#112 #113 removing unused by-ref assignments (not needed at all)

Before:

+-----------------------------+----------------------------------+-------+--------+------+-----+-------------+-------------+-------------+-------------+-------------+----------+--------+-------------+
| benchmark                   | subject                          | group | params | revs | its | mem         | best        | mean        | mode        | worst       | stdev    | rstdev | diff        |
+-----------------------------+----------------------------------+-------+--------+------+-----+-------------+-------------+-------------+-------------+-------------+----------+--------+-------------+
| FetchCachedServicesBench    | benchFetchFactory1               |       | []     | 1000 | 20  | 964,792b    | 2.764μs     | 2.875μs     | 2.847μs     | 2.977μs     | 0.071μs  | 2.45%  | +2.64%      |
| FetchCachedServicesBench    | benchFetchInvokable1             |       | []     | 1000 | 20  | 964,792b    | 2.702μs     | 2.801μs     | 2.781μs     | 2.939μs     | 0.060μs  | 2.13%  | 0.00%       |
| FetchCachedServicesBench    | benchFetchService1               |       | []     | 1000 | 20  | 964,792b    | 2.831μs     | 2.948μs     | 2.970μs     | 3.047μs     | 0.068μs  | 2.31%  | +5.25%      |
| FetchCachedServicesBench    | benchFetchAlias1                 |       | []     | 1000 | 20  | 964,792b    | 2.686μs     | 2.812μs     | 2.838μs     | 2.908μs     | 0.065μs  | 2.32%  | +0.40%      |
| FetchCachedServicesBench    | benchFetchRecursiveAlias1        |       | []     | 1000 | 20  | 964,800b    | 2.812μs     | 2.911μs     | 2.930μs     | 3.021μs     | 0.067μs  | 2.32%  | +3.95%      |
| FetchCachedServicesBench    | benchFetchRecursiveAlias2        |       | []     | 1000 | 20  | 964,800b    | 2.747μs     | 2.862μs     | 2.935μs     | 2.961μs     | 0.074μs  | 2.59%  | +2.18%      |
| FetchCachedServicesBench    | benchFetchAbstractFactoryService |       | []     | 1000 | 20  | 964,808b    | 13.010μs    | 13.501μs    | 13.659μs    | 14.150μs    | 0.299μs  | 2.21%  | +382.09%    |
| FetchNewServiceManagerBench | benchFetchServiceManagerCreation |       | []     | 100  | 20  | 24,030,120b | 1,925.660μs | 1,962.191μs | 1,936.676μs | 2,009.680μs | 28.444μs | 1.45%  | +69,965.74% |
| FetchNewServicesBench       | benchFetchFactory1               |       | []     | 1000 | 10  | 967,480b    | 13.060μs    | 13.409μs    | 13.214μs    | 14.046μs    | 0.303μs  | 2.26%  | +378.82%    |
| FetchNewServicesBench       | benchBuildFactory1               |       | []     | 1000 | 10  | 967,480b    | 11.992μs    | 12.426μs    | 12.285μs    | 12.991μs    | 0.310μs  | 2.49%  | +343.69%    |
| FetchNewServicesBench       | benchFetchInvokable1             |       | []     | 1000 | 10  | 967,480b    | 13.611μs    | 14.086μs    | 14.041μs    | 14.667μs    | 0.291μs  | 2.07%  | +402.98%    |
| FetchNewServicesBench       | benchBuildInvokable1             |       | []     | 1000 | 10  | 967,480b    | 12.400μs    | 12.837μs    | 13.069μs    | 13.199μs    | 0.296μs  | 2.31%  | +358.40%    |
| FetchNewServicesBench       | benchFetchService1               |       | []     | 1000 | 10  | 967,480b    | 2.723μs     | 2.814μs     | 2.762μs     | 2.939μs     | 0.068μs  | 2.42%  | +0.46%      |
| FetchNewServicesBench       | benchFetchFactoryAlias1          |       | []     | 1000 | 10  | 967,480b    | 12.683μs    | 13.027μs    | 12.956μs    | 13.508μs    | 0.251μs  | 1.93%  | +365.15%    |
| FetchNewServicesBench       | benchBuildFactoryAlias1          |       | []     | 1000 | 10  | 967,480b    | 12.385μs    | 12.893μs    | 12.766μs    | 13.410μs    | 0.322μs  | 2.50%  | +360.39%    |
| FetchNewServicesBench       | benchFetchRecursiveFactoryAlias1 |       | []     | 1000 | 10  | 967,496b    | 12.296μs    | 12.566μs    | 12.421μs    | 13.015μs    | 0.239μs  | 1.90%  | +348.70%    |
| FetchNewServicesBench       | benchBuildRecursiveFactoryAlias1 |       | []     | 1000 | 10  | 967,496b    | 12.272μs    | 12.825μs    | 13.105μs    | 13.331μs    | 0.356μs  | 2.77%  | +357.96%    |
| FetchNewServicesBench       | benchFetchRecursiveFactoryAlias2 |       | []     | 1000 | 10  | 967,496b    | 12.286μs    | 12.649μs    | 12.569μs    | 13.152μs    | 0.271μs  | 2.15%  | +351.68%    |
| FetchNewServicesBench       | benchBuildRecursiveFactoryAlias2 |       | []     | 1000 | 10  | 967,496b    | 12.125μs    | 12.582μs    | 12.716μs    | 13.166μs    | 0.340μs  | 2.71%  | +349.27%    |
| FetchNewServicesBench       | benchFetchAbstractFactoryFoo     |       | []     | 1000 | 10  | 967,488b    | 12.851μs    | 13.358μs    | 13.600μs    | 13.813μs    | 0.351μs  | 2.63%  | +376.99%    |
| FetchNewServicesBench       | benchBuildAbstractFactoryFoo     |       | []     | 1000 | 10  | 967,488b    | 12.266μs    | 12.705μs    | 12.633μs    | 13.135μs    | 0.295μs  | 2.33%  | +353.65%    |
| SetNewServicesBench         | benchSetFactory                  |       | []     | 1000 | 10  | 992,128b    | 12.394μs    | 12.755μs    | 12.657μs    | 13.189μs    | 0.237μs  | 1.86%  | +355.45%    |
| SetNewServicesBench         | benchSetAlias                    |       | []     | 1000 | 10  | 992,128b    | 28.579μs    | 29.372μs    | 29.209μs    | 30.831μs    | 0.590μs  | 2.01%  | +948.80%    |
| SetNewServicesBench         | benchSetAliasOverrided           |       | []     | 1000 | 10  | 992,136b    | 76.288μs    | 77.842μs    | 77.077μs    | 81.144μs    | 1.435μs  | 1.84%  | +2,679.58%  |
+-----------------------------+----------------------------------+-------+--------+------+-----+-------------+-------------+-------------+-------------+-------------+----------+--------+-------------+

