From d53b30c64e9bd40a939d8a286c8ef2f95e64b070 Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 11:48:11 +0100
Subject: [PATCH 01/12] WIP: Add makeIntegrationFn util

---
 packages/core/src/integration.ts           | 26 +++++++-
 packages/core/test/lib/integration.test.ts | 74 +++++++++++++++++++++-
 packages/types/src/index.ts                |  2 +-
 packages/types/src/integration.ts          | 44 ++++++++++++-
 4 files changed, 142 insertions(+), 4 deletions(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index 7be22a316e53..ca38adbd4513 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -1,4 +1,4 @@
-import type { Client, Event, EventHint, Integration, Options } from '@sentry/types';
+import type { Client, Event, EventHint, Integration, IntegrationFn, IntegrationFnResult, Options } from '@sentry/types';
 import { arrayify, logger } from '@sentry/utils';
 
 import { DEBUG_BUILD } from './debug-build';
@@ -155,3 +155,27 @@ function findIndex<T>(arr: T[], callback: (item: T) => boolean): number {
 
   return -1;
 }
+
+/**
+ * Generate a full integration function from a simple function.
+ * This will ensure to add the given name both to the function definition, as well as to the integration return value.
+ */
+export function makeIntegrationFn<
+  Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
+>(name: string, fn: Fn): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
+  const patchedFn = addIdToIntegrationFnResult(name, fn);
+
+
+  return Object.assign(patchedFn, { id: name });
+}
+
+function addIdToIntegrationFnResult<Fn extends (...rest: any[]) => Partial<IntegrationFnResult>>(
+  name: string,
+  fn: Fn,
+): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
+  const patchedFn = ((...rest: Parameters<Fn>): ReturnType<Fn> & { name: string } => {
+    return { ...fn(...rest), name } as ReturnType<Fn> & { name: string };
+  });
+
+  return patchedFn;
+}
diff --git a/packages/core/test/lib/integration.test.ts b/packages/core/test/lib/integration.test.ts
index 54bd426abb5c..9fd0c08040e8 100644
--- a/packages/core/test/lib/integration.test.ts
+++ b/packages/core/test/lib/integration.test.ts
@@ -2,7 +2,13 @@ import type { Integration, Options } from '@sentry/types';
 import { logger } from '@sentry/utils';
 
 import { Hub, makeMain } from '../../src/hub';
-import { addIntegration, getIntegrationsToSetup, installedIntegrations, setupIntegration } from '../../src/integration';
+import {
+  addIntegration,
+  getIntegrationsToSetup,
+  installedIntegrations,
+  makeIntegrationFn,
+  setupIntegration,
+} from '../../src/integration';
 import { TestClient, getDefaultTestClientOptions } from '../mocks/client';
 
 function getTestClient(): TestClient {
@@ -647,3 +653,69 @@ describe('addIntegration', () => {
     expect(warnings).toHaveBeenCalledWith('Cannot add integration "test" because no SDK Client is available.');
   });
 });
+
+describe('makeIntegrationFn', () => {
+  it('works with a minimal integration', () => {
+    const myIntegration = makeIntegrationFn('testName', () => {
+      return {};
+    });
+
+    expect(myIntegration.id).toBe('testName');
+
+    const integration = myIntegration();
+    expect(integration).toEqual({
+      name: 'testName',
+    });
+
+    // @ts-expect-error This SHOULD error
+    myIntegration({});
+  });
+
+  it('works with integration options', () => {
+    const myIntegration = makeIntegrationFn('testName', (_options: { xxx: string }) => {
+      return {};
+    });
+
+    expect(myIntegration.id).toBe('testName');
+
+    const integration = myIntegration({ xxx: 'aa' });
+    expect(integration).toEqual({
+      name: 'testName',
+    });
+
+    // @ts-expect-error This SHOULD error
+    myIntegration();
+    // @ts-expect-error This SHOULD error
+    myIntegration({});
+  });
+
+  it('works with integration hooks', () => {
+    const setup = jest.fn();
+    const setupOnce = jest.fn();
+    const processEvent = jest.fn();
+    const preprocessEvent = jest.fn();
+
+    const myIntegration = makeIntegrationFn('testName', () => {
+      return {
+        setup,
+        setupOnce,
+        processEvent,
+        preprocessEvent,
+      };
+    });
+
+    expect(myIntegration.id).toBe('testName');
+
+    const integration = myIntegration();
+    expect(integration).toEqual({
+      name: 'testName',
+      setup,
+      setupOnce,
+      processEvent,
+      preprocessEvent,
+    });
+
+    // @ts-expect-error This SHOULD error
+    makeIntegrationFn('testName', () => ({ other: 'aha' }));
+  });
+});
diff --git a/packages/types/src/index.ts b/packages/types/src/index.ts
index 7d3531599aa3..a2d75a193414 100644
--- a/packages/types/src/index.ts
+++ b/packages/types/src/index.ts
@@ -52,7 +52,7 @@ export type { EventProcessor } from './eventprocessor';
 export type { Exception } from './exception';
 export type { Extra, Extras } from './extra';
 export type { Hub } from './hub';
-export type { Integration, IntegrationClass } from './integration';
+export type { Integration, IntegrationClass, IntegrationFn, IntegrationFnResult } from './integration';
 export type { Mechanism } from './mechanism';
 export type { ExtractedNodeRequestData, HttpHeaderValue, Primitive, WorkerLocation } from './misc';
 export type { ClientOptions, Options } from './options';
diff --git a/packages/types/src/integration.ts b/packages/types/src/integration.ts
index 0c18845414e3..3e2f6e0dddec 100644
--- a/packages/types/src/integration.ts
+++ b/packages/types/src/integration.ts
@@ -10,7 +10,49 @@ export interface IntegrationClass<T> {
    */
   id: string;
 
