From 4e3463d28d49397a246169a16246349cce518554 Mon Sep 17 00:00:00 2001
From: Jason Green <jasoniangreen@gmail.com>
Date: Wed, 7 Aug 2024 21:32:01 +0100
Subject: [PATCH] fix: include original error and add extra info

---
 lib/vocabularies/code.ts                            | 2 +-
 lib/vocabularies/validation/pattern.ts              | 2 +-
 spec/issues/2477_informative_pattern_errors.spec.ts | 9 ++++++---
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/lib/vocabularies/code.ts b/lib/vocabularies/code.ts
index 1710b4aa3..63ad9022d 100644
--- a/lib/vocabularies/code.ts
+++ b/lib/vocabularies/code.ts
@@ -100,7 +100,7 @@ export function usePattern({gen, it: {opts, