test: improve reverse reference resolution handling

src/csv-loader/loader.ts

@@ -802,25 +802,10 @@ export function parseCsv(
     relax_column_count: true,
   });
 
-  if (records.length < 2) {
-    throw new Error("CSV must have at least 2 rows: headers and schemas");
-  }
-
-  const headers = records[0];
-  const schemas = records[1];
-
-  if (headers.length !== schemas.length) {
-    throw new Error(
-      `Header count (${headers.length}) does not match schema count (${schemas.length})`,
-    );
-  }
-
-  // Parse reverse reference declarations from comment lines between schema row and data rows
+  // Filter out comment lines from all records, collecting reverse reference declarations
   const reverseReferences: ReverseReferenceDeclaration[] = [];
-  const dataRows: string[][] = [];
-  for (let i = 2; i < records.length; i++) {
-    const row = records[i];
-    // Check if this is a comment line (starting with the configured comment character)
+  const filteredRecords: string[][] = [];
+  for (const row of records) {
     const firstCell = (row[0] ?? "").trim();
     if (comment && firstCell.startsWith(comment)) {
       const decl = parseReverseReferenceDeclaration(firstCell, comment);
@@ -830,9 +815,24 @@ export function parseCsv(
       // Skip comment lines (whether or not they're reverse ref declarations)
       continue;
     }
-    dataRows.push(row);
+    filteredRecords.push(row);
   }
 
+  if (filteredRecords.length < 2) {
+    throw new Error("CSV must have at least 2 rows: headers and schemas");
+  }
+
+  const headers = filteredRecords[0];
+  const schemas = filteredRecords[1];
+
+  if (headers.length !== schemas.length) {
+    throw new Error(
+      `Header count (${headers.length}) does not match schema count (${schemas.length})`,
+    );
+  }
+
+  const dataRows = filteredRecords.slice(2);
+
   // Also check schema row cells for comment-prefixed reverse reference declarations
   // (in case they appear as schema cells rather than separate rows)
   for (let col = 0; col < schemas.length; col++) {