Include module statement inside a conditional statement throws error when run as a subworkflow

[JoseEspinosa]

Bug report

Expected behavior and actual behavior

When a module include is in a conditional statement it gives an exception if it's run as a subworkflow but not it is run as the main.

Steps to reproduce the problem

I created this repo to reproduce the issue.

If this script is run as the main it works.

git clone https://github.com/JoseEspinosa/nxf_issue_conditional_include.git
cd workflows/
nextflow run my_pipeline.nf

However, if it is run from the parent directory with this script then it throws an exception.

cd..
nextflow run main.nf

The problem is on this line which has an include inside the if statement. But the behavior is not consistent when running it as a subworkflow or as the main script.

Program output

N E X T F L O W  ~  version 21.04.0
Launching `main.nf` [condescending_mahavira] - revision: 71cf30c291
No such file: Can't find a matching module file for include: ./modules/foo/main.nf

 -- Check script './workflows/my_pipeline.nf' at line: 10 or see '.nextflow.log' file for more details

nextflow.log

Environment

• Nextflow version: [21.04.0 build 5552]
• Java version: [1.8.0_65]
• Operating system: [macOS]
• Bash version: (use the command $SHELL --version)[GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin19)]

[pditommaso]

Include should not go into workflow. This is not expected to be supported in any way.

[JoseEspinosa]

The snipped below works, it is ok or it would be better just to have the include outside any conditional closure?

if (!params.skip_foo) {
    include { FOO } from './modules/foo/main.nf'
}

workflow MY_PIPELINE {    
      
     if (!params.skip_foo) {
         FOO()               
     }
}

[pditommaso]

Just killed this 7dbf64b. Thanks Jose for reporting.