Improve log parsing error messages

src/components/ErrorAlert.tsx

@@ -1,6 +1,7 @@
 import { Alert, AlertProps } from '@mantine/core';
 import { IconAlertCircle } from '@tabler/icons-react';
 import { ReactNode } from 'react';
+import { AlgorithmParseError } from '../utils/algorithm.tsx';
 
 export interface ErrorAlertProps extends Partial<AlertProps> {
   error: Error;
@@ -9,7 +10,7 @@ export interface ErrorAlertProps extends Partial<AlertProps> {
 export function ErrorAlert({ error, ...alertProps }: ErrorAlertProps): ReactNode {
   return (
     <Alert icon={<IconAlertCircle size={16} />} title="Error" color="red" {...alertProps}>
-      {error.message}
+      {error instanceof AlgorithmParseError ? error.node : error.message}
     </Alert>
   );
 }

src/pages/home/AlgorithmDetail.tsx

@@ -13,7 +13,7 @@ import {
   downloadAlgorithmResults,
   getAlgorithmLogsUrl,
   parseAlgorithmLogs,
-} from '../../utils/algorithm.ts';
+} from '../../utils/algorithm.tsx';
 import { formatNumber, formatTimestamp } from '../../utils/format.ts';
 
 export interface AlgorithmDetailProps {

src/pages/home/LoadFromFile.tsx

@@ -6,7 +6,7 @@ import { useNavigate } from 'react-router-dom';
 import { ErrorAlert } from '../../components/ErrorAlert.tsx';
 import { useAsync } from '../../hooks/use-async.ts';
 import { useStore } from '../../store.ts';
-import { parseAlgorithmLogs } from '../../utils/algorithm.ts';
+import { parseAlgorithmLogs } from '../../utils/algorithm.tsx';
 import { HomeCard } from './HomeCard.tsx';
 
 function DropzoneContent(): ReactNode {

src/pages/home/LoadFromUrl.tsx

@@ -5,7 +5,7 @@ import { useNavigate, useSearchParams } from 'react-router-dom';
 import { ErrorAlert } from '../../components/ErrorAlert.tsx';
 import { useAsync } from '../../hooks/use-async.ts';
 import { useStore } from '../../store.ts';
-import { parseAlgorithmLogs } from '../../utils/algorithm.ts';
+import { parseAlgorithmLogs } from '../../utils/algorithm.tsx';
 import { HomeCard } from './HomeCard.tsx';
 
 export function LoadFromUrl(): ReactNode {

src/pages/visualizer/AlgorithmSummaryCard.tsx

@@ -3,7 +3,7 @@ import { ReactNode } from 'react';
 import { ScrollableCodeHighlight } from '../../components/ScrollableCodeHighlight.tsx';
 import { useAsync } from '../../hooks/use-async.ts';
 import { useStore } from '../../store.ts';
-import { downloadAlgorithmLogs, downloadAlgorithmResults } from '../../utils/algorithm.ts';
+import { downloadAlgorithmLogs, downloadAlgorithmResults } from '../../utils/algorithm.tsx';
 import { formatTimestamp } from '../../utils/format.ts';
 import { VisualizerCard } from './VisualizerCard.tsx';
 

src/utils/algorithm.ts → src/utils/algorithm.tsx

@@ -1,3 +1,5 @@
+import { Code, Text } from '@mantine/core';
+import { ReactNode } from 'react';
 import {
   ActivityLogRow,
   Algorithm,
@@ -22,6 +24,12 @@ import {
 } from '../models.ts';
 import { authenticatedAxios } from './axios.ts';
 
+export class AlgorithmParseError extends Error {
+  public constructor(public readonly node: ReactNode) {
+    super('Failed to parse algorithm logs');
+  }
+}
+
 function getColumnValues(columns: string[], indices: number[]): number[] {
   const values: number[] = [];
 
@@ -219,7 +227,14 @@ function getAlgorithmData(logLines: string[]): AlgorithmDataRow[] {
     } catch (err) {
       console.log(line);
       console.error(err);
-      throw new Error('Sandbox logs are in invalid format, please see the prerequisites section above.');
+
+      throw new AlgorithmParseError(
+        /* prettier-ignore */
+        <>
+          <Text size="sm">Logs are in invalid format, please see the prerequisites section above. Could not parse the following line:</Text>
+          <Text size="sm">{line}</Text>
+        </>,
+      );
     }
   }
 
@@ -232,8 +247,17 @@ export function parseAlgorithmLogs(logs: string, summary?: AlgorithmSummary): Al
   const activityLogs = getActivityLogs(logLines);
   const data = getAlgorithmData(logLines);
 
+  if (activityLogs.length === 0 && data.length === 0) {
+    throw new AlgorithmParseError(
+      "Logs are empty, either something went wrong during with your submission or your backtester logs in a different format than Prosperity's submission environment.",
+    );
+  }
+
   if (activityLogs.length === 0 || data.length === 0) {
-    throw new Error('Logs are in invalid format, please see the prerequisites section above.');
+    throw new AlgorithmParseError(
+      /* prettier-ignore */
+      <Text size="sm">Logs are in invalid format, please see the prerequisites section above. You are likely missing a <Code>logger.flush()</Code> call at the end of <Code>Trader.run()</Code>.</Text>,
+    );
   }
 
   return {