[Scons-users] Wacky crash in Clone()

[Marc Branchaud]

On 2022-01-25 14:57, Bill Deegan wrote:
> Can you be more specific about what info an action would want to change 
> with the builder?
> More details = possible expert help on how to implement it in a "safe" way..

Recall that I have a "BaseBuilder" and a "MyBuilder" that extends/adapts 
it (I'm omitting the generate() and exists() functions):

	site_scons/BaseBuilder.py
	    def builder(target, source, env):
	        # Do some bookkeeping, then run the build command:
	        subprocess.call( ... )

	site_scons/site_tools/MyBuilder.py
	    import BaseBuilder
	    def builder(target, source, env):
	        # Set up stuff for the BaseBuilder, then run it.
	        return BaseBuilder.builder(target, source, env)

MyBuilder wants to do things like add extra options and/or set shell 
environment variables for the command run by the BaseBuilder.

There is also a "PlainBuilder" that just invokes the BaseBuilder 
directly (I did not show this in my original message):

	site_scons/site_tools/PlainBuilder.py
	    import BaseBuilder

	    def generate(env, **kwargs):
	        env['BUILDERS']['PlainBuilder'] = env.Builder(
	            action = env.Action(
	                BaseBuilder.builder,
	                BaseBuilder.message,
	            )
	        )

Invocations of PlainBuilder will themselves set their own options and/or 
shell variables for the command.

Whatever MyBuilder sets up for BaseBuilder should not pollute 
PlainBuilder invocations of BaseBuilder.

In SCons 2.x I did this by cloning the build environment inside 
MyBuilder and tweaking the clone as needed.

In SCons 4.x I changed this to use a module-level "overrides" dict 
inside BaseBuilder.py.

(Sorry for the slow replay.  After I managed to fix my problem, $work 
priorities took over.)

		M.