Update Celerity map parser for new docblock code

Summary:
After D16431, listing the same `@annotation` multiple times makes the docblock parser return a list.

We have some resources which list `@requires` or `@provides` several times, but don't handle the new parser properly. Make the code more flexible, since this is a reasonable way to specify the annotations.

See also D16432. This produces a failure in this form:

```
[2016-08-23 21:10:15] ERROR 2: trim() expects parameter 1 to be string, array given at [/core/data/drydock/workingcopy-74/repo/phabricator/src/applications/celerity/CelerityResourceMapGenerator.php:236]
2	arcanist(head=master, ref.master=89e8b4852384), phabricator(head=6c940fb71b0a8850c6a1b7f5fc642a8f8135a76a, ref.master=b521f2349e46), phutil(head=master, ref.master=237549280f08)
3	  #0 trim(array) called at [<phabricator>/src/applications/celerity/CelerityResourceMapGenerator.php:236]
4	  #1 CelerityResourceMapGenerator::getProvidesAndRequires(string, string) called at [<phabricator>/src/applications/celerity/CelerityResourceMapGenerator.php:193]
5	  #2 CelerityResourceMapGenerator::rebuildTextResources(CelerityPhabricatorResources, CelerityResourceTransformer) called at [<phabricator>/src/applications/celerity/CelerityResourceMapGenerator.php:54]
6	  #3 CelerityResourceMapGenerator::generate() called at [<phabricator>/src/__tests__/PhabricatorCelerityTestCase.php:16]
7	  phacility#4 PhabricatorCelerityTestCase::testCelerityMaps()
8	  phacility#5 call_user_func_array(array, array) called at [<arcanist>/src/unit/engine/phutil/PhutilTestCase.php:492]
9	  phacility#6 PhutilTestCase::run() called at [<arcanist>/src/unit/engine/PhutilUnitTestEngine.php:69]
10	  phacility#7 PhutilUnitTestEngine::run() called at [<arcanist>/src/unit/engine/ArcanistConfigurationDrivenUnitTestEngine.php:147]
11	  phacility#8 ArcanistConfigurationDrivenUnitTestEngine::run() called at [<arcanist>/src/workflow/ArcanistUnitWorkflow.php:167]
12	  #9 ArcanistUnitWorkflow::run() called at [<arcanist>/scripts/arcanist.php:394]
```

Test Plan: Ran `bin/celerity map`, no more warnings and no change to the actual map.

Reviewers: joshuaspence, chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D16433

Author: epriestley

src/applications/celerity/CelerityResourceMapGenerator.php

@@ -232,11 +232,8 @@ private function getProvidesAndRequires($name, $data) {
 
     list($description, $metadata) = $parser->parse($matches[0]);
 
-    $provides = preg_split('/\s+/', trim(idx($metadata, 'provides')));
-    $requires = preg_split('/\s+/', trim(idx($metadata, 'requires')));
-    $provides = array_filter($provides);
-    $requires = array_filter($requires);
-
+    $provides = $this->parseResourceSymbolList(idx($metadata, 'provides'));
+    $requires = $this->parseResourceSymbolList(idx($metadata, 'requires'));
     if (!$provides) {
       // Tests and documentation-only JS is permitted to @provide no targets.
       return array(null, null);
@@ -364,4 +361,37 @@ private function mergeNameMaps(array $maps) {
     return $result;
   }
 
+  private function parseResourceSymbolList($list) {
+    if (!$list) {
+      return array();
+    }
+
+    // This is valid:
+    //
+    //   @requires x y
+    //
+    // But so is this:
+    //
+    //   @requires x
+    //   @requires y
+    //
+    // Accept either form and produce a list of symbols.
+
+    $list = (array)$list;
+
+    // We can get `true` values if there was a bare `@requires` in the input.
+    foreach ($list as $key => $item) {
+      if ($item === true) {
+        unset($list[$key]);
+      }
+    }
+
+    $list = implode(' ', $list);
+    $list = trim($list);
+    $list = preg_split('/\s+/', $list);
+    $list = array_filter($list);
+
+    return $list;
+  }
+
 }