Long if statements and PSR-2

How about making it a one-liner to avoid that problem and make the statement more readable:

$blockModeIsHidevar = $field->getBlockMode() == FieldInterface::BLOCK_MODE_HIDEVAR;$blockNotEnabled = !isset($this->enabledBlocks[$field->getBlock()]);if ($blockModeIsHidevar && $blockNotEnabled) {}

Alternative:

I usually do it with methods, this could looke like that:

if ($this->blockModeIsHidevar($field) && $this->blockNotEnabled($field)) {}// ...private function blockModeIsHidevar($field){    return $field->getBlockMode() == FieldInterface::BLOCK_MODE_HIDEVAR}private function blockNotEnabled($field){    return !isset($this->enabledBlocks[$field->getBlock()])}

This way, the optimization of && still takes place.

Extract it into shorter boolean expressions first, then use those variables in your if() statement.

ie:

$hideVarMode = $field->getBlockMode() === FieldInterface::BLOCK_MODE_HIDEVAR;$enabledBlock = !isset($this->enabledBlocks[$field->getBlock()];if($hideVarMode && $enabledBlock) {    ....}

(note, I also turned your first test into a triple-equal, since this is likely to be better; feel free to change it back if that doesn't work for you)