Set ch_hgnc_ids default value (#507)

* Update nallo.nf

* changelog

CHANGELOG.md

@@ -95,6 +95,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [#502](https://github.com/genomic-medicine-sweden/nallo/pull/502) - Changed output documentation and structure to match `sample` and `family` for all variants
 - [#502](https://github.com/genomic-medicine-sweden/nallo/pull/502) - Changed the way of validating the samplesheet to remove outputing false errors with `ifEmpty`
 - [#506](https://github.com/genomic-medicine-sweden/nallo/pull/506) - Updated documentation
+- [#507](https://github.com/genomic-medicine-sweden/nallo/pull/507) - Changed the default value of `ch_hgnc_ids` to allow running without `--filter_variants_hgnc_ids` introduced in [#496](https://github.com/genomic-medicine-sweden/nallo/pull/443)
 
 ### `Removed`
 

workflows/nallo.nf

@@ -101,7 +101,7 @@ workflow NALLO {
     // Channels from (optional) input samplesheets validated by schema
     ch_databases                 = createReferenceChannelFromSamplesheet(params.echtvar_snv_databases, 'assets/schema_snp_db.json')
     ch_vep_plugin_files          = createReferenceChannelFromSamplesheet(params.vep_plugin_files, 'assets/schema_vep_plugin_files.json', Channel.value([]))
-    ch_hgnc_ids                 = createReferenceChannelFromSamplesheet(params.filter_variants_hgnc_ids, 'assets/schema_hgnc_ids.json')
+    ch_hgnc_ids                  = createReferenceChannelFromSamplesheet(params.filter_variants_hgnc_ids, 'assets/schema_hgnc_ids.json', Channel.value([]))
         .map { it[0].toString() } // only one element per row
         .collectFile(name: 'hgnc_ids.txt', newLine: true, sort: true)
         .map { file -> [ [ id: 'hgnc_ids' ], file ] }