-  new (...args: any[]): T;
+  new(...args: any[]): T;
+}
+
+/**
+ * An integration in function form.
+ * This is expected to return an integration result,
+ * and also have a `name` property that holds the integration name (so we can e.g. filter these before actually calling them).
+ */
+export type IntegrationFn<Fn extends ((...rest: any[]) => IntegrationFnResult)> = { id: string } & Fn;
+
+export interface IntegrationFnResult {
+  /**
+   * The name of the integration.
+   */
+  name: string;
+
+  /**
+   * This hook is only called once, even if multiple clients are created.
+   * It does not receives any arguments, and should only use for e.g. global monkey patching and similar things.
+   */
+  setupOnce?(): void;
+
+  /**
+   * Set up an integration for the given client.
+   * Receives the client as argument.
+   *
+   * Whenever possible, prefer this over `setupOnce`, as that is only run for the first client,
+   * whereas `setup` runs for each client. Only truly global things (e.g. registering global handlers)
+   * should be done in `setupOnce`.
+   */
+  setup?(client: Client): void;
+
+  /**
+   * An optional hook that allows to preprocess an event _before_ it is passed to all other event processors.
+   */
+  preprocessEvent?(event: Event, hint: EventHint | undefined, client: Client): void;
+
+  /**
+   * An optional hook that allows to process an event.
+   * Return `null` to drop the event, or mutate the event & return it.
+   * This receives the client that the integration was installed for as third argument.
+   */
+  processEvent?(event: Event, hint: EventHint, client: Client): Event | null | PromiseLike<Event | null>;
 }
 
 /** Integration interface */

From ed7652c03a5b65a5f3d545232c497a6496e10c76 Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 13:34:57 +0100
Subject: [PATCH 02/12] WIP: add convertIntegrationFnToClass util

---
 packages/core/src/integration.ts           | 45 +++++++++++++++++----
 packages/core/test/lib/integration.test.ts | 46 ++++++++++++++++++++++
 2 files changed, 84 insertions(+), 7 deletions(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index ca38adbd4513..d4fe3c2d8968 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -1,4 +1,13 @@
-import type { Client, Event, EventHint, Integration, IntegrationFn, IntegrationFnResult, Options } from '@sentry/types';
+import type {
+  Client,
+  Event,
+  EventHint,
+  Integration,
+  IntegrationClass,
+  IntegrationFn,
+  IntegrationFnResult,
+  Options,
+} from '@sentry/types';
 import { arrayify, logger } from '@sentry/utils';
 
 import { DEBUG_BUILD } from './debug-build';
@@ -160,22 +169,44 @@ function findIndex<T>(arr: T[], callback: (item: T) => boolean): number {
  * Generate a full integration function from a simple function.
  * This will ensure to add the given name both to the function definition, as well as to the integration return value.
  */
-export function makeIntegrationFn<
-  Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
->(name: string, fn: Fn): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
+export function makeIntegrationFn<Fn extends (...rest: any[]) => Partial<IntegrationFnResult>>(
+  name: string,
+  fn: Fn,
+): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
   const patchedFn = addIdToIntegrationFnResult(name, fn);
 
-
   return Object.assign(patchedFn, { id: name });
 }
 
+/**
+ * Convert a new integration function to the legacy class syntax.
+ * In v8, we can remove this and instead export the integration functions directly.
+ */
+export function convertIntegrationFnToClass<Fn extends IntegrationFn<(...rest: any[]) => IntegrationFnResult>>(
+  fn: Fn,
+): IntegrationClass<Integration> {
+  return Object.assign(
+    function ConvertedIntegration(...rest: any[]) {
+      const res = {
+        // eslint-disable-next-line @typescript-eslint/no-empty-function
+        setupOnce: () => {},
+        ...fn(...rest),
+        name: fn.id,
+      };
+
+      return res;
+    },
+    { id: fn.id },
+  ) as unknown as IntegrationClass<Integration>;
+}
+
 function addIdToIntegrationFnResult<Fn extends (...rest: any[]) => Partial<IntegrationFnResult>>(
   name: string,
   fn: Fn,
 ): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
-  const patchedFn = ((...rest: Parameters<Fn>): ReturnType<Fn> & { name: string } => {
+  const patchedFn = (...rest: Parameters<Fn>): ReturnType<Fn> & { name: string } => {
     return { ...fn(...rest), name } as ReturnType<Fn> & { name: string };
-  });
+  };
 
