[perl #45695] [PATCH] Remove seemingly unnecessary Parrot_cont->from_ctx

[Will Coleda via RT]

On Sun Sep 23 11:19:14 2007, bgeron at gmail.com wrote:
> Parrot_cont (the internal structure storing info about
> (Ret)Continuations) has two fields 'to_ctx' and 'from_ctx'. 'to_ctx'
> stores the context that should be active after invoking the
> Continuation, but I don't know what 'from_ctx' is supposed to hold 
(the
> context it was made in? the context it was called from?)
> 
> To test if 'from_ctx' is redundant, I tried removing the field and all
> accesses to it, and no extra tests failed (see patch). I think we can
> safely remove the field, if nobody objects.
> 
> The patch slightly modifies invalidate_retc_context (which makes sure 
we
> don't get a Continuation that continues to a RetContinuation, that 
would
> be illegal) to explicitly end the loop when we get to the topmost
> context. If it wouldn't, Parrot segfaults with from_ctx removed.

Rejecting patch, based on Patrick Michaud's recent delving into 
continutation guts - turns out we do need the from_ctx. Patrick says, 
"at present, it's the only way for a continuation to know its current 
context."

Thanks for the patch, though!

-- 
Will "Coke" Coleda