ma/nextflow/docs/reference/feature-flags.md

(config-feature-flags)=

Feature flags

Feature flags enable opt-in features. They must be specified in the pipeline script.

:::{warning} Feature flags marked as preview can cause pipelines run with newer versions of Nextflow to fail due to breaking changes. Always consult the {ref}migration notes <migrations-page> before updating to a new Nextflow version. :::

nextflow.enable.configProcessNamesValidation

:::{deprecated} 25.10.0 Use the {ref}strict syntax <strict-syntax-page> instead. It validates process selectors without producing false warnings. :::

When true, prints a warning for every withName: process selector that doesn't match a process in the pipeline (default: true).

nextflow.enable.dsl

:::{deprecated} 25.04.0 :::

Defines the DSL version to use (1 or 2).

nextflow.enable.moduleBinaries

When true, enables the use of module-scoped executable scripts via {ref}module resources <module-resources>.

nextflow.enable.strict

:::{deprecated} 26.04.0 :::

When true, executes the pipeline in "strict" mode, which introduces the following rules:

• When reading a params file, Nextflow will fail if a dynamic param value references an undefined variable

• When merging params from a config file with params from the command line, Nextflow will fail if a param is specified from both sources but with different types

• When using the join operator, the failOnDuplicate option is true regardless of any user setting

• When using the join operator, the failOnMismatch option is true (unless remainder is also true) regardless of any user setting

• When using the publishDir process directive, the failOnError option is true regardless of any user setting

• In a process definition, Nextflow will fail if an input or output tuple has only one element

• In a process definition, Nextflow will fail if an output emit name is not a valid identifier (i.e. it should match the pattern /[A-Za-z_][A-Za-z0-9_]*/)

• During a process execution, Nextflow will fail if a received input tuple does not have the same number of elements as was declared

• During a process execution, Nextflow will fail if the storeDir directive is used with non-file outputs

• Nextflow will fail if a pipeline param is referenced before it is defined

• Nextflow will fail if multiple functions and/or processes with the same name are defined in a module script

nextflow.enable.types

:::{versionadded} 26.04.0 :::

Preview feature: the syntax and behavior may change in future releases.

When true, enables the use of {ref}typed processes <process-typed-page> and {ref}typed workflows <workflow-typed-page>. Must be enabled in every script that uses typed processes/workflows. Legacy processes/workflows cannot be defined in scripts with this flag enabled.