   return patchedFn;
 }
diff --git a/packages/core/test/lib/integration.test.ts b/packages/core/test/lib/integration.test.ts
index 9fd0c08040e8..97bf21de4a35 100644
--- a/packages/core/test/lib/integration.test.ts
+++ b/packages/core/test/lib/integration.test.ts
@@ -4,6 +4,7 @@ import { logger } from '@sentry/utils';
 import { Hub, makeMain } from '../../src/hub';
 import {
   addIntegration,
+  convertIntegrationFnToClass,
   getIntegrationsToSetup,
   installedIntegrations,
   makeIntegrationFn,
@@ -719,3 +720,48 @@ describe('makeIntegrationFn', () => {
     makeIntegrationFn('testName', () => ({ other: 'aha' }));
   });
 });
+
+describe('convertIntegrationFnToClass', () => {
+  it('works with a minimal integration', () => {
+    const integrationFn = makeIntegrationFn('testName', () => ({}));
+
+    const IntegrationClass = convertIntegrationFnToClass(integrationFn);
+
+    expect(IntegrationClass.id).toBe('testName');
+
+    const integration = new IntegrationClass();
+    expect(integration).toEqual({
+      name: 'testName',
+      setupOnce: expect.any(Function),
+    });
+  });
+
+  it('works with integration hooks', () => {
+    const setup = jest.fn();
+    const setupOnce = jest.fn();
+    const processEvent = jest.fn();
+    const preprocessEvent = jest.fn();
+
+    const integrationFn = makeIntegrationFn('testName', () => {
+      return {
+        setup,
+        setupOnce,
+        processEvent,
+        preprocessEvent,
+      };
+    });
+
+    const IntegrationClass = convertIntegrationFnToClass(integrationFn);
+
+    expect(IntegrationClass.id).toBe('testName');
+
+    const integration = new IntegrationClass();
+    expect(integration).toEqual({
+      name: 'testName',
+      setupOnce,
+      setup,
+      processEvent,
+      preprocessEvent,
+    });
+  });
+});

From a91624aab6b40b8730fee3f3793e3b442aa6a1f7 Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 13:37:32 +0100
Subject: [PATCH 03/12] export it

---
 packages/core/src/index.ts                 |  8 ++++++-
 packages/core/src/integration.ts           | 26 +++++++++++++---------
 packages/core/test/lib/integration.test.ts |  2 ++
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index ccf219031b8f..88ad4299e377 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -54,7 +54,13 @@ export { createTransport } from './transports/base';
 export { makeOfflineTransport } from './transports/offline';
 export { makeMultiplexedTransport } from './transports/multiplexed';
 export { SDK_VERSION } from './version';
-export { getIntegrationsToSetup, addIntegration } from './integration';
+export {
+  getIntegrationsToSetup,
+  addIntegration,
+  // eslint-disable-next-line deprecation/deprecation
+  convertIntegrationFnToClass,
+  makeIntegrationFn,
+} from './integration';
 export { FunctionToString, InboundFilters, LinkedErrors } from './integrations';
 export { prepareEvent } from './utils/prepareEvent';
 export { createCheckInEnvelope } from './checkin';
diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index d4fe3c2d8968..68cca759f053 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -169,10 +169,10 @@ function findIndex<T>(arr: T[], callback: (item: T) => boolean): number {
  * Generate a full integration function from a simple function.
  * This will ensure to add the given name both to the function definition, as well as to the integration return value.
  */
-export function makeIntegrationFn<Fn extends (...rest: any[]) => Partial<IntegrationFnResult>>(
-  name: string,
-  fn: Fn,
-): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
+export function makeIntegrationFn<
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
+>(name: string, fn: Fn): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
   const patchedFn = addIdToIntegrationFnResult(name, fn);
 
   return Object.assign(patchedFn, { id: name });
@@ -181,11 +181,15 @@ export function makeIntegrationFn<Fn extends (...rest: any[]) => Partial<Integra
 /**
  * Convert a new integration function to the legacy class syntax.
  * In v8, we can remove this and instead export the integration functions directly.
+ *
+ * @deprecated This will be removed in v8!
  */
-export function convertIntegrationFnToClass<Fn extends IntegrationFn<(...rest: any[]) => IntegrationFnResult>>(
-  fn: Fn,
-): IntegrationClass<Integration> {
+export function convertIntegrationFnToClass<
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  Fn extends IntegrationFn<(...rest: any[]) => IntegrationFnResult>,
+>(fn: Fn): IntegrationClass<Integration> {
   return Object.assign(
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     function ConvertedIntegration(...rest: any[]) {
       const res = {
         // eslint-disable-next-line @typescript-eslint/no-empty-function
@@ -200,10 +204,10 @@ export function convertIntegrationFnToClass<Fn extends IntegrationFn<(...rest: a
   ) as unknown as IntegrationClass<Integration>;
 }
 
-function addIdToIntegrationFnResult<Fn extends (...rest: any[]) => Partial<IntegrationFnResult>>(
-  name: string,
-  fn: Fn,
-): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
+function addIdToIntegrationFnResult<
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
+>(name: string, fn: Fn): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
   const patchedFn = (...rest: Parameters<Fn>): ReturnType<Fn> & { name: string } => {
     return { ...fn(...rest), name } as ReturnType<Fn> & { name: string };
   };
diff --git a/packages/core/test/lib/integration.test.ts b/packages/core/test/lib/integration.test.ts
index 97bf21de4a35..0907fb210e8f 100644
--- a/packages/core/test/lib/integration.test.ts
+++ b/packages/core/test/lib/integration.test.ts
@@ -722,6 +722,7 @@ describe('makeIntegrationFn', () => {
 });
 
 describe('convertIntegrationFnToClass', () => {
+  /* eslint-disable deprecation/deprecation */
   it('works with a minimal integration', () => {
     const integrationFn = makeIntegrationFn('testName', () => ({}));
 
@@ -764,4 +765,5 @@ describe('convertIntegrationFnToClass', () => {
       preprocessEvent,
     });
   });
+  /* eslint-enable deprecation/deprecation */
 });

From a12c4059cc27b43694a18fcc8e8da0add54e009a Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 13:42:28 +0100
Subject: [PATCH 04/12] refactor one integration as an example

