Feature suggestion: Produce a warning when a user supplied config selector cannot be applied because a higher priority selector is in affect.

[mahesh-panchal]

New feature

Produce a warning when a custom config cannot override an existing setting.

some config hidden in the depths of the pipeline:

process {
    withName: '*:SUBWORKFLOW:(TOOL1|TOOL2)' {
         cpu = { some optimization code }
         memory = { some optimization code }
    }
}  

but then the user gets an error and tries to increase resources

process {
    withName: 'TOOL1' {
        memory = 50.GB
    }
}

The problem is, this is silently not applied because the full name ( in the pipeline ) has a higher priority than the simple name ( user config ).

Use case

The use case is for when errors occur and users try to increase resources but it silently fails confusing users further when they think they've given enough resources, and aren't familiar enough with config selector priority.

Suggested implementation

I don't know anything about how configs are applied to give an implementation suggestion.

[OlivierCoen]

Hi,
I confirm that not knowing which config is actually used during a run is quite cumbersome.
Having warning messages for configs that got ignored would really help :)
Thanks in advance!

[OlivierCoen]

Or perhaps adding a nextflow argument -preview-config, to visualise beforehand which config is going to be used process by process?
Thanks a lot

[mahesh-panchal]

There's the nextflow config command that will do that. It also has the -value option to print out a specific value. The average user though will not likely query the config before running. However I think it doesn't take custom configs so it's not a fully functional option for checking a final config.

[OlivierCoen]

Hum that's very useful, I did not know one could do that, thanks.
Anyway, I totally agree with you, there should be warning messages every time a custom config cannot be fully taken into account