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Carsonbot

Looking at https://docs.docker.com/compose/compose-file/13-merge/#replace-value, they use a yaml tag for this.
Is that something we could do also?

Hi @nicolas-grekas 🙋🏼‍♂️,

thanks for looking at my PR :). I believe we're able to handle it similarly. My way was easier and universal across all config formats. In such way, we should handle it like:

YAML:

#...
from: !override
	- from_a
	- from_b

PHP:

	->override()

XML:

	<... override="true">

I'll try to implement this 🧐.

The merging happens during the processing of the configuration in the DI extension (based on the Configuration class). So it would be hard to use such Yaml tags for that.

I would say that from places for a workflow transition should never be merged between different files redefining the transition, which would be doable by using the ->performNoDeepMerging() in the Configuration class. In the old days of Symfony, we were careful about where merging should happen in our configuration and where it should be disabled. I have the feeling that this was less considered in more recent times, which means we should probably review our Configuration to identify places where deep merging does not make sense.