Fix validator screaming about new columns

internal/topdata/topdata.go

@@ -432,10 +432,14 @@ func validateDataObject(path string, obj map[string]any, report *ValidationRepor
 			validateRowsFile(path, obj, report, false)
 			return
 		}
+		if _, hasColumns := obj["columns"]; hasColumns {
+			validateColumnsFile(path, obj, report)
+			return
+		}
 		report.Diagnostics = append(report.Diagnostics, Diagnostic{
 			Severity: SeverityWarning,
 			Path:     path,
-			Message:  "module file does not use a recognized canonical shape yet; expected one of entries, overrides, or rows",
+			Message:  "module file does not use a recognized canonical shape yet; expected one of columns, entries, overrides, or rows",
 		})
 		return
 	}
@@ -832,17 +836,44 @@ func validateRowsFile(path string, obj map[string]any, report *ValidationReport,
 	if rowsList, ok := rows.([]any); ok {
 		validateRowCollection(path, obj, rowsList, report)
 	}
-	if columns, ok := obj["columns"]; ok {
-		if list, ok := columns.([]any); !ok {
+	if _, ok := obj["columns"]; ok {
+		validateColumnsFile(path, obj, report)
+	} else if requireColumns {
+		report.Diagnostics = append(report.Diagnostics, Diagnostic{
+			Severity: SeverityError,
+			Path:     path,
+			Message:  "base dataset file must contain columns",
+		})
+	}
+}
+
+func validateColumnsFile(path string, obj map[string]any, report *ValidationReport) {
+	columns, ok := obj["columns"]
+	if !ok {
+		report.Diagnostics = append(report.Diagnostics, Diagnostic{
+			Severity: SeverityError,
+			Path:     path,
+			Message:  "columns file must contain a columns array",
+		})
+		return
+	}
+	list, ok := columns.([]any)
+	if !ok {
 		report.Diagnostics = append(report.Diagnostics, Diagnostic{
 			Severity: SeverityError,
 			Path:     path,
 			Message:  "columns must be a JSON array when present",
 		})
-		} else {
+		return
+	}
 	for _, raw := range list {
 		column, ok := raw.(string)
 		if !ok {
+			report.Diagnostics = append(report.Diagnostics, Diagnostic{
+				Severity: SeverityError,
+				Path:     path,
+				Message:  "columns must contain only strings",
+			})
 			continue
 		}
 		if isAuthoringOnlyField(column) && !preserveLegacyWikiColumnForPath(path, column) {
@@ -854,14 +885,6 @@ func validateRowsFile(path string, obj map[string]any, report *ValidationReport,
 		}
 	}
 }
-	} else if requireColumns {
-		report.Diagnostics = append(report.Diagnostics, Diagnostic{
-			Severity: SeverityError,
-			Path:     path,
-			Message:  "base dataset file must contain columns",
-		})
-	}
-}
 
 func validateEntriesFile(path string, obj map[string]any, report *ValidationReport) {
 	entries, ok := obj["entries"]
@@ -899,6 +922,9 @@ func validateEntriesFile(path string, obj map[string]any, report *ValidationRepo
 			validateInlineTextUsage(path, key, entry, report)
 		}
 	}
+	if _, ok := obj["columns"]; ok {
+		validateColumnsFile(path, obj, report)
+	}
 }
 
 func validateOverridesFile(path string, obj map[string]any, report *ValidationReport) {
@@ -922,6 +948,9 @@ func validateOverridesFile(path string, obj map[string]any, report *ValidationRe
 		container := map[string]any{"rows": overrideList}
 		validateRowCollection(path, container, overrideList, report)
 	}
+	if _, ok := obj["columns"]; ok {
+		validateColumnsFile(path, obj, report)
+	}
 }
 
 func validateStateObject(path string, obj map[string]any, report *ValidationReport) {

internal/topdata/topdata_test.go

@@ -134,6 +134,51 @@ func TestValidateProjectRejectsDuplicateJSONKeys(t *testing.T) {
 	}
 }
 
+func TestValidateProjectAcceptsModuleColumnExpansionFile(t *testing.T) {
+	root := testProjectRoot(t)
+	mkdirAll(t, filepath.Join(root, "topdata", "data", "racialtypes", "core", "modules"))
+	writeFile(t, filepath.Join(root, "topdata", "base_dialog.json"), "{}\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "racialtypes", "core", "base.json"), `{
+  "output": "racialtypes.2da",
+  "columns": ["Label"],
+  "rows": []
+}`+"\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "racialtypes", "core", "modules", "00_newcolumns.json"), `{
+  "columns": ["ECL", "AvailableHeadsMale", "AvailableSkinColors"]
+}`+"\n")
+
+	report := ValidateProject(testProject(root))
+	text := diagnosticsText(report.Diagnostics)
+	if strings.Contains(text, "module file does not use a recognized canonical shape") {
+		t.Fatalf("expected module column expansion file to validate as canonical, got:\n%s", text)
+	}
+	if report.HasErrors() {
+		t.Fatalf("expected module column expansion file to avoid validation errors, got:\n%s", text)
+	}
+}
+
+func TestValidateProjectRejectsInvalidModuleColumnExpansionFile(t *testing.T) {
+	root := testProjectRoot(t)
+	mkdirAll(t, filepath.Join(root, "topdata", "data", "racialtypes", "core", "modules"))
+	writeFile(t, filepath.Join(root, "topdata", "base_dialog.json"), "{}\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "racialtypes", "core", "base.json"), `{
+  "output": "racialtypes.2da",
+  "columns": ["Label"],
+  "rows": []
+}`+"\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "racialtypes", "core", "modules", "00_badcolumns.json"), `{
+  "columns": "ECL"
+}`+"\n")
+
+	report := ValidateProject(testProject(root))
+	if !report.HasErrors() {
+		t.Fatalf("expected invalid module columns file to fail validation, got:\n%s", diagnosticsText(report.Diagnostics))
+	}
+	if !diagnosticsContain(report.Diagnostics, "columns must be a JSON array when present") {
+		t.Fatalf("expected columns array diagnostic, got:\n%s", diagnosticsText(report.Diagnostics))
+	}
+}
+
 func TestValidateProjectRejectsDuplicateEntryKeysAcrossModules(t *testing.T) {
 	root := testProjectRoot(t)
 	mkdirAll(t, filepath.Join(root, "topdata", "data", "baseitems", "modules"))