Fixes as per review.

Author: dereuromark

src/Propel/Common/Config/Loader/FileLoader.php

@@ -66,7 +66,7 @@ public function __construct(FileLocatorInterface $locator = null)
     public function resolveParams(array $configuration)
     {
         if ($this->resolved) {
-            return $configuration;
+            return [];
         }
 
         $this->config = $configuration;

src/Propel/Generator/Builder/Om/AbstractOMBuilder.php

@@ -982,7 +982,7 @@ public function applyBehaviorModifierBase($hookName, $modifier, &$script, $tab =
      * Checks whether any registered behavior content creator on that table exists a contentName
      * @param string $contentName The name of the content as called from one of this class methods, e.g. "parentClassName"
      * @param string $modifier    The name of the modifier object providing the method in the behavior
-     * @return mixed
+     * @return string|null
      */
     public function getBehaviorContentBase($contentName, $modifier)
     {
@@ -993,6 +993,8 @@ public function getBehaviorContentBase($contentName, $modifier)
                 return $modifier->$contentName($this);
             }
         }
+
+        return null;
     }
 
     /**

src/Propel/Generator/Builder/Om/AbstractObjectBuilder.php

@@ -202,7 +202,7 @@ public function applyBehaviorModifier($hookName, &$script, $tab = "        ")
     /**
      * Checks whether any registered behavior content creator on that table exists a contentName
      * @param string $contentName The name of the content as called from one of this class methods, e.g. "parentClassName"
-     * @return mixed
+     * @return string|null
      */
     public function getBehaviorContent($contentName)
     {

src/Propel/Generator/Builder/Om/ExtensionQueryBuilder.php

@@ -121,6 +121,7 @@ public function applyBehaviorModifier($hookName, &$script, $tab = "        ")
     /**
      * Checks whether any registered behavior content creator on that table exists a contentName
      * @param string $contentName The name of the content as called from one of this class methods, e.g. "parentClassName"
+     * @return string|null
      */
     public function getBehaviorContent($contentName)
     {

src/Propel/Generator/Builder/Om/QueryBuilder.php

@@ -1791,6 +1791,7 @@ public function applyBehaviorModifier($hookName, &$script, $tab = "        ")
     /**
      * Checks whether any registered behavior content creator on that table exists a contentName
      * @param string $contentName The name of the content as called from one of this class methods, e.g. "parentClassName"
+     * @return string|null
      */
     public function getBehaviorContent($contentName)
     {

tests/Propel/Tests/Common/Config/Loader/FileLoaderTest.php

@@ -56,8 +56,8 @@ public function resolveParamsProvider()
                 '->resolve() supports % escaping by doubling it'
             ],
             [
-                ['foo'=>'bar', 'foo' => ['bar' => ['ding' => 'I\'m a bar %%foo %%bar']]],
-                ['foo'=>'bar', 'foo' => ['bar' => ['ding' => 'I\'m a bar %foo %bar']]],
+                ['foo' => ['bar' => ['ding' => 'I\'m a bar %%foo %%bar']]],
+                ['foo' => ['bar' => ['ding' => 'I\'m a bar %foo %bar']]],
                 '->resolve() supports % escaping by doubling it'
             ],
             [
@@ -315,15 +315,15 @@ public function testParameterIsNotStringOrNumber()
         $this->loader->resolveParams($config);
     }
 
-    public function testCallResolveParamTwiceReturnNull()
+    public function testCallResolveParamTwiceReturnsEmpty()
     {
         $config = [
             'foo' => 'bar',
             'baz' => '%foo%'
         ];
 
         $this->assertEquals(['foo' => 'bar', 'baz' => 'bar'], $this->loader->resolveParams($config));
-        $this->assertNull($this->loader->resolveParams($config));
+        $this->assertSame([], $this->loader->resolveParams($config));
     }
 }