From 4336a5d214c32a35161bd402525d2c75e349bc3f Mon Sep 17 00:00:00 2001
From: Hazelnoot <acomputerdog@gmail.com>
Date: Sun, 2 Nov 2025 10:29:23 -0500
Subject: [PATCH] extract QuantumKVCache custom errors to their own files to
 reduce the chance of future circular dependencies

---
 .../backend/src/core/CustomEmojiService.ts    |  2 +-
 packages/backend/src/misc/QuantumKVCache.ts   | 78 +------------------
 .../src/misc/errors/FetchFailedError.ts       | 30 +++++++
 .../src/misc/errors/KeyNotFoundError.ts       | 24 ++++++
 .../src/misc/errors/QuantumCacheError.ts      | 22 ++++++
 5 files changed, 80 insertions(+), 76 deletions(-)
 create mode 100644 packages/backend/src/misc/errors/FetchFailedError.ts
 create mode 100644 packages/backend/src/misc/errors/KeyNotFoundError.ts
 create mode 100644 packages/backend/src/misc/errors/QuantumCacheError.ts

diff --git a/packages/backend/src/core/CustomEmojiService.ts b/packages/backend/src/core/CustomEmojiService.ts
index 9c4b28e9e7..65bc4c6451 100644
--- a/packages/backend/src/core/CustomEmojiService.ts
+++ b/packages/backend/src/core/CustomEmojiService.ts
@@ -24,8 +24,8 @@ import { CacheManagementService, type ManagedQuantumKVCache } from '@/global/Cac
 import { TimeService } from '@/global/TimeService.js';
 import { LoggerService } from '@/core/LoggerService.js';
 import { isRetryableSymbol } from '@/misc/is-retryable-error.js';
-import { KeyNotFoundError } from '@/misc/QuantumKVCache.js';
 import type Logger from '@/logger.js';
+import { KeyNotFoundError } from '@/misc/errors/KeyNotFoundError.js';
 
 // TODO move to sk-types.d.ts when merged
 type MinEntity<T> = Omit<T, NullableProps<T>> & {
diff --git a/packages/backend/src/misc/QuantumKVCache.ts b/packages/backend/src/misc/QuantumKVCache.ts
index 23dcdc809b..3f74d4cd24 100644
--- a/packages/backend/src/misc/QuantumKVCache.ts
+++ b/packages/backend/src/misc/QuantumKVCache.ts
@@ -3,14 +3,15 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
+import { EntityNotFoundError } from 'typeorm';
 import { bindThis } from '@/decorators.js';
 import { InternalEventService } from '@/global/InternalEventService.js';
 import type { InternalEventTypes } from '@/core/GlobalEventService.js';
 import { MemoryKVCache, type MemoryCacheServices } from '@/misc/cache.js';
 import { makeKVPArray, type KVPArray } from '@/misc/kvp-array.js';
 import { renderInlineError } from '@/misc/render-inline-error.js';
-import { isRetryableSymbol } from '@/misc/is-retryable-error.js';
-import { EntityNotFoundError } from 'typeorm';
+import { FetchFailedError } from '@/misc/errors/FetchFailedError.js';
+import { KeyNotFoundError } from '@/misc/errors/KeyNotFoundError.js';
 
 export interface QuantumKVOpts<T> {
 	/**
@@ -469,76 +470,3 @@ export class QuantumKVCache<T> implements Iterable<readonly [key: string, value:
 	}
 }
 