---
 .../core/src/integrations/inboundfilters.ts   | 49 ++++++-------------
 1 file changed, 14 insertions(+), 35 deletions(-)

diff --git a/packages/core/src/integrations/inboundfilters.ts b/packages/core/src/integrations/inboundfilters.ts
index 9d348a4b4d23..054679ba5ada 100644
--- a/packages/core/src/integrations/inboundfilters.ts
+++ b/packages/core/src/integrations/inboundfilters.ts
@@ -2,6 +2,7 @@ import type { Client, Event, EventHint, Integration, StackFrame } from '@sentry/
 import { getEventDescription, logger, stringMatchesSomePattern } from '@sentry/utils';
 
 import { DEBUG_BUILD } from '../debug-build';
+import { convertIntegrationFnToClass, makeIntegrationFn } from '../integration';
 
 // "Script error." is hard coded into browsers for errors that it can't read.
 // this is the result of a script being pulled in from an external domain and CORS.
@@ -28,42 +29,21 @@ export interface InboundFiltersOptions {
   disableTransactionDefaults: boolean;
 }
 
-/** Inbound filters configurable by the user */
-export class InboundFilters implements Integration {
-  /**
-   * @inheritDoc
-   */
-  public static id: string = 'InboundFilters';
-
-  /**
-   * @inheritDoc
-   */
-  public name: string;
-
-  private readonly _options: Partial<InboundFiltersOptions>;
-
-  public constructor(options: Partial<InboundFiltersOptions> = {}) {
-    this.name = InboundFilters.id;
-    this._options = options;
-  }
-
-  /**
-   * @inheritDoc
-   */
-  public setupOnce(_addGlobalEventProcessor: unknown, _getCurrentHub: unknown): void {
-    // noop
+const inboundFiltersIntegration = makeIntegrationFn('InboundFilters', (options: Partial<InboundFiltersOptions>) => {
+  return {
+    processEvent(event, _hint, client) {
+      const clientOptions = client.getOptions();
+      const mergedOptions = _mergeOptions(options, clientOptions);
+      return _shouldDropEvent(event, mergedOptions) ? null : event;
+    }
   }
+});
 
-  /** @inheritDoc */
-  public processEvent(event: Event, _eventHint: EventHint, client: Client): Event | null {
-    const clientOptions = client.getOptions();
-    const options = _mergeOptions(this._options, clientOptions);
-    return _shouldDropEvent(event, options) ? null : event;
-  }
-}
+/** Inbound filters configurable by the user */
+// eslint-disable-next-line deprecation/deprecation
+export const InboundFilters = convertIntegrationFnToClass(inboundFiltersIntegration);
 
-/** JSDoc */
-export function _mergeOptions(
+function _mergeOptions(
   internalOptions: Partial<InboundFiltersOptions> = {},
   clientOptions: Partial<InboundFiltersOptions> = {},
 ): Partial<InboundFiltersOptions> {
@@ -84,8 +64,7 @@ export function _mergeOptions(
   };
 }
 
-/** JSDoc */
-export function _shouldDropEvent(event: Event, options: Partial<InboundFiltersOptions>): boolean {
+function _shouldDropEvent(event: Event, options: Partial<InboundFiltersOptions>): boolean {
   if (options.ignoreInternal && _isSentryError(event)) {
     DEBUG_BUILD &&
       logger.warn(`Event dropped due to being internal Sentry Error.\nEvent: ${getEventDescription(event)}`);

From 67e2daac74f45d1b4cf4cc291422b4e33ec43ee4 Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 13:50:16 +0100
Subject: [PATCH 05/12] small doc

---
 packages/core/src/integration.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index 68cca759f053..df37530abe20 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -167,7 +167,8 @@ function findIndex<T>(arr: T[], callback: (item: T) => boolean): number {
 
 /**
  * Generate a full integration function from a simple function.
- * This will ensure to add the given name both to the function definition, as well as to the integration return value.
+ * This will ensure to add the given name both to the function definition (as id),
+ * as well as to the integration return value.
  */
 export function makeIntegrationFn<
   // eslint-disable-next-line @typescript-eslint/no-explicit-any

From 57ed4d22dc533c8fe9e90554985f24735d9151aa Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 14:06:02 +0100
Subject: [PATCH 06/12] fix linting

---
 packages/core/src/integration.ts                 | 4 ++--
 packages/core/src/integrations/inboundfilters.ts | 4 ++--
 packages/types/src/integration.ts                | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index df37530abe20..23dcb4eca9f5 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -174,7 +174,7 @@ export function makeIntegrationFn<
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
 >(name: string, fn: Fn): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
-  const patchedFn = addIdToIntegrationFnResult(name, fn);
+  const patchedFn = addNameToIntegrationFnResult(name, fn);
 
   return Object.assign(patchedFn, { id: name });
 }
@@ -205,7 +205,7 @@ export function convertIntegrationFnToClass<
   ) as unknown as IntegrationClass<Integration>;
 }
 
-function addIdToIntegrationFnResult<
+function addNameToIntegrationFnResult<
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
 >(name: string, fn: Fn): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
diff --git a/packages/core/src/integrations/inboundfilters.ts b/packages/core/src/integrations/inboundfilters.ts
index 054679ba5ada..309315577296 100644
--- a/packages/core/src/integrations/inboundfilters.ts
+++ b/packages/core/src/integrations/inboundfilters.ts
@@ -35,8 +35,8 @@ const inboundFiltersIntegration = makeIntegrationFn('InboundFilters', (options:
       const clientOptions = client.getOptions();
       const mergedOptions = _mergeOptions(options, clientOptions);
       return _shouldDropEvent(event, mergedOptions) ? null : event;
-    }
-  }
+    },
+  };
 });
 