After:

+-----------------------------+----------------------------------+-------+--------+------+-----+-------------+-------------+-------------+-------------+-------------+----------+--------+-------------+
| benchmark                   | subject                          | group | params | revs | its | mem         | best        | mean        | mode        | worst       | stdev    | rstdev | diff        |
+-----------------------------+----------------------------------+-------+--------+------+-----+-------------+-------------+-------------+-------------+-------------+----------+--------+-------------+
| FetchCachedServicesBench    | benchFetchFactory1               |       | []     | 1000 | 20  | 963,704b    | 2.727μs     | 2.858μs     | 2.847μs     | 2.983μs     | 0.064μs  | 2.25%  | +7.11%      |
| FetchCachedServicesBench    | benchFetchInvokable1             |       | []     | 1000 | 20  | 963,704b    | 2.577μs     | 2.705μs     | 2.689μs     | 2.829μs     | 0.081μs  | 3.00%  | +1.38%      |
| FetchCachedServicesBench    | benchFetchService1               |       | []     | 1000 | 20  | 963,704b    | 2.597μs     | 2.668μs     | 2.636μs     | 2.766μs     | 0.046μs  | 1.74%  | 0.00%       |
| FetchCachedServicesBench    | benchFetchAlias1                 |       | []     | 1000 | 20  | 963,704b    | 2.597μs     | 2.721μs     | 2.702μs     | 2.852μs     | 0.084μs  | 3.07%  | +1.99%      |
| FetchCachedServicesBench    | benchFetchRecursiveAlias1        |       | []     | 1000 | 20  | 963,712b    | 2.622μs     | 2.725μs     | 2.795μs     | 2.829μs     | 0.079μs  | 2.89%  | +2.13%      |
| FetchCachedServicesBench    | benchFetchRecursiveAlias2        |       | []     | 1000 | 20  | 963,712b    | 2.647μs     | 2.760μs     | 2.725μs     | 2.893μs     | 0.064μs  | 2.31%  | +3.44%      |
| FetchCachedServicesBench    | benchFetchAbstractFactoryService |       | []     | 1000 | 20  | 963,720b    | 12.608μs    | 13.053μs    | 13.206μs    | 13.434μs    | 0.254μs  | 1.94%  | +389.20%    |
| FetchNewServiceManagerBench | benchFetchServiceManagerCreation |       | []     | 100  | 20  | 24,029,952b | 1,699.350μs | 1,733.026μs | 1,720.312μs | 1,790.900μs | 24.906μs | 1.44%  | +64,849.89% |
| FetchNewServicesBench       | benchFetchFactory1               |       | []     | 1000 | 10  | 966,392b    | 12.609μs    | 13.165μs    | 13.185μs    | 13.559μs    | 0.266μs  | 2.02%  | +393.38%    |
| FetchNewServicesBench       | benchBuildFactory1               |       | []     | 1000 | 10  | 966,392b    | 11.787μs    | 12.125μs    | 11.949μs    | 12.514μs    | 0.262μs  | 2.16%  | +354.41%    |
| FetchNewServicesBench       | benchFetchInvokable1             |       | []     | 1000 | 10  | 966,392b    | 13.441μs    | 13.798μs    | 13.877μs    | 14.157μs    | 0.209μs  | 1.51%  | +417.12%    |
| FetchNewServicesBench       | benchBuildInvokable1             |       | []     | 1000 | 10  | 966,392b    | 12.281μs    | 12.605μs    | 12.432μs    | 13.029μs    | 0.256μs  | 2.03%  | +372.42%    |
| FetchNewServicesBench       | benchFetchService1               |       | []     | 1000 | 10  | 966,392b    | 2.810μs     | 2.864μs     | 2.834μs     | 2.958μs     | 0.049μs  | 1.72%  | +7.33%      |
| FetchNewServicesBench       | benchFetchFactoryAlias1          |       | []     | 1000 | 10  | 966,392b    | 11.910μs    | 12.376μs    | 12.187μs    | 12.974μs    | 0.351μs  | 2.84%  | +363.82%    |
| FetchNewServicesBench       | benchBuildFactoryAlias1          |       | []     | 1000 | 10  | 966,392b    | 12.000μs    | 12.354μs    | 12.329μs    | 12.672μs    | 0.176μs  | 1.42%  | +363.01%    |