-/**
- * Base class for all Quantum Cache errors.
- */
-export class QuantumCacheError extends Error {
-	/**
-	 * Name of the cache that produced this error.
-	 */
-	public readonly cacheName: string;
-
-	constructor(
-		cacheName: string,
-		message?: string,
-		options?: ErrorOptions,
-	) {
-		const actualMessage = message
-			? `Error in cache ${cacheName}: ${message}`
-			: `Error in cache ${cacheName}.`;
-		super(actualMessage, options);
-
-		this.cacheName = cacheName;
-	}
-}
-
-/**
- * Thrown when a fetch failed for any reason.
- */
-export class FetchFailedError extends QuantumCacheError {
-	/**
-	 * Name of the key(s) that could not be fetched.
-	 * Will be an array if bulkFetcher() failed, and a string if regular fetch() failed.
-	 */
-	public readonly keyNames: string | readonly string[];
-
-	constructor(
-		cacheName: string,
-		keyNames: string | readonly string[],
-		message?: string,
-		options?: ErrorOptions,
-	) {
-		const actualMessage = typeof(keyNames) === 'string'
-			? message
-				? `Fetch failed for key "${keyNames}": ${message}`
-				: `Fetch failed for key "${keyNames}".`
-			: message
-				? `Fetch failed for ${keyNames.length} keys: ${message}`
-				: `Fetch failed for ${keyNames.length} keys.`;
-		super(cacheName, actualMessage, options);
-
-		this.keyNames = keyNames;
-	}
-}
-
-/**
- * Thrown when a fetch failed because no value was found for the requested key(s).
- */
-export class KeyNotFoundError extends FetchFailedError {
-	/**
-	 * Missing keys are considered non-retryable, as they won't suddenly appear unless something external creates them.
-	 */
-	readonly [isRetryableSymbol] = false;
-
-	constructor(
-		cacheName: string,
-		keyNames: string | readonly string[],
-		message?: string,
-		options?: ErrorOptions,
-	) {
-		const actualMessage = message
-			? `Fetcher did not return a value: ${message}`
-			: 'Fetcher did not return a value.';
-		super(cacheName, keyNames, actualMessage, options);
-	}
-}
diff --git a/packages/backend/src/misc/errors/FetchFailedError.ts b/packages/backend/src/misc/errors/FetchFailedError.ts
new file mode 100644
index 0000000000..d5f8f74abc
--- /dev/null
+++ b/packages/backend/src/misc/errors/FetchFailedError.ts
@@ -0,0 +1,30 @@
+import { QuantumCacheError } from '@/misc/errors/QuantumCacheError.js';
+
+/**
+ * Thrown when a fetch failed for any reason.
+ */
+export class FetchFailedError extends QuantumCacheError {
+	/**
+	 * Name of the key(s) that could not be fetched.
+	 * Will be an array if bulkFetcher() failed, and a string if regular fetch() failed.
+	 */
+	public readonly keyNames: string | readonly string[];
+
+	constructor(
+		cacheName: string,
+		keyNames: string | readonly string[],
+		message?: string,
+		options?: ErrorOptions,
+	) {
+		const actualMessage = typeof (keyNames) === 'string'
+			? message
+				? `Fetch failed for key "${keyNames}": ${message}`
+				: `Fetch failed for key "${keyNames}".`
+			: message
+				? `Fetch failed for ${keyNames.length} keys: ${message}`
+				: `Fetch failed for ${keyNames.length} keys.`;
+		super(cacheName, actualMessage, options);
+
+		this.keyNames = keyNames;
+	}
+}
diff --git a/packages/backend/src/misc/errors/KeyNotFoundError.ts b/packages/backend/src/misc/errors/KeyNotFoundError.ts
new file mode 100644
index 0000000000..52b5a3ddf8
--- /dev/null
+++ b/packages/backend/src/misc/errors/KeyNotFoundError.ts
@@ -0,0 +1,24 @@
+import { FetchFailedError } from '@/misc/errors/FetchFailedError.js';
+import { isRetryableSymbol } from '@/misc/is-retryable-error.js';
+
+/**
+ * Thrown when a fetch failed because no value was found for the requested key(s).
+ */
+export class KeyNotFoundError extends FetchFailedError {
+	/**
+	 * Missing keys are considered non-retryable, as they won't suddenly appear unless something external creates them.
+	 */
+	readonly [isRetryableSymbol] = false;
+
+	constructor(
+		cacheName: string,
+		keyNames: string | readonly string[],
+		message?: string,
+		options?: ErrorOptions,
+	) {
+		const actualMessage = message
+			? `Fetcher did not return a value: ${message}`
+			: 'Fetcher did not return a value.';
+		super(cacheName, keyNames, actualMessage, options);
+	}
+}
diff --git a/packages/backend/src/misc/errors/QuantumCacheError.ts b/packages/backend/src/misc/errors/QuantumCacheError.ts
new file mode 100644
index 0000000000..d70331087d
--- /dev/null
+++ b/packages/backend/src/misc/errors/QuantumCacheError.ts
@@ -0,0 +1,22 @@
+/**
+ * Base class for all Quantum Cache errors.
+ */
+export class QuantumCacheError extends Error {
+	/**
+	 * Name of the cache that produced this error.
+	 */
+	public readonly cacheName: string;
+
+	constructor(
+		cacheName: string,
+		message?: string,
+		options?: ErrorOptions,
+	) {
+		const actualMessage = message
+			? `Error in cache ${cacheName}: ${message}`
+			: `Error in cache ${cacheName}.`;
+		super(actualMessage, options);
+
+		this.cacheName = cacheName;
+	}
+}