context: Cleanup is_null() checks and irrelevant else code paths

This class specifically has these 2 things in many cases and converts
into the use of a tenary operations.

Quoting @Thiemo_WMDE from Gerrit comment: "The ?: operator will skip
empty arrays, empty strings, as well as the string "0". But this is
not a problem here because the properties under test are all objects.
Objects are always considered true in PHP."

Sample change can be seen below as, from;
```
if ( !is_null( $this->skin )) {
    return $this->skin;
} else {
    return $this->getContext()->getSkin();
}

```

to

```
return $this->skin ?: $this->getContext()->getSkin();
```

Change-Id: I377b118d86a24c7bcb15512f6714e6201a3e36ee

diff --git a/includes/context/DerivativeContext.php b/includes/context/DerivativeContext.php
index 9817c3f..d32617e 100644 (file)
--- a/includes/context/DerivativeContext.php
+++ b/includes/context/DerivativeContext.php
@@ -91,11 +91,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return Config
         */
        public function getConfig() {
-               if ( !is_null( $this->config ) ) {
-                       return $this->config;
-               } else {
-                       return $this->getContext()->getConfig();
-               }
+               return $this->config ?: $this->getContext()->getConfig();
        }
 
        /**
@@ -111,11 +107,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return Timing
         */
        public function getTiming() {
-               if ( !is_null( $this->timing ) ) {
-                       return $this->timing;
-               } else {
-                       return $this->getContext()->getTiming();
-               }
+               return $this->timing ?: $this->getContext()->getTiming();
        }
 
        /**
@@ -129,11 +121,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return WebRequest
         */
        public function getRequest() {
-               if ( !is_null( $this->request ) ) {
-                       return $this->request;
-               } else {
-                       return $this->getContext()->getRequest();
-               }
+               return $this->request ?: $this->getContext()->getRequest();
        }
 
        /**
@@ -147,11 +135,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return Title|null
         */
        public function getTitle() {
-               if ( !is_null( $this->title ) ) {
-                       return $this->title;
-               } else {
-                       return $this->getContext()->getTitle();
-               }
+               return $this->title ?: $this->getContext()->getTitle();
        }
 
        /**
@@ -165,11 +149,13 @@ class DerivativeContext extends ContextSource implements MutableContext {
        public function canUseWikiPage() {
                if ( $this->wikipage !== null ) {
                        return true;
-               } elseif ( $this->title !== null ) {
+               }
+
+               if ( $this->title !== null ) {
                        return $this->title->canExist();
-               } else {
-                       return $this->getContext()->canUseWikiPage();
                }
+
+               return $this->getContext()->canUseWikiPage();
        }
 
        /**
@@ -190,11 +176,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return WikiPage
         */
        public function getWikiPage() {
-               if ( !is_null( $this->wikipage ) ) {
-                       return $this->wikipage;
-               } else {
-                       return $this->getContext()->getWikiPage();
-               }
+               return $this->wikipage ?: $this->getContext()->getWikiPage();
        }
 
        /**
@@ -208,11 +190,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return OutputPage
         */
        public function getOutput() {
-               if ( !is_null( $this->output ) ) {
-                       return $this->output;
-               } else {
-                       return $this->getContext()->getOutput();
-               }
+               return $this->output ?: $this->getContext()->getOutput();
        }
 
        /**
@@ -226,11 +204,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return User
         */
        public function getUser() {
-               if ( !is_null( $this->user ) ) {
-                       return $this->user;
-               } else {
-                       return $this->getContext()->getUser();
-               }
+               return $this->user ?: $this->getContext()->getUser();
        }
 
        /**
@@ -255,11 +229,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @since 1.19
         */
        public function getLanguage() {
-               if ( !is_null( $this->lang ) ) {
-                       return $this->lang;
-               } else {
-                       return $this->getContext()->getLanguage();
-               }
+               return $this->lang ?: $this->getContext()->getLanguage();
        }
 
        /**
@@ -274,11 +244,7 @@ class DerivativeContext extends ContextSource implements MutableContext {
         * @return Skin
         */
        public function getSkin() {
-               if ( !is_null( $this->skin ) ) {
-                       return $this->skin;
-               } else {
-                       return $this->getContext()->getSkin();
-               }
+               return $this->skin ?: $this->getContext()->getSkin();
        }
 
        /**