feat(angular): Log warning if SDK is used with an older Angular version than officially supported

MIGRATION.md

@@ -129,7 +129,11 @@ The Sentry Angular SDK (`@sentry/angular`) is now compiled with the Angular comp
 
 ### Angular Version Compatibility
 
-Given the forward compatibility of the Angular compiler, v7 of our SDK will only work with Angular 10 and above. Previously, it was possible to use the SDK with versions <10, although we officially only supported Angular 10-13 as peer dependencies. If you are using Angular <10 in your project, we recommend staying on the latest 6.x version until you can upgrade your Angular version.
+As in v6, we continue to list Angular 10-13 in our peer dependencies, meaning that these are the Angular versions we officially support.
+If you are using v7 with Angular <10 in your project and you experience problems, we recommend staying on the latest 6.x
+version until you can upgrade your Angular version. As v7 of our SDK is compiled with the Angular 10 compiler and we upgraded
+our Typescript version, the SDK will work with Angular 10 and above. Tests have shown that Angular 9 seems to work as well
+(use at your own risk) but we recommend upgrading to a more recent Angular version.
 
 ### Import Changes
 

packages/angular/README.md

@@ -14,8 +14,7 @@
 
 ## Angular Version Compatibility
 
-For Angular 10-13 use the latest version of the Sentry Angular SDK. In case
-you are using an Angular 9 or earlier, use version 6.x of the SDK as newer versions do not support Angular <10.
+The latest version of this SDK officially supports Angular 10-13. If you are using an older version of Angular and experience problems with the Angular SDK, we recommend downgrading the SDK to version 6.x.
 
 ## General
 

packages/angular/src/constants.ts

@@ -3,3 +3,8 @@ export const ANGULAR_ROUTING_OP = 'ui.angular.routing';
 export const ANGULAR_INIT_OP = 'ui.angular.init';
 
 export const ANGULAR_OP = 'ui.angular';
+
+/**
+ * Minimum Angular version this SDK supports
+ */
+export const ANGULAR_MINIMUM_VERSION = 10;

packages/angular/src/sdk.ts

@@ -1,4 +1,9 @@
+import { VERSION } from '@angular/core';
 import { BrowserOptions, init as browserInit, SDK_VERSION } from '@sentry/browser';
+import { logger } from '@sentry/utils';
+
+import { ANGULAR_MINIMUM_VERSION } from './constants';
+import { IS_DEBUG_BUILD } from './flags';
 
 /**
  * Inits the Angular SDK
@@ -15,5 +20,20 @@ export function init(options: BrowserOptions): void {
     ],
     version: SDK_VERSION,
   };
+  checkAngularVersion();
   browserInit(options);
 }
+
+function checkAngularVersion(): void {
+  if (VERSION && VERSION.major) {
+    const major = parseInt(VERSION.major, 10);
+    if (major < ANGULAR_MINIMUM_VERSION) {
+      IS_DEBUG_BUILD &&
+        logger.warn(
+          `The Sentry SDK does not officially support Angular ${major}.`,
+          `This version of the Sentry SDK supports Angular ${ANGULAR_MINIMUM_VERSION} and above.`,
+          'Please consider upgrading your Angular version or downgrading the Sentry SDK.',
+        );
+    }
+  }
+}