 /** Inbound filters configurable by the user */
diff --git a/packages/types/src/integration.ts b/packages/types/src/integration.ts
index 3e2f6e0dddec..7f8816859010 100644
--- a/packages/types/src/integration.ts
+++ b/packages/types/src/integration.ts
@@ -10,7 +10,7 @@ export interface IntegrationClass<T> {
    */
   id: string;
 
-  new(...args: any[]): T;
+  new (...args: any[]): T;
 }
 
 /**
@@ -18,7 +18,7 @@ export interface IntegrationClass<T> {
  * This is expected to return an integration result,
  * and also have a `name` property that holds the integration name (so we can e.g. filter these before actually calling them).
  */
-export type IntegrationFn<Fn extends ((...rest: any[]) => IntegrationFnResult)> = { id: string } & Fn;
+export type IntegrationFn<Fn extends (...rest: any[]) => IntegrationFnResult> = { id: string } & Fn;
 
 export interface IntegrationFnResult {
   /**

From b1a536d0516727983fae98f24959d4cbfcaf323f Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 14:57:26 +0100
Subject: [PATCH 07/12] PR feedback

---
 packages/core/src/integration.ts | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index 23dcb4eca9f5..3f3480cab2fd 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -174,9 +174,12 @@ export function makeIntegrationFn<
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
 >(name: string, fn: Fn): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
-  const patchedFn = addNameToIntegrationFnResult(name, fn);
+  const patchedFn = addNameToIntegrationFnResult(name, fn) as ((
+    ...rest: Parameters<Fn>
+  ) => ReturnType<Fn> & { name: string }) & { id: string };
 
-  return Object.assign(patchedFn, { id: name });
+  patchedFn.id = name;
+  return patchedFn;
 }
 
 /**
@@ -192,14 +195,12 @@ export function convertIntegrationFnToClass<
   return Object.assign(
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     function ConvertedIntegration(...rest: any[]) {
-      const res = {
+      return {
         // eslint-disable-next-line @typescript-eslint/no-empty-function
         setupOnce: () => {},
         ...fn(...rest),
         name: fn.id,
       };
-
-      return res;
     },
     { id: fn.id },
   ) as unknown as IntegrationClass<Integration>;
@@ -210,7 +211,9 @@ function addNameToIntegrationFnResult<
   Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
 >(name: string, fn: Fn): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
   const patchedFn = (...rest: Parameters<Fn>): ReturnType<Fn> & { name: string } => {
-    return { ...fn(...rest), name } as ReturnType<Fn> & { name: string };
+    const result = fn(...rest);
+    result.name = name;
+    return result as ReturnType<Fn> & { name: string };
   };
 
   return patchedFn;

From a053678fdb4250d1369fe93a4ead9af23b2b47ac Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Wed, 13 Dec 2023 15:07:08 +0100
Subject: [PATCH 08/12] try make it preprocess??

---
 packages/integrations/src/contextlines.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/integrations/src/contextlines.ts b/packages/integrations/src/contextlines.ts
index d716ca2fbb5f..7812cea358fb 100644
--- a/packages/integrations/src/contextlines.ts
+++ b/packages/integrations/src/contextlines.ts
@@ -49,8 +49,8 @@ export class ContextLines implements Integration {
   }
 
   /** @inheritDoc */
-  public processEvent(event: Event): Event {
-    return this.addSourceContext(event);
+  public preprocessEvent(event: Event): void {
+    this.addSourceContext(event);
   }
 
   /**

From 8771e998c82469efd240aad312b2b0cd12ff623f Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Thu, 14 Dec 2023 14:54:26 +0100
Subject: [PATCH 09/12] Revert "try make it preprocess??"

This reverts commit 31887622b297c094e37ccfa00b2a8708bd0d73c7.
---
 packages/integrations/src/contextlines.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/integrations/src/contextlines.ts b/packages/integrations/src/contextlines.ts
index 7812cea358fb..d716ca2fbb5f 100644
--- a/packages/integrations/src/contextlines.ts
+++ b/packages/integrations/src/contextlines.ts
@@ -49,8 +49,8 @@ export class ContextLines implements Integration {
   }
 
   /** @inheritDoc */
-  public preprocessEvent(event: Event): void {
-    this.addSourceContext(event);
+  public processEvent(event: Event): Event {
+    return this.addSourceContext(event);
   }
 
   /**

From c5c8d82e51df816b482838bb3c8b5571654df2de Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Thu, 14 Dec 2023 15:13:31 +0100
Subject: [PATCH 10/12] reduce

---
 packages/core/src/integration.ts              | 36 ++++---------------
 .../core/src/integrations/inboundfilters.ts   |  6 ++--
 packages/core/test/lib/integration.test.ts    | 30 ++++++++--------
 packages/types/src/integration.ts             |  3 +-
 4 files changed, 27 insertions(+), 48 deletions(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index 3f3480cab2fd..e2d265509754 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -170,16 +170,8 @@ function findIndex<T>(arr: T[], callback: (item: T) => boolean): number {
  * This will ensure to add the given name both to the function definition (as id),
  * as well as to the integration return value.
  */
-export function makeIntegrationFn<
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
->(name: string, fn: Fn): ((...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string }) & { id: string } {
-  const patchedFn = addNameToIntegrationFnResult(name, fn) as ((
-    ...rest: Parameters<Fn>
-  ) => ReturnType<Fn> & { name: string }) & { id: string };
-
-  patchedFn.id = name;
-  return patchedFn;
+export function makeIntegrationFn<Fn extends IntegrationFn>(fn: Fn): Fn {
+  return fn;
 }
 
