function 4: submit the job to Lever:

function submit_to_lever($jobid, $postdata, $files) {
  $ch = curl_init(LEVER_API_URL . $jobid . '?key=' . LEVER_API_KEY);

  $f = $_FILES['resume']['tmp_name'];
  if(is_uploaded_file($f)) {
    $postdata['resume'] = "@$f;filename=".$_FILES['resume']['name'];
  }

  // curl doesnt support multi-dimensional arrays
  if(is_array($postdata['urls'])) {
    foreach ($postdata['urls'] as $key => $value) {
      $postdata["urls['$key']"] = $value;
    }
    unset($postdata['urls']);
  }

  $postdata['name'] = $postdata['fullname'];
  unset($postdata['fullname']);

  curl_setopt($ch, CURLOPT_POSTFIELDS, $postdata);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  curl_exec($ch);
  curl_close($ch);
}
add_filter('submit_to_lever',  __NAMESPACE__ . '\\submit_to_lever');

And then, in my template file, I call these functions at the top:

<?php
  $jobs = Roots\Sage\Extras\get_jobs();
  $is_post = False;
  $form_submitted = False;
  $errors = [];

  if($_SERVER['REQUEST_METHOD'] == 'POST') {
    $is_post = True;
    $postdata = $_POST;
    var_dump($postdata);
    $files = $_FILES;
    parse_str($_SERVER['QUERY_STRING']);

    $errors = Roots\Sage\Extras\get_job_form_errors($postdata, $files);

    if (sizeof($errors) == 0) {
      Roots\Sage\Extras\submit_to_lever($jobid, $postdata, $files);
      // var_dump($jobid);
      $form_submitted = True;
    }
  }
  }
?>

I’m able to get my job postings, and am able to echo what I need to in most parts of the template, except for this part:

<?php
  $cur_job = null;

  foreach($jobs as $one) {
    if(isset($postdata['jobid'])) {
      if($one->id == $postdata['jobid']) {
        $cur_job = $one;
        break;
      }
    }
  }
?>

For example, when I try outputting some of these values in an input, like this:

<input type="hidden" value="<?php echo isset($cur_job->id); ?>" name="jobid" />

I get index errors…

Since everything was working properly prior to the PHP update, I’m convinced this is a syntax issue. I’ve researched what needed to be updated to the best of my ability, but there’s still clearly something wrong. What am I missing?