of course, deactivation with an optinal parameter,
like
var_dump($megaobject,TRUE);

hah, just found out that get_object_vars() doesn?t work with circular references too... very bad

summary, using circular references very much makes scripts very hard (impossible) to debug because of this bug.
You?ll have to kill all circular references to be able to debug objects, depending on number of CRs it?s perhaps no trivial task cos there?s no function like get_object_references() to be able to kill them

so var_dump() supports multiple variables, then perhaps
svar_dump() for safe var dump or any other name

maybe get_object_vars() can get this second SAFETY parameter....

maybe I was too fast... get_object_vars() of course works with circular references, but again var_dump()ing them does not work, it has nothing to do with get_object_vars()...

If someone takes the task designing a new svar_dump() or similar (custom_dump()), we could add two parameters.
param 1) steps, how many steps to resolve, unset=all (as it is currently),1=one level, 2=two levels etc.
we would catch the issue that var_dump() produces never ending output with that too, but It?ll be even better to have both, thus...
param 2) do not resolve references

That?s significant added value and could make debugging a lot easier....

example step=2,no_resolve=TRUE
object(a)(3) { ["a"]=> int(0) ["b"]=> array(3) {
  ["a"]=> array(24)
  ["b"]=> array(14) 
  ["a"]=> array(7) } ["c"]=> &object(circular) (20) }
// "c" does not get expanded, because of no_resolve...

example step=1,no_resolve=FALSE
object(a)(3) { ["a"] int(0) ["b"]=> array(3) ["c"]=> &object(circular) (1) { ["x"] => &object(a) (3) } }

example step=0,no_resolve=TRUE 
// no resolve doesn?t matter here
object(a)(3) { ["a"] int(0) ["b"]=> array(3) ["c"]=> &object(circular) (1) }

Please comment, If anything thinks that?s a good/bad idea...

var_dump() cannot be extended in such a way since it currently dumps the every value passed to it. Thefefore it will break BC. var_dump() currently works better with circular references than before - does not crash.