From 894944680f6e4852a56a6e36833896235310ad85 Mon Sep 17 00:00:00 2001
From: zkldi <20380519+zkldi@users.noreply.github.com>
Date: Wed, 24 Nov 2021 13:46:23 +0000
Subject: [PATCH] band-aid over partial-import failures in
 ImportAllIterableData.

---
 .../score-importing/score-import-main.ts      | 50 +++++++++++++++----
 1 file changed, 40 insertions(+), 10 deletions(-)

diff --git a/server/src/lib/score-import/framework/score-importing/score-import-main.ts b/server/src/lib/score-import/framework/score-importing/score-import-main.ts
index 572b0a52f..50513dc90 100644
--- a/server/src/lib/score-import/framework/score-importing/score-import-main.ts
+++ b/server/src/lib/score-import/framework/score-importing/score-import-main.ts
@@ -102,16 +102,46 @@ export default async function ScoreImportMain<D, C>(
 		// --- 2. Importing ---
 		// ImportAllIterableData iterates over the iterable, applying the converter function to each bit of data.
 		const importTimeStart = process.hrtime.bigint();
-		const importInfo = await ImportAllIterableData(
-			user.id,
-			importType,
-			iterable,
-			ConverterFunction,
-			context,
-			game,
-			logger,
-			job
-		);
+
+		let importInfo;
+		const startOfImportingScores = Date.now();
+
+		// Score imports are not transaction based. As such, if they fail midway through, corrupt state
+		// may occur. This sucks, but we can band-aid over some of the worse parts. Here, if our score
+		// import fails, we **know** that we might've inserted scores but not properly handled their
+		// state. If so, we should attempt to revert any of those scores.
+		//
+		// There are still places where Tachi can fail on importing scores and result in corrupt state,
+		// but this band-aid fix handles all known cases of a partial-import failure.
+		try {
+			importInfo = await ImportAllIterableData(
+				user.id,
+				importType,
+				iterable,
+				ConverterFunction,
+				context,
+				game,
+				logger,
+				job
+			);
+		} catch (err) {
+			logger.error(
+				`An error was thrown from ImportAllIterableData, which has resulted in a potential partial-score-import. Undoing scores inserted from this import.`,
+				{ err }
+			);
+
+			// Remove all scores from the database for this user which were imported after our timer started.
+			const r = await db.scores.remove({
+				userID: user.id,
+				timeAdded: { $gte: startOfImportingScores },
+			});
+
+			logger.error(
+				`Removed ${r.deletedCount} scores from the database to undo partial-import.`
+			);
+
+			throw err;
+		}
 
 		const importTime = GetMillisecondsSince(importTimeStart);
 		const importTimeRel = importTime / importInfo.length;