fix: lifecycle should be a singleton across core versions

src/lifecycleEvents.ts

@@ -12,6 +12,10 @@ import * as Debug from 'debug';
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 type callback = (data: any) => Promise<void>;
 
+declare const global: {
+  salesforceCoreLifecycle?: Lifecycle;
+};
+
 /**
  * An asynchronous event listener and emitter that follows the singleton pattern. The singleton pattern allows lifecycle
  * events to be emitted from deep within a library and still be consumed by any other library or tool. It allows other
@@ -31,7 +35,6 @@ type callback = (data: any) => Promise<void>;
  * ```
  */
 export class Lifecycle {
-  private static instance: Lifecycle;
   private debug = Debug(`sfdx:${this.constructor.name}`);
   private readonly listeners: Dictionary<callback[]>;
 
@@ -42,10 +45,17 @@ export class Lifecycle {
    * Retrieve the singleton instance of this class so that all listeners and emitters can interact from any library or tool
    */
   public static getInstance(): Lifecycle {
-    if (!this.instance) {
-      this.instance = new Lifecycle();
+    // Across a npm dependency tree, there may be a LOT of versions of @salesforce/core. We want to ensure that consumers are notified when
+    // listening on a lifecycle event that is fired by a different version of @salesforce/core. Adding the instance on the global object will
+    // ensure this. Note: There needs to be version checking up update lifecycle to the newer version if ANYTHING is ever added to this class.
+    // One way this can be done by adding a version = require(../package.json).version to the Lifecycle class, then checking that here.
+    // For example, if instance is created with @salesforce/core@2.12.2 and something is added in 2.14.0, someone who depends on version 2.14.0
+    // may get an instance that was created with 2.12.2.
+    // Nothing should EVER be removed, even across major versions.
+    if (!global.salesforceCoreLifecycle) {
+      global.salesforceCoreLifecycle = new Lifecycle();
     }
-    return this.instance;
+    return global.salesforceCoreLifecycle;
   }
 
   /**

test/unit/lifecycleEventsTest.ts

@@ -32,7 +32,19 @@ describe('lifecycleEvents', () => {
     chai.assert(Lifecycle.getInstance() === Lifecycle.getInstance());
   });
 
-  it('succsssful event registration and emitting causes the callback to be called', async () => {
+  it('getInstance is on the global object to protect against npm version dependency mismatch', async () => {
+    // @ts-ignore don't declare the type in the test
+    chai.assert(Lifecycle.getInstance() === global.salesforceCoreLifecycle);
+  });
+
+  it('has not changed', async () => {
+    chai.assert(
+      Object.getOwnPropertyNames(Lifecycle.prototype).length === 5,
+      'Lifecycle can not be changed without adding version support to update the instance to the latest version. See note in Lifecycle.getInstance'
+    );
+  });
+
+  it('successful event registration and emitting causes the callback to be called', async () => {
     Lifecycle.getInstance().on('test1', async (result) => {
       fake.bar('test1', result);
     });

yarn.lock

@@ -2066,7 +2066,7 @@ debug@^2.2.0, debug@^2.3.3, debug@^2.6.9:
   dependencies:
