Fixes the null directory generation when --help is used

Author: baldikacti

nextflow.config

@@ -109,21 +109,24 @@ manifest {
     version         = '0.1.0'
 }
 
+// Generates execution reports
 def trace_timestamp = new java.util.Date().format( 'yyyy-MM-dd_HH-mm-ss')
+// Only enable reports if not showing help and output_dir is set
+def enableReports = !params.help && params.output_dir != null
 timeline {
-    enabled = true
+    enabled = enableReports
     file    = "${params.output_dir}/pipeline_info/execution_timeline_${trace_timestamp}.html"
 }
 report {
-    enabled = true
+    enabled = enableReports
     file    = "${params.output_dir}/pipeline_info/execution_report_${trace_timestamp}.html"
 }
 trace {
-    enabled = true
+    enabled = enableReports
     file    = "${params.output_dir}/pipeline_info/execution_trace_${trace_timestamp}.txt"
 }
 dag {
-    enabled = true
+    enabled = enableReports
     file    = "${params.output_dir}/pipeline_info/pipeline_dag_${trace_timestamp}.html"
 }