 /**
@@ -188,10 +180,10 @@ export function makeIntegrationFn<
  *
  * @deprecated This will be removed in v8!
  */
-export function convertIntegrationFnToClass<
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  Fn extends IntegrationFn<(...rest: any[]) => IntegrationFnResult>,
->(fn: Fn): IntegrationClass<Integration> {
+export function convertIntegrationFnToClass<Fn extends IntegrationFn>(
+  name: string,
+  fn: Fn,
+): IntegrationClass<Integration> {
   return Object.assign(
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     function ConvertedIntegration(...rest: any[]) {
@@ -199,22 +191,8 @@ export function convertIntegrationFnToClass<
         // eslint-disable-next-line @typescript-eslint/no-empty-function
         setupOnce: () => {},
         ...fn(...rest),
-        name: fn.id,
       };
     },
-    { id: fn.id },
+    { id: name },
   ) as unknown as IntegrationClass<Integration>;
 }
-
-function addNameToIntegrationFnResult<
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  Fn extends (...rest: any[]) => Partial<IntegrationFnResult>,
->(name: string, fn: Fn): (...rest: Parameters<Fn>) => ReturnType<Fn> & { name: string } {
-  const patchedFn = (...rest: Parameters<Fn>): ReturnType<Fn> & { name: string } => {
-    const result = fn(...rest);
-    result.name = name;
-    return result as ReturnType<Fn> & { name: string };
-  };
-
-  return patchedFn;
-}
diff --git a/packages/core/src/integrations/inboundfilters.ts b/packages/core/src/integrations/inboundfilters.ts
index 309315577296..af9bffbf9c8f 100644
--- a/packages/core/src/integrations/inboundfilters.ts
+++ b/packages/core/src/integrations/inboundfilters.ts
@@ -29,8 +29,10 @@ export interface InboundFiltersOptions {
   disableTransactionDefaults: boolean;
 }
 
-const inboundFiltersIntegration = makeIntegrationFn('InboundFilters', (options: Partial<InboundFiltersOptions>) => {
+const INTEGRATION_NAME = 'InboundFilters';
+const inboundFiltersIntegration = makeIntegrationFn((options: Partial<InboundFiltersOptions>) => {
   return {
+    name: INTEGRATION_NAME,
     processEvent(event, _hint, client) {
       const clientOptions = client.getOptions();
       const mergedOptions = _mergeOptions(options, clientOptions);
@@ -41,7 +43,7 @@ const inboundFiltersIntegration = makeIntegrationFn('InboundFilters', (options:
 
 /** Inbound filters configurable by the user */
 // eslint-disable-next-line deprecation/deprecation
-export const InboundFilters = convertIntegrationFnToClass(inboundFiltersIntegration);
+export const InboundFilters = convertIntegrationFnToClass(INTEGRATION_NAME, inboundFiltersIntegration);
 
 function _mergeOptions(
   internalOptions: Partial<InboundFiltersOptions> = {},
diff --git a/packages/core/test/lib/integration.test.ts b/packages/core/test/lib/integration.test.ts
index 0907fb210e8f..00efc3a7b1a0 100644
--- a/packages/core/test/lib/integration.test.ts
+++ b/packages/core/test/lib/integration.test.ts
@@ -657,12 +657,12 @@ describe('addIntegration', () => {
 
 describe('makeIntegrationFn', () => {
   it('works with a minimal integration', () => {
-    const myIntegration = makeIntegrationFn('testName', () => {
-      return {};
+    const myIntegration = makeIntegrationFn(() => {
+      return {
+        name: 'testName'
+      };
     });
 
-    expect(myIntegration.id).toBe('testName');
-
     const integration = myIntegration();
     expect(integration).toEqual({
       name: 'testName',
@@ -673,12 +673,12 @@ describe('makeIntegrationFn', () => {
   });
 
   it('works with integration options', () => {
-    const myIntegration = makeIntegrationFn('testName', (_options: { xxx: string }) => {
-      return {};
+    const myIntegration = makeIntegrationFn((_options: { xxx: string }) => {
+      return {
+        name: 'testName'
+      };
     });
 
-    expect(myIntegration.id).toBe('testName');
-
     const integration = myIntegration({ xxx: 'aa' });
     expect(integration).toEqual({
       name: 'testName',
@@ -696,8 +696,9 @@ describe('makeIntegrationFn', () => {
     const processEvent = jest.fn();
     const preprocessEvent = jest.fn();
 
-    const myIntegration = makeIntegrationFn('testName', () => {
+    const myIntegration = makeIntegrationFn(() => {
       return {
+        name: 'testName',
         setup,
         setupOnce,
         processEvent,
@@ -705,8 +706,6 @@ describe('makeIntegrationFn', () => {
       };
     });
 
-    expect(myIntegration.id).toBe('testName');
-
     const integration = myIntegration();
     expect(integration).toEqual({
       name: 'testName',
@@ -724,9 +723,9 @@ describe('makeIntegrationFn', () => {
 describe('convertIntegrationFnToClass', () => {
   /* eslint-disable deprecation/deprecation */
   it('works with a minimal integration', () => {
-    const integrationFn = makeIntegrationFn('testName', () => ({}));
+    const integrationFn = makeIntegrationFn(() => ({ name: 'testName'}));
 
-    const IntegrationClass = convertIntegrationFnToClass(integrationFn);
+    const IntegrationClass = convertIntegrationFnToClass('testName', integrationFn);
 
     expect(IntegrationClass.id).toBe('testName');
 
