From 5aa9c499da48b2d3187270d5d8ece71ad7521f56 Mon Sep 17 00:00:00 2001
From: Bryan Mishkin <698306+bmish@users.noreply.github.com>
Date: Wed, 20 Dec 2023 11:36:18 -0500
Subject: [PATCH] feat!: check for parsing errors in suggestion fixes (#16639)

* feat!: check for parsing errors in suggestion fixes

* revert RuleTester changes
---
 lib/rule-tester/flat-rule-tester.js       | 15 ++++++++-
 tests/lib/rule-tester/flat-rule-tester.js | 41 +++++++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/lib/rule-tester/flat-rule-tester.js b/lib/rule-tester/flat-rule-tester.js
index c790dab69e7..0a127c749a0 100644
--- a/lib/rule-tester/flat-rule-tester.js
+++ b/lib/rule-tester/flat-rule-tester.js
@@ -764,7 +764,9 @@ class FlatRuleTester {
                 messages,
                 output,
                 beforeAST,
-                afterAST: cloneDeeplyExcludesParent(afterAST)
+                afterAST: cloneDeeplyExcludesParent(afterAST),
+                configs,
+                filename
             };
         }
 
@@ -1050,6 +1052,17 @@ class FlatRuleTester {
                                     if (hasOwnProperty(expectedSuggestion, "output")) {
                                         const codeWithAppliedSuggestion = SourceCodeFixer.applyFixes(item.code, [actualSuggestion]).output;
 
+                                        // Verify if suggestion fix makes a syntax error or not.
+                                        const errorMessageInSuggestion =
+                                            linter.verify(codeWithAppliedSuggestion, result.configs, result.filename).find(m => m.fatal);
+
+                                        assert(!errorMessageInSuggestion, [
+                                            "A fatal parsing error occurred in suggestion fix.",
+                                            `Error: ${errorMessageInSuggestion && errorMessageInSuggestion.message}`,
+                                            "Suggestion output:",
+                                            codeWithAppliedSuggestion
+                                        ].join("\n"));
+
                                         assert.strictEqual(codeWithAppliedSuggestion, expectedSuggestion.output, `Expected the applied suggestion fix to match the test suggestion output for suggestion at index: ${index} on error with message: "${message.message}"`);
                                     }
                                 });
diff --git a/tests/lib/rule-tester/flat-rule-tester.js b/tests/lib/rule-tester/flat-rule-tester.js
index fe97bd2c851..5f47ce1fe4b 100644
--- a/tests/lib/rule-tester/flat-rule-tester.js
+++ b/tests/lib/rule-tester/flat-rule-tester.js
@@ -2020,6 +2020,47 @@ describe("FlatRuleTester", () => {
             }, "Error should have 2 suggestions. Instead found 1 suggestions");
         });
 
+        it("should throw if suggestion fix made a syntax error.", () => {
+            assert.throw(() => {
+                ruleTester.run(
+                    "foo",
+                    {
+                        meta: { hasSuggestions: true },
+                        create(context) {
+                            return {
+                                Identifier(node) {
+                                    context.report({
+                                        node,
+                                        message: "make a syntax error",
+                                        suggest: [
+                                            {
+                                                desc: "make a syntax error",
+                                                fix(fixer) {
+                                                    return fixer.replaceText(node, "one two");
+                                                }
+                                            }
+                                        ]
+                                    });
+                                }
+                            };
+                        }
+                    },
+                    {
+                        valid: [""],
+                        invalid: [{
+                            code: "one()",
+                            errors: [{
+                                suggestions: [{
+                                    desc: "make a syntax error",
+                                    output: "one two()"
+                                }]
+                            }]
+                        }]
+                    }
+                );
+            }, /A fatal parsing error occurred in suggestion fix\.\nError: .+\nSuggestion output:\n.+/u);
+        });
+
         it("should throw if the suggestion description doesn't match", () => {
             assert.throws(() => {
                 ruleTester.run("suggestions-basic", require("../../fixtures/testers/rule-tester/suggestions").basic, {