Don't load a library twice

+++ libraries.module	11 Jan 2011 19:05:32 -0000
@@ -359,6 +359,11 @@ function libraries_detect_library(&$libr
+  $loaded_libraries = &drupal_static(__FUNCTION__);
+  if (isset($loaded_libraries[$name])) {
+    return FALSE;

Let's squeeze a newline between the static and early return, and also return the statically cached value.

+++ libraries.module	11 Jan 2011 19:05:32 -0000
@@ -377,7 +382,9 @@ function libraries_load($name, $variant 
+  $count = libraries_load_files($library, $variant);
+  $loaded_libraries[$name] = TRUE;
+  return $count;

Let's assign the return value to $loaded_libraries[$name] instead of $count, and also simply return $loaded_libraries[$name] (optionally casted to bool)

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Since library A was already loaded, libraries_load('library_a') will return 0 which will be cast to FALSE, even though it would be fine to load library B.

This is exactly what I meant at the end of #1, we need to store and return the first/last return value (optionally casted to Boolean, or not).

+++ libraries.module	12 Jan 2011 10:35:03 -0000
@@ -359,25 +359,31 @@ function libraries_detect_library(&$libr
+  $loaded_libraries = &drupal_static(__FUNCTION__);

Needs to default to an array, otherwise $loaded_libraries might now always be an array.

+++ libraries.module	12 Jan 2011 10:35:03 -0000
@@ -359,25 +359,31 @@ function libraries_detect_library(&$libr
+    if (!$library['installed']) {
       return FALSE;
     }
...
+      if (!$library['variants'][$variant]['installed']) {
+        return FALSE;
+      }

Let's not early return here - instead, assign the already figured out value (FALSE) to the static cache and return that instead at the end of the function.

+++ libraries.module	12 Jan 2011 10:35:03 -0000
@@ -359,25 +359,31 @@ function libraries_detect_library(&$libr
+    $loaded_libraries[$name] = libraries_load_files($library, $variant);

This should be wrapped in a check for FALSE then.

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+++ libraries.module	15 Jan 2011 14:29:01 -0000
@@ -346,25 +346,37 @@ function libraries_detect_library(&$libr
+  $loaded_libraries = &drupal_static(__FUNCTION__);
...
+  if (empty($loaded_libraries)) {
+    $loaded_libraries = array();
   }

The second argument to drupal_static() specifies the default value; just move the array() in there.

+++ libraries.module	15 Jan 2011 14:29:01 -0000
@@ -346,25 +346,37 @@ function libraries_detect_library(&$libr
+    if (!$library['installed']) {
+      $loaded_libraries[$name] = FALSE;
+    }
...
+    if (!empty($variant) && !empty($library['variants'][$variant])) {
...
+      if (!$library['variants'][$variant]['installed']) {
+        $loaded_libraries[$name] = FALSE;
+      }
+      $library = array_merge($library, $library['variants'][$variant]);
+    }
+
+    if ($loaded_libraries[$name] != FALSE) {
+      $loaded_libraries[$name] = libraries_load_files($library, $variant);
     }

1) Let's initialize $loaded_libraries[$name] with FALSE early, and afterwards, negate the first if condition.

2) Let's turn the second if into an elseif, and drop the last if condition.

3) All of the !empty() in the second condition should bet isset().

4) I think the second condition should only check whether a variant name was passed, and regardless of whether it exists or not, we process it. In turn, the third condition should be sufficient when checking for !empty(variant][installed).

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Helping you out a bit here ;)

I didn't know "+=" works multi-dimensionally.

It doesn't ;) The operator adds each key of the right-hand array to the left-hand array, if the array key does not exist yet. In case it doesn't exist yet, the entire corresponding value of the right-hand array is taken over. Note that a left-hand array key with value NULL is also considered to exist; i.e., the operator basically uses array_key_exists(), not isset().

In this case, we merely need to ensure that there is a $variant key. That is, because if there is already a $variant key, then 'installed' is guaranteed to exist on it, too. Only if the $variant key does not exist, we need to ensure that it exists, so the subsequent array_merge() doesn't fail.

Clarified the rest. :)

Thanks for reporting, reviewing, and testing! Committed to HEAD.

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