Revert "Fix: clone config before validating (fixes #12592) (#13034)"

This reverts commit 7fb45cf.

lib/cli-engine/config-array-factory.js

@@ -697,33 +697,6 @@ class ConfigArrayFactory {
             ctx.matchBasePath
         );
 
-        /**
-         * Cloning the rule's config as we are setting `useDefaults` to true`
-         * which mutates the config with its default value if present. And when we
-         * refer to a same variable for config for different rules, that referred variable will
-         * be mutated and it will be used for both.
-         *
-         * Example:
-         *
-         * const commonRuleConfig  = ['error', {}];
-         *
-         * Now if we use this variable as a config for rules like this
-         *
-         * {
-         *      rules: {
-         *          "a" : commonRuleConfig,
-         *          "b" : commonRuleConfig,
-         *      }
-         * }
-         *
-         * And if these rules have default values in their schema, their
-         * config will be mutated with default values, the mutated `commonRuleConfig` will be used for `b` as well and it probably
-         * throw schema voilation errors.
-         *
-         * Refer https://github.com/eslint/eslint/issues/12592
-         */
-        const clonedRulesConfig = rules && JSON.parse(JSON.stringify((rules)));
-
         // Flatten `extends`.
         for (const extendName of extendList.filter(Boolean)) {
             yield* this._loadExtends(extendName, ctx);
@@ -758,7 +731,7 @@ class ConfigArrayFactory {
             processor,
             reportUnusedDisableDirectives,
             root,
-            rules: clonedRulesConfig,
+            rules,
             settings
         };
 

tests/lib/cli.js

@@ -187,7 +187,6 @@ describe("cli", () => {
         });
     });
 
-
     describe("when given a config with environment set to Node.js", () => {
         it("should execute without any errors", async () => {
             const configPath = getFixturePath("configurations", "env-node.json");
@@ -1161,58 +1160,4 @@ describe("cli", () => {
         });
     });
 
-    describe("testing the cloned config", () => {
-        describe("config file and input file", () => {
-            it("should not modify original configuration object", async () => {
-                const configPath = getFixturePath("config-file", "cloned-config", "eslintConfig.js");
-                const filePath = getFixturePath("config-file", "cloned-config", "index.js");
-                const args = `--config ${configPath} ${filePath}`;
-
-                const exit = await cli.execute(args);
-
-                assert.strictEqual(exit, 0);
-            });
-        });
-
-        describe("config file and input file", () => {
-            it("should exit with 1 as camelcase has wrong property type", async () => {
-                const configPath = getFixturePath("config-file", "cloned-config", "eslintConfigFail.js");
-                const filePath = getFixturePath("config-file", "cloned-config", "index.js");
-                const args = `--config ${configPath} ${filePath}`;
-
-                try {
-                    await cli.execute(args);
-                } catch (error) {
-                    assert.strictEqual(/Configuration for rule "camelcase" is invalid:/u.test(error), true);
-                }
-
-            });
-        });
-
-        describe("inline config and input file", () => {
-            it("should not modify original configuration object", async () => {
-                const filePath = getFixturePath("config-file", "cloned-config", "inlineText.js");
-                const args = `${filePath}`;
-
-                const exit = await cli.execute(args);
-
-                assert.strictEqual(exit, 0);
-            });
-        });
-
-    });
-
-    describe("handling circular reference while cloning", () => {
-        it("should handle circular ref", async () => {
-            const configPath = getFixturePath("config-file", "cloned-config", "circularRefEslintConfig.js");
-            const filePath = getFixturePath("config-file", "cloned-config", "index.js");
-            const args = `--config ${configPath} ${filePath}`;
-
-            try {
-                await cli.execute(args);
-            } catch (error) {
-                assert.instanceOf(error, Error);
-            }
-        });
-    });
 });