@@ -743,8 +742,9 @@ describe('convertIntegrationFnToClass', () => {
     const processEvent = jest.fn();
     const preprocessEvent = jest.fn();
 
-    const integrationFn = makeIntegrationFn('testName', () => {
+    const integrationFn = makeIntegrationFn( () => {
       return {
+        name: 'testName',
         setup,
         setupOnce,
         processEvent,
@@ -752,7 +752,7 @@ describe('convertIntegrationFnToClass', () => {
       };
     });
 
-    const IntegrationClass = convertIntegrationFnToClass(integrationFn);
+    const IntegrationClass = convertIntegrationFnToClass('testName', integrationFn);
 
     expect(IntegrationClass.id).toBe('testName');
 
diff --git a/packages/types/src/integration.ts b/packages/types/src/integration.ts
index 7f8816859010..a4108a60c749 100644
--- a/packages/types/src/integration.ts
+++ b/packages/types/src/integration.ts
@@ -16,9 +16,8 @@ export interface IntegrationClass<T> {
 /**
  * An integration in function form.
  * This is expected to return an integration result,
- * and also have a `name` property that holds the integration name (so we can e.g. filter these before actually calling them).
  */
-export type IntegrationFn<Fn extends (...rest: any[]) => IntegrationFnResult> = { id: string } & Fn;
+export type IntegrationFn = (...rest: any[]) => IntegrationFnResult;
 
 export interface IntegrationFnResult {
   /**

From 87446e955ceb5a487fcaaf4c4f10910065fc0bc8 Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Fri, 15 Dec 2023 12:21:06 +0100
Subject: [PATCH 11/12] avoid unncessary function

---
 packages/core/src/index.ts                    |  1 -
 packages/core/src/integration.ts              | 10 ---
 .../core/src/integrations/inboundfilters.ts   |  8 +--
 packages/core/test/lib/integration.test.ts    | 70 +------------------
 4 files changed, 7 insertions(+), 82 deletions(-)

diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 88ad4299e377..3c39921f495a 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -59,7 +59,6 @@ export {
   addIntegration,
   // eslint-disable-next-line deprecation/deprecation
   convertIntegrationFnToClass,
-  makeIntegrationFn,
 } from './integration';
 export { FunctionToString, InboundFilters, LinkedErrors } from './integrations';
 export { prepareEvent } from './utils/prepareEvent';
diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index e2d265509754..9316039e4917 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -5,7 +5,6 @@ import type {
   Integration,
   IntegrationClass,
   IntegrationFn,
-  IntegrationFnResult,
   Options,
 } from '@sentry/types';
 import { arrayify, logger } from '@sentry/utils';
@@ -165,15 +164,6 @@ function findIndex<T>(arr: T[], callback: (item: T) => boolean): number {
   return -1;
 }
 
-/**
- * Generate a full integration function from a simple function.
- * This will ensure to add the given name both to the function definition (as id),
- * as well as to the integration return value.
- */
-export function makeIntegrationFn<Fn extends IntegrationFn>(fn: Fn): Fn {
-  return fn;
-}
-
 /**
  * Convert a new integration function to the legacy class syntax.
  * In v8, we can remove this and instead export the integration functions directly.
diff --git a/packages/core/src/integrations/inboundfilters.ts b/packages/core/src/integrations/inboundfilters.ts
index af9bffbf9c8f..df560175ad78 100644
--- a/packages/core/src/integrations/inboundfilters.ts
+++ b/packages/core/src/integrations/inboundfilters.ts
@@ -1,8 +1,8 @@
-import type { Client, Event, EventHint, Integration, StackFrame } from '@sentry/types';
+import type {  Event, IntegrationFn, StackFrame } from '@sentry/types';
 import { getEventDescription, logger, stringMatchesSomePattern } from '@sentry/utils';
 
 import { DEBUG_BUILD } from '../debug-build';
-import { convertIntegrationFnToClass, makeIntegrationFn } from '../integration';
+import { convertIntegrationFnToClass } from '../integration';
 
 // "Script error." is hard coded into browsers for errors that it can't read.
 // this is the result of a script being pulled in from an external domain and CORS.
@@ -30,7 +30,7 @@ export interface InboundFiltersOptions {
 }
 
 const INTEGRATION_NAME = 'InboundFilters';
-const inboundFiltersIntegration = makeIntegrationFn((options: Partial<InboundFiltersOptions>) => {
+const inboundFiltersIntegration: IntegrationFn = (options: Partial<InboundFiltersOptions>) => {
   return {
     name: INTEGRATION_NAME,
     processEvent(event, _hint, client) {
@@ -39,7 +39,7 @@ const inboundFiltersIntegration = makeIntegrationFn((options: Partial<InboundFil
       return _shouldDropEvent(event, mergedOptions) ? null : event;
     },
   };
-});
+}
 
 /** Inbound filters configurable by the user */
 // eslint-disable-next-line deprecation/deprecation
diff --git a/packages/core/test/lib/integration.test.ts b/packages/core/test/lib/integration.test.ts
index 00efc3a7b1a0..9c767189964e 100644
--- a/packages/core/test/lib/integration.test.ts
+++ b/packages/core/test/lib/integration.test.ts
@@ -7,7 +7,6 @@ import {
   convertIntegrationFnToClass,
   getIntegrationsToSetup,
   installedIntegrations,
-  makeIntegrationFn,
   setupIntegration,
 } from '../../src/integration';
 import { TestClient, getDefaultTestClientOptions } from '../mocks/client';
@@ -655,75 +654,12 @@ describe('addIntegration', () => {
   });
 });
 
