Add unit test for invalid workflow entry name error handling (#6409)

Signed-off-by: Paolo Di Tommaso <paolo.ditommaso@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Ben Sherman <bentshermann@gmail.com>

Author: 3 people

modules/nextflow/src/main/groovy/nextflow/script/ScriptMeta.groovy

@@ -256,7 +256,7 @@ class ScriptMeta {
         final result = new HashSet(definitions.size() + imports.size())
         // local definitions
         for( def item : definitions.values() ) {
-            if( item instanceof WorkflowDef && item.name != null )
+            if( item instanceof WorkflowDef && item.name )
                 result.add(item.name)
         }
         // processes from imports

modules/nextflow/src/test/groovy/nextflow/script/ScriptDslTest.groovy

@@ -626,4 +626,22 @@ class ScriptDslTest extends Dsl2Spec {
         e2.message == 'Missing process or function Channel.doesNotExist()'
     }
 
+    def 'should show proper error message for invalid entry name' () {
+        when:
+        // Use dsl_eval with an invalid entry name to trigger the error
+        dsl_eval('invalidEntry', '''
+        workflow validWorkflow {
+          /println 'valid'/
+        }
+        
+        workflow {
+          /println 'default'/
+        }
+        ''')
+        
+        then:
+        def err = thrown(IllegalArgumentException)
+        err.message.contains('Unknown workflow entry name: invalidEntry')
+    }
+
 }