GraphDependencies and completion

[Vicente-Arturo Romero-Zaldivar]

On 10/16/2015 12:03 PM, Andreas Lundblad wrote:
> On Fri, Oct 16, 2015 at 09:55:54AM -0700, Vicente-Arturo Romero-Zaldivar wrote:
>> Hi,
>>
>> On 10/16/2015 03:24 AM, Andreas Lundblad wrote:
>>> Widening the audience of this discussion. Jan and Maurizio, forgive the overlap with previous email.
>>>
>>> I've looked into the Dependencies class and tried to figure out how it can be adjusted to cover the requirements of sjavac (with the help of Jan and Maurizio). A summary follows.
>>>
>>> Currently the Dependencies mechanism works as follows: When a symbol is about to be completed, it's pushed onto a stack and when completion finishes the stack is popped.
>> Where is this stack living? According to this description this
>> algorithm is trying to find a topological sort of the dependency
>> graph but it seems like its logic is not explicit but interleaved
>> with the completion process. Probably this is the only way to do it.
>> Can you provide some links to the current code implementing this?
> The stack lives in Dependencies.java (in the GraphDependencies class to be specific).
>
> In a sense symbols are completed in a topological sorted order I guess, but note that completion of A may trigger completion of B which in turn may trigger completion of A again. This would mean that A depends on B and B depends on A. That is, the resulting dependency relation is not a topological sorted sequence, but an arbitrary graph.
>
> You are right that the algorithm is interleaved with the completion process. Previously I analyzed the trees explicitly after the compilation, but it was more code and more cases to cover. Dependencies.java was already there for another purpose, so I switched to that which simplified the code a lot. As discovered later it introduced this regression.

Is it possible to just "observe" the process, gathering the needed 
information and build the graph you need once the process finishes?

Vicente
>
> -- Andreas