test: improve reverse reference resolution handling

with reverse references

src/csv-loader/loader.test.ts

@@ -1164,6 +1164,52 @@ describe("parseCsv - reverse reference resolution", () => {
     expect(result.reverseReferences).toHaveLength(1);
     expect(result.data[0]).toHaveProperty("orders");
   });
+
+  it("should handle multiple comment lines including plain comments and reverse references", () => {
+    const orderCsvPath = path.join(fixturesDir, "order.csv");
+    const orderContent = [
+      "id,user,total",
+      "string,string,number",
+      "o01,u01,100",
+      "o02,u01,50",
+      "o03,u02,75",
+    ].join("\n");
+    fs.writeFileSync(orderCsvPath, orderContent);
+
+    try {
+      const csv = [
+        "# id: id of user",
+        "# orders: list of related orders",
+        "# orders := ~order(user)",
+        "id,name",
+        "string,string",
+        "u01,Alice",
+        "u02,Bob",
+      ].join("\n");
+
+      const result = parseCsv(csv, {
+        emitTypes: false,
+        currentFilePath: path.join(fixturesDir, "test.csv"),
+      });
+
+      expect(result.reverseReferences).toHaveLength(1);
+      expect(result.reverseReferences[0].fieldName).toBe("orders");
+      expect(result.data).toHaveLength(2);
+      expect(result.data[0].id).toBe("u01");
+      expect(result.data[1].id).toBe("u02");
+      // User u01 (Alice) should have 2 orders
+      const aliceOrders = result.data[0].orders as Record<string, unknown>[];
+      expect(aliceOrders).toHaveLength(2);
+      expect(aliceOrders[0]).toEqual({ id: "o01", user: "u01", total: 100 });
+      expect(aliceOrders[1]).toEqual({ id: "o02", user: "u01", total: 50 });
+      // User u02 (Bob) should have 1 order
+      const bobOrders = result.data[1].orders as Record<string, unknown>[];
+      expect(bobOrders).toHaveLength(1);
+      expect(bobOrders[0].id).toBe("o03");
+    } finally {
+      fs.unlinkSync(orderCsvPath);
+    }
+  });
 });
 
 describe("parseCsv - reverse reference with resolveReferences: false", () => {

src/csv-loader/loader.ts

@@ -538,12 +538,13 @@ export interface ReverseReferenceDeclaration {
  */
 function parseReverseReferenceDeclaration(
   line: string,
+  commentChar: string = "#",
 ): ReverseReferenceDeclaration | null {
   const trimmed = line.trim();
-  // Must start with # (comment)
+  // Must start with the comment character
-  if (!trimmed.startsWith("#")) return null;
+  if (!trimmed.startsWith(commentChar)) return null;
 
-  const content = trimmed.slice(1).trim();
+  const content = trimmed.slice(commentChar.length).trim();
 
   // Match pattern: fieldName := ~tableName(foreignKey)
   const match = content.match(/^(\w+)\s*:=\s*~(\w+)\((\w+)\)(\?)?$/);
@@ -793,18 +794,36 @@ export function parseCsv(
     quote,
     escape,
     bom,
-    comment: undefined, // Don't let csv-parse skip comments; we need to parse them for reverse references
+    // Don't let csv-parse skip comments; we need to parse them for reverse references.
+    // Comment lines are filtered out manually below using the configured comment character.
+    comment: undefined,
     trim,
     skip_empty_lines: true,
     relax_column_count: true,
   });
 
-  if (records.length < 2) {
+  // Filter out comment lines from all records, collecting reverse reference declarations
+  const reverseReferences: ReverseReferenceDeclaration[] = [];
+  const filteredRecords: string[][] = [];
+  for (const row of records) {
+    const firstCell = (row[0] ?? "").trim();
+    if (comment && firstCell.startsWith(comment)) {
+      const decl = parseReverseReferenceDeclaration(firstCell, comment);
+      if (decl) {
+        reverseReferences.push(decl);
+      }
+      // Skip comment lines (whether or not they're reverse ref declarations)
+      continue;
+    }
+    filteredRecords.push(row);
+  }
+
+  if (filteredRecords.length < 2) {
     throw new Error("CSV must have at least 2 rows: headers and schemas");
   }
 
-  const headers = records[0];
+  const headers = filteredRecords[0];
-  const schemas = records[1];
+  const schemas = filteredRecords[1];
 
   if (headers.length !== schemas.length) {
     throw new Error(
@@ -812,30 +831,14 @@ export function parseCsv(
     );
   }
 
-  // Parse reverse reference declarations from comment lines between schema row and data rows
+  const dataRows = filteredRecords.slice(2);
-  const reverseReferences: ReverseReferenceDeclaration[] = [];
-  const dataRows: string[][] = [];
-  for (let i = 2; i < records.length; i++) {
-    const row = records[i];
-    // Check if this is a single-column row starting with # (comment with reverse ref declaration)
-    const firstCell = (row[0] ?? "").trim();
-    if (firstCell.startsWith("#")) {
-      const decl = parseReverseReferenceDeclaration(firstCell);
-      if (decl) {
-        reverseReferences.push(decl);
-      }
-      // Skip comment lines (whether or not they're reverse ref declarations)
-      continue;
-    }
-    dataRows.push(row);
-  }
 
   // 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++) {
     const cell = (schemas[col] ?? "").trim();
-    if (cell.startsWith("#")) {
+    if (comment && cell.startsWith(comment)) {
-      const decl = parseReverseReferenceDeclaration(cell);
+      const decl = parseReverseReferenceDeclaration(cell, comment);
       if (decl) {
         reverseReferences.push(decl);
       }