[MySQL] Generated invalid PLPGSQL preserves SET in some nested blocks

[ssherwood]

Running Voyager to migrate a set of stored procedures from MySQL (MariaDB 10.5) and identified a syntax issue where some nested blocks case assignments with set not be translated.

Original:

...
   IF Auth <> "" THEN
   	 set Auth=concat(Intro,URL,Header,Username,Slash,Header,
   		 Password, Slash, Header, ContentType, Slash,
   		 Data, char(34),DataRaw, char(34),Slash);    
    END IF;
...

Results:

...
   IF Auth <> '' THEN
   	 set Auth=concat(Intro,URL,Header,Username,Slash,Header,
   		 Password, Slash, Header, ContentType, Slash,
   		 Data, array_to_string(ARRAY(SELECT chr(unnest(34))),''),DataRaw, array_to_string(ARRAY(SELECT chr(unnest(34))),''),Slash);
   END IF;  
...

Something is causing the assignment (:=) from being applied and the set is retained causing a syntax error. I.e. ```

AuthJson := concat(...

Also the translation of char(34) to array_to_string(ARRAY(SELECT chr(unnest(34))),'') seems particularly verbose.