[Scons-users] Wacky crash in Clone()

[Marc Branchaud]

On 2022-01-24 17:06, Bill Deegan wrote:
> So you just want CCFLAGS to be overwritten in the action? (or is this
> just an example?)

Not CCFLAGS, but variables that affect the behaviour of the BaseBuilder. 
  These should not retain their values after the invocation of the 
Builder, so stuffing them into a cloned Environment was convenient.  (My 
example showed the Clone() call in message(), but it was also happening 
in the builder() function.)

This code is over 10 years old, and I think it would be implemented very 
differently today -- not just to avoid Cloning inside an Action.  But a 
major refactoring is beyond the scope at this time.

> If you can be specific about what you want to override with your
> Clone(), I'd be there's another way to accomplish that than the Clone()..
>
> It may just be more advanced SCons-Fu.. :)
I rewrote things to avoid cloning Environments, and now all is joy -- 
thanks for the pointer!

For future spelunkers, my solution is a bit hacky:  I taught the 
BaseBuilder to drive its behaviour from a combination of the Environment 
and a module-level "overrides" dict.  The MyBuilder sets what it needs 
in BaseBuilder.overrides, and BaseBuilder.builder() clears the overrides 
when it's done.

Thanks again!

		M.