feat: Use plugin metadata for flat config serialization

docs/src/extend/plugins.md

@@ -18,6 +18,34 @@ Each plugin is an npm module with a name in the format of `eslint-plugin-<plugin
 
 The easiest way to start creating a plugin is to use the [Yeoman generator](https://www.npmjs.com/package/generator-eslint). The generator will guide you through setting up the skeleton of a plugin.
 
+### Metadata in Plugins
+
+For easier debugging and more effective caching of plugins, it's recommended to provide a name and version in a `meta` object at the root of your plugin, like this:
+
+```js
+// preferred location of name and version
+module.exports = {
+    meta: {
+        name: "eslint-plugin-custom",
+        version: "1.2.3"
+    }
+};
+```
+
+The `meta.name` property should match the npm package name for your plugin and the `meta.version` property should match the npm package version for your plugin. The easiest way to accomplish this is by reading this information from your `package.json`.
+
+As an alternative, you can also expose `name` and `version` properties at the root of your plugin, such as:
+
+```js
+// alternate location of name and version
+module.exports = {
+    name: "eslint-plugin-custom",
+    version: "1.2.3"
+};
+```
+
+While the `meta` object is the preferred way to provide the plugin name and version, this format is also acceptable and is provided for backward compatibility.
+
 ### Rules in Plugins
 
 Plugins can expose custom rules for use in ESLint. To do so, the plugin must export a `rules` object containing a key-value mapping of rule ID to rule. The rule ID does not have to follow any naming convention (so it can just be `dollar-sign`, for instance). To learn more about creating custom rules in plugins, refer to [Custom Rules](custom-rules).

lib/config/flat-config-array.js

@@ -245,7 +245,16 @@ class FlatConfigArray extends ConfigArray {
 
                 return {
                     ...this,
-                    plugins: Object.keys(plugins),
+                    plugins: Object.entries(plugins).map(([namespace, plugin]) => {
+
+                        const pluginId = getObjectId(plugin);
+
+                        if (!pluginId) {
+                            return namespace;
+                        }
+
+                        return `${namespace}:${pluginId}`;
+                    }),
                     languageOptions: {
                         ...languageOptions,
                         parser: parserName

tests/lib/config/flat-config-array.js

@@ -221,6 +221,72 @@ describe("FlatConfigArray", () => {
             assert.strictEqual(stringify(actual), stringify(expected));
         });
 
+        it("should convert config with plugin name/version into normalized JSON object", () => {
+
+            const configs = new FlatConfigArray([{
+                plugins: {
+                    a: {},
+                    b: {
+                        name: "b-plugin",
+                        version: "2.3.1"
+                    }
+                }
+            }]);
+
+            configs.normalizeSync();
+
+            const config = configs.getConfig("foo.js");
+            const expected = {
+                plugins: ["@", "a", "b:b-plugin@2.3.1"],
+                languageOptions: {
+                    ecmaVersion: "latest",
+                    sourceType: "module",
+                    parser: `espree@${espree.version}`,
+                    parserOptions: {}
+                },
+                processor: void 0
+            };
+            const actual = config.toJSON();
+
+            assert.deepStrictEqual(actual, expected);
+
+            assert.strictEqual(stringify(actual), stringify(expected));
+        });
+
+        it("should convert config with plugin meta into normalized JSON object", () => {
+
+            const configs = new FlatConfigArray([{
+                plugins: {
+                    a: {},
+                    b: {
+                        meta: {
+                            name: "b-plugin",
+                            version: "2.3.1"
+                        }
+                    }
+                }
+            }]);
+
+            configs.normalizeSync();
+
+            const config = configs.getConfig("foo.js");
+            const expected = {
+                plugins: ["@", "a", "b:b-plugin@2.3.1"],
+                languageOptions: {
+                    ecmaVersion: "latest",
+                    sourceType: "module",
+                    parser: `espree@${espree.version}`,
+                    parserOptions: {}
+                },
+                processor: void 0
+            };
+            const actual = config.toJSON();
+
+            assert.deepStrictEqual(actual, expected);
+
+            assert.strictEqual(stringify(actual), stringify(expected));
+        });
+
         it("should throw an error when config with unnamed parser object is normalized", () => {
 
             const configs = new FlatConfigArray([{