     ms "2.0.0"
 
-debuglog@*, debuglog@^1.0.1:
+debuglog@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/debuglog/-/debuglog-1.0.1.tgz#aa24ffb9ac3df9a2351837cfb2d279360cd78492"
   integrity sha1-qiT/uaw9+aI1GDfPstJ5NgzXhJI=
@@ -3613,7 +3613,7 @@ import-lazy@^2.1.0:
   resolved "https://registry.yarnpkg.com/import-lazy/-/import-lazy-2.1.0.tgz#05698e3d45c88e8d7e9d92cb0584e77f096f3e43"
   integrity sha1-BWmOPUXIjo1+nZLLBYTnfwlvPkM=
 
-imurmurhash@*, imurmurhash@^0.1.4:
+imurmurhash@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/imurmurhash/-/imurmurhash-0.1.4.tgz#9218b9b2b928a238b13dc4fb6b6d576f231453ea"
   integrity sha1-khi5srkoojixPcT7a21XbyMUU+o=
@@ -4541,11 +4541,6 @@ lockfile@^1.0.4:
   dependencies:
     signal-exit "^3.0.2"
 
-lodash._baseindexof@*:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/lodash._baseindexof/-/lodash._baseindexof-3.1.0.tgz#fe52b53a1c6761e42618d654e4a25789ed61822c"
-  integrity sha1-/lK1OhxnYeQmGNZU5KJXie1hgiw=
-
 lodash._baseuniq@~4.6.0:
   version "4.6.0"
   resolved "https://registry.yarnpkg.com/lodash._baseuniq/-/lodash._baseuniq-4.6.0.tgz#0ebb44e456814af7905c6212fa2c9b2d51b841e8"
@@ -4554,33 +4549,11 @@ lodash._baseuniq@~4.6.0:
     lodash._createset "~4.0.0"
     lodash._root "~3.0.0"
 
-lodash._bindcallback@*:
-  version "3.0.1"
-  resolved "https://registry.yarnpkg.com/lodash._bindcallback/-/lodash._bindcallback-3.0.1.tgz#e531c27644cf8b57a99e17ed95b35c748789392e"
-  integrity sha1-5THCdkTPi1epnhftlbNcdIeJOS4=
-
-lodash._cacheindexof@*:
-  version "3.0.2"
-  resolved "https://registry.yarnpkg.com/lodash._cacheindexof/-/lodash._cacheindexof-3.0.2.tgz#3dc69ac82498d2ee5e3ce56091bafd2adc7bde92"
-  integrity sha1-PcaayCSY0u5ePOVgkbr9Ktx73pI=
-
-lodash._createcache@*:
-  version "3.1.2"
-  resolved "https://registry.yarnpkg.com/lodash._createcache/-/lodash._createcache-3.1.2.tgz#56d6a064017625e79ebca6b8018e17440bdcf093"
-  integrity sha1-VtagZAF2JeeevKa4AY4XRAvc8JM=
-  dependencies:
-    lodash._getnative "^3.0.0"
-
 lodash._createset@~4.0.0:
   version "4.0.3"
   resolved "https://registry.yarnpkg.com/lodash._createset/-/lodash._createset-4.0.3.tgz#0f4659fbb09d75194fa9e2b88a6644d363c9fe26"
   integrity sha1-D0ZZ+7CddRlPqeK4imZE02PJ/iY=
 
-lodash._getnative@*, lodash._getnative@^3.0.0:
-  version "3.9.1"
-  resolved "https://registry.yarnpkg.com/lodash._getnative/-/lodash._getnative-3.9.1.tgz#570bc7dede46d61cdcde687d65d3eecbaa3aaff5"
-  integrity sha1-VwvH3t5G1hzc3mh9ZdPuy6o6r/U=
-
 lodash._reinterpolate@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/lodash._reinterpolate/-/lodash._reinterpolate-3.0.0.tgz#0ccf2d89166af03b3663c796538b75ac6e114d9d"
@@ -4661,11 +4634,6 @@ lodash.once@^4.0.0:
   resolved "https://registry.yarnpkg.com/lodash.once/-/lodash.once-4.1.1.tgz#0dd3971213c7c56df880977d504c88fb471a97ac"
   integrity sha1-DdOXEhPHxW34gJd9UEyI+0cal6w=
 
-lodash.restparam@*:
-  version "3.6.1"
-  resolved "https://registry.yarnpkg.com/lodash.restparam/-/lodash.restparam-3.6.1.tgz#936a4e309ef330a7645ed4145986c85ae5b20805"
-  integrity sha1-k2pOMJ7zMKdkXtQUWYbIWuWyCAU=
-
 lodash.set@^4.3.2:
   version "4.3.2"
   resolved "https://registry.yarnpkg.com/lodash.set/-/lodash.set-4.3.2.tgz#d8757b1da807dde24816b0d6a84bea1a76230b23"