About adding a new filed to a struct in primnodes.h

Hi:

For example, we added a new field in a node in primnodes.h

struct FuncExpr
{

+ int newf;
};

then we modified the copy/read/out functions for this node. In
_readFuncExpr,
we probably add something like

static FuncExpr
_readFuncExpr(..)
{
..
+ READ_INT_FILED(newf);
};

Then we will get a compatible issue if we create a view with the node in
the older version and access the view with the new binary. I think we can
have bypass this issue easily with something like

READ_INT_FIELD_UNMUST(newf, defaultvalue);

However I didn't see any code like this in our code base. does it doesn't
work or is it something not worth doing?

--
Best Regards
Andy Fan