-describe('makeIntegrationFn', () => {
-  it('works with a minimal integration', () => {
-    const myIntegration = makeIntegrationFn(() => {
-      return {
-        name: 'testName'
-      };
-    });
-
-    const integration = myIntegration();
-    expect(integration).toEqual({
-      name: 'testName',
-    });
-
-    // @ts-expect-error This SHOULD error
-    myIntegration({});
-  });
-
-  it('works with integration options', () => {
-    const myIntegration = makeIntegrationFn((_options: { xxx: string }) => {
-      return {
-        name: 'testName'
-      };
-    });
-
-    const integration = myIntegration({ xxx: 'aa' });
-    expect(integration).toEqual({
-      name: 'testName',
-    });
-
-    // @ts-expect-error This SHOULD error
-    myIntegration();
-    // @ts-expect-error This SHOULD error
-    myIntegration({});
-  });
-
-  it('works with integration hooks', () => {
-    const setup = jest.fn();
-    const setupOnce = jest.fn();
-    const processEvent = jest.fn();
-    const preprocessEvent = jest.fn();
 
-    const myIntegration = makeIntegrationFn(() => {
-      return {
-        name: 'testName',
-        setup,
-        setupOnce,
-        processEvent,
-        preprocessEvent,
-      };
-    });
-
-    const integration = myIntegration();
-    expect(integration).toEqual({
-      name: 'testName',
-      setup,
-      setupOnce,
-      processEvent,
-      preprocessEvent,
-    });
-
-    // @ts-expect-error This SHOULD error
-    makeIntegrationFn('testName', () => ({ other: 'aha' }));
-  });
-});
 
 describe('convertIntegrationFnToClass', () => {
   /* eslint-disable deprecation/deprecation */
   it('works with a minimal integration', () => {
-    const integrationFn = makeIntegrationFn(() => ({ name: 'testName'}));
+    const integrationFn = () => ({ name: 'testName'});
 
     const IntegrationClass = convertIntegrationFnToClass('testName', integrationFn);
 
@@ -742,7 +678,7 @@ describe('convertIntegrationFnToClass', () => {
     const processEvent = jest.fn();
     const preprocessEvent = jest.fn();
 
-    const integrationFn = makeIntegrationFn( () => {
+    const integrationFn = () => {
       return {
         name: 'testName',
         setup,
@@ -750,7 +686,7 @@ describe('convertIntegrationFnToClass', () => {
         processEvent,
         preprocessEvent,
       };
-    });
+    };
 
     const IntegrationClass = convertIntegrationFnToClass('testName', integrationFn);
 

From a2901ce513856e5b319ae1d652b987218bb9d445 Mon Sep 17 00:00:00 2001
From: Francesco Novy <francesco.novy@sentry.io>
Date: Fri, 15 Dec 2023 12:50:21 +0100
Subject: [PATCH 12/12] fix linting

---
 packages/core/src/integration.ts                 | 10 +---------
 packages/core/src/integrations/inboundfilters.ts |  4 ++--
 packages/core/test/lib/integration.test.ts       |  4 +---
 3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/packages/core/src/integration.ts b/packages/core/src/integration.ts
index 9316039e4917..57adc3d33c36 100644
--- a/packages/core/src/integration.ts
+++ b/packages/core/src/integration.ts
@@ -1,12 +1,4 @@
-import type {
-  Client,
-  Event,
-  EventHint,
-  Integration,
-  IntegrationClass,
-  IntegrationFn,
-  Options,
-} from '@sentry/types';
+import type { Client, Event, EventHint, Integration, IntegrationClass, IntegrationFn, Options } from '@sentry/types';
 import { arrayify, logger } from '@sentry/utils';
 
 import { DEBUG_BUILD } from './debug-build';
diff --git a/packages/core/src/integrations/inboundfilters.ts b/packages/core/src/integrations/inboundfilters.ts
index df560175ad78..57c0387b25e4 100644
--- a/packages/core/src/integrations/inboundfilters.ts
+++ b/packages/core/src/integrations/inboundfilters.ts
@@ -1,4 +1,4 @@
-import type {  Event, IntegrationFn, StackFrame } from '@sentry/types';
+import type { Event, IntegrationFn, StackFrame } from '@sentry/types';
 import { getEventDescription, logger, stringMatchesSomePattern } from '@sentry/utils';
 
 import { DEBUG_BUILD } from '../debug-build';
@@ -39,7 +39,7 @@ const inboundFiltersIntegration: IntegrationFn = (options: Partial<InboundFilter
       return _shouldDropEvent(event, mergedOptions) ? null : event;
     },
   };
-}
+};
 
 /** Inbound filters configurable by the user */
 // eslint-disable-next-line deprecation/deprecation
diff --git a/packages/core/test/lib/integration.test.ts b/packages/core/test/lib/integration.test.ts
index 9c767189964e..65bf30483d86 100644
--- a/packages/core/test/lib/integration.test.ts
+++ b/packages/core/test/lib/integration.test.ts
@@ -654,12 +654,10 @@ describe('addIntegration', () => {
   });
 });
 
-
-
 describe('convertIntegrationFnToClass', () => {
   /* eslint-disable deprecation/deprecation */
   it('works with a minimal integration', () => {
-    const integrationFn = () => ({ name: 'testName'});
+    const integrationFn = () => ({ name: 'testName' });
 
     const IntegrationClass = convertIntegrationFnToClass('testName', integrationFn);