Incorrect behavior of ConsecutiveNullCompareReturnsToNullCoalesceQueueRector

[jlherren]

Bug Report

Subject	Details
Rector version	last dev-main
Installed as	composer dependency

Minimal PHP Code Causing Issue

See https://getrector.com/demo/8420e8f2-769b-453b-b2cb-b4289a8cb15c

<?php

class MyClass {
    protected ?stdClass $prop1 = null;
    protected ?stdClass $prop2 = null;

    public function getProp(): stdClass {
        if ($this->prop1 !== null) {
            return $this->prop1;
        }
        if ($this->prop2 !== null) {
            return $this->prop2;
        }
        throw new RuntimeException('No prop is set');
    }
}

Responsible rules

• ConsecutiveNullCompareReturnsToNullCoalesceQueueRector

Expected Behavior

Desired behavior is either to do nothing at all, or transform to something like the following (throw expression requires PHP 8):

    public function getProp(): stdClass {
        return $this->prop1 ?? $this->prop2 ?? throw new RuntimeException('No prop is set');
    }

[jlherren]

@samsonasik Thanks, that was fast! :)

However, I found two more cases that still fail (main@fe33aa). I can't use the demo site, because it hasn't been updated yet.

It creates two return statements here:

--- Expected
+++ Actual
@@ @@
 
     public function getProp(): \stdClass
     {
-        if ($this->prop1 !== null) {
-            return $this->prop1;
-        }
-        if ($this->prop2 !== null) {
-            return $this->prop2;
-        }
         return new \stdClass();
+        return $this->prop1 ?? $this->prop2;
     }
 }

And ignores that there's a side effects here:

     public function getProp(): ?\stdClass
     {
-        if ($this->prop1 !== null) {
-            return $this->prop1;
-        }
-        if ($this->prop2 !== null) {
-            return $this->prop2;
-        }
         echo "Hi!\n";
-        return null;
+        return $this->prop1 ?? $this->prop2;
     }

[samsonasik]

Ok, reopen, I will check when I have a chance. Feel free to provide a patch first if you can ;)