| FetchNewServicesBench       | benchFetchRecursiveFactoryAlias1 |       | []     | 1000 | 10  | 966,408b    | 11.691μs    | 12.134μs    | 12.277μs    | 12.501μs    | 0.262μs  | 2.16%  | +354.76%    |
| FetchNewServicesBench       | benchBuildRecursiveFactoryAlias1 |       | []     | 1000 | 10  | 966,408b    | 12.137μs    | 12.516μs    | 12.344μs    | 12.971μs    | 0.277μs  | 2.21%  | +369.09%    |
| FetchNewServicesBench       | benchFetchRecursiveFactoryAlias2 |       | []     | 1000 | 10  | 966,408b    | 11.863μs    | 12.326μs    | 12.412μs    | 12.721μs    | 0.295μs  | 2.40%  | +361.95%    |
| FetchNewServicesBench       | benchBuildRecursiveFactoryAlias2 |       | []     | 1000 | 10  | 966,408b    | 11.780μs    | 12.177μs    | 12.138μs    | 12.648μs    | 0.275μs  | 2.26%  | +356.38%    |
| FetchNewServicesBench       | benchFetchAbstractFactoryFoo     |       | []     | 1000 | 10  | 966,400b    | 12.754μs    | 13.143μs    | 12.982μs    | 13.743μs    | 0.311μs  | 2.37%  | +392.58%    |
| FetchNewServicesBench       | benchBuildAbstractFactoryFoo     |       | []     | 1000 | 10  | 966,400b    | 11.730μs    | 12.002μs    | 11.872μs    | 12.480μs    | 0.237μs  | 1.98%  | +349.82%    |
| SetNewServicesBench         | benchSetFactory                  |       | []     | 1000 | 10  | 991,040b    | 11.968μs    | 12.282μs    | 12.419μs    | 12.579μs    | 0.204μs  | 1.66%  | +360.32%    |
| SetNewServicesBench         | benchSetAlias                    |       | []     | 1000 | 10  | 991,040b    | 28.803μs    | 29.834μs    | 29.417μs    | 30.981μs    | 0.703μs  | 2.36%  | +1,018.11%  |
| SetNewServicesBench         | benchSetAliasOverrided           |       | []     | 1000 | 10  | 991,048b    | 74.980μs    | 76.211μs    | 75.839μs    | 78.355μs    | 0.944μs  | 1.24%  | +2,756.22%  |
+-----------------------------+----------------------------------+-------+--------+------+-----+-------------+-------------+-------------+-------------+-------------+----------+--------+-------------+

src/ServiceManager.php

@@ -389,7 +389,7 @@ private function configureAliases(array $aliases)
             return;
         }
 
-        if ($this->mergeIntoArray($this->aliases, $aliases)) {
+        if ($this->mergeNewAliasesIntoOriginalOnes($aliases)) {
             $this->resolveAliases($this->aliases);
 
             return;
@@ -400,31 +400,28 @@ private function configureAliases(array $aliases)
     }
 
     /**
-     * Merge source into destination.
-     * This method has good performance:
-     *  - at empty destination
-     *  - at adding few elements into array
-     *  - at checking arrays keys intersection
-     *
-     * Provide only present intersect
-     *
-     * @param array $destination
      * @param array $source
-     * @return boolean
+     *
+     * @return bool whether any of the aliases got replaced
      */
-    private function mergeIntoArray(array &$destination, array &$source)
+    private function mergeNewAliasesIntoOriginalOnes(array $source)
     {
-        if (empty($destination)) {
-            $destination = $source;
+        if (empty($this->aliases)) {
+            $this->aliases = $source;
+
             return false;
         }
+
         $intersect = false;
+
         foreach ($source as $name => $target) {
-            if (isset($destination[$name])) {
+            if (isset($this->aliases[$name])) {
                 $intersect = true;
             }
-            $destination[$name] = $target;
+
+            $this->aliases[$name] = $target;
         }
+
         return $intersect;
     }