fix(query-builder): coerce table sort values to string to avoid localeCompare crash

The QueryTable column sorter called `.localeCompare` on values cast with
`as string`, which is compile-time only. Upstream `processTableRowValue`
normalizes numeric-looking strings to real numbers while null becomes the
string "N/A", so a grouped column can mix numbers and text. Comparing a
number cell against a text cell skipped the numeric branch and invoked
`(200).localeCompare(...)`, throwing "localeCompare is not a function" and
crashing the table on sort.

Extract the compare logic into `compareTableColumnValues` and coerce both
sides with `String(x ?? '')` so any value type sorts safely while
preserving empty-string semantics for null/undefined.

Affects all QueryTable surfaces: Traces/Logs table views, APM Top
Operations, and dashboard Table panels.

Fixes SIGNOZ-UI-5GC

frontend/src/lib/query/__tests__/createTableColumnsFromQuery.test.ts

@@ -0,0 +1,94 @@
+import {
+	compareTableColumnValues,
+	RowData,
+} from '../createTableColumnsFromQuery';
+
+// Builds a minimal RowData row. Values are intentionally loosely typed because
+// real query responses can put objects/arrays into cells despite RowData's
+// declared `string | number` index signature (that mismatch is the bug under test).
+const row = (value: unknown, dataIndex = 'col'): RowData =>
+	({
+		timestamp: 0,
+		key: 'k',
+		[dataIndex]: value,
+	}) as unknown as RowData;
+
+describe('compareTableColumnValues', () => {
+	it('sorts numerically when both cells are numbers', () => {
+		expect(compareTableColumnValues(row(1), row(2), 'col')).toBeLessThan(0);
+		expect(compareTableColumnValues(row(2), row(1), 'col')).toBeGreaterThan(0);
+		expect(compareTableColumnValues(row(5), row(5), 'col')).toBe(0);
+	});
+
+	it('sorts numeric-looking strings numerically, not lexically', () => {
+		// "10" vs "9": numeric branch => 10 - 9 > 0. A string compare would be < 0.
+		expect(compareTableColumnValues(row('10'), row('9'), 'col')).toBeGreaterThan(
+			0,
+		);
+	});
+
+	it('prefers the `<dataIndex>_without_unit` value for numeric comparison', () => {
+		const a = row('2 ms');
+		const b = row('10 ms');
+		a.col_without_unit = 2;
+		b.col_without_unit = 10;
+		expect(compareTableColumnValues(a, b, 'col')).toBeLessThan(0);
+	});
+
+	it('falls back to locale string compare for non-numeric strings', () => {
+		expect(compareTableColumnValues(row('abc'), row('abd'), 'col')).toBe(
+			'abc'.localeCompare('abd'),
+		);
+	});
+
+	it('treats null/undefined cells as empty string (no "null"/"undefined")', () => {
+		// Empty string sorts before a real word, and two empties are equal.
+		expect(compareTableColumnValues(row(null), row('a'), 'col')).toBeLessThan(0);
+		expect(compareTableColumnValues(row(undefined), row(undefined), 'col')).toBe(
+			0,
+		);
+		// If null coerced to the literal "null", this would sort after "a".
+		expect(
+			compareTableColumnValues(row(null), row('a'), 'col'),
+		).not.toBeGreaterThan(0);
+	});
+
+	it('does not throw when a cell value is an object', () => {
+		const a = row({ foo: 'bar' });
+		const b = row({ foo: 'baz' });
+		expect(() => compareTableColumnValues(a, b, 'col')).not.toThrow();
+		expect(typeof compareTableColumnValues(a, b, 'col')).toBe('number');
+	});
+
+	it('does not throw when a cell value is an array', () => {
+		const a = row([1, 2]);
+		const b = row([3, 4]);
+		expect(() => compareTableColumnValues(a, b, 'col')).not.toThrow();
+		// String([1,2]) === "1,2" < String([3,4]) === "3,4"
+		expect(compareTableColumnValues(a, b, 'col')).toBeLessThan(0);
+	});
+
+	it('does not throw when one cell is numeric and the other is an object', () => {
+		const a = row(42);
+		const b = row({ foo: 'bar' });
+		expect(() => compareTableColumnValues(a, b, 'col')).not.toThrow();
+		expect(typeof compareTableColumnValues(a, b, 'col')).toBe('number');
+	});
+
+	it('does not throw for a number cell compared against an "N/A" cell', () => {
+		// http.status_code column: [null, "200", ...] -> ["N/A", 200, ...]
+		const numberCell = row(200); // numeric string "200" becomes the number 200
+		const naCell = row('N/A'); // null becomes the string "N/A"
+
+		// Both orderings — antd's sorter compares pairs in both directions.
+		expect(() =>
+			compareTableColumnValues(numberCell, naCell, 'col'),
+		).not.toThrow();
+		expect(() =>
+			compareTableColumnValues(naCell, numberCell, 'col'),
+		).not.toThrow();
+		expect(typeof compareTableColumnValues(numberCell, naCell, 'col')).toBe(
+			'number',
+		);
+	});
+});

frontend/src/lib/query/createTableColumnsFromQuery.ts

@@ -637,6 +637,21 @@ const generateData = (
 	return data;
 };
 
+export const compareTableColumnValues = (
+	a: RowData,
+	b: RowData,
+	dataIndex: string,
+): number => {
+	const valueA = Number(a[`${dataIndex}_without_unit`] ?? a[dataIndex]);
+	const valueB = Number(b[`${dataIndex}_without_unit`] ?? b[dataIndex]);
+
+	if (!isNaN(valueA) && !isNaN(valueB)) {
+		return valueA - valueB;
+	}
+
+	return String(a[dataIndex] ?? '').localeCompare(String(b[dataIndex] ?? ''));
+};
+
 const generateTableColumns = (
 	dynamicColumns: DynamicColumns,
 	renderColumnCell?: QueryTableProps['renderColumnCell'],
@@ -650,18 +665,8 @@ const generateTableColumns = (
 			title: item.title,
 			width: QUERY_TABLE_CONFIG.width,
 			render: renderColumnCell && renderColumnCell[dataIndex],
-			sorter: (a: RowData, b: RowData): number => {
-				const valueA = Number(a[`${dataIndex}_without_unit`] ?? a[dataIndex]);
-				const valueB = Number(b[`${dataIndex}_without_unit`] ?? b[dataIndex]);
-
-				if (!isNaN(valueA) && !isNaN(valueB)) {
-					return valueA - valueB;
-				}
-
-				return ((a[dataIndex] as string) || '').localeCompare(
-					(b[dataIndex] as string) || '',
-				);
-			},
+			sorter: (a: RowData, b: RowData): number =>
+				compareTableColumnValues(a, b, dataIndex),
 		};
 
 		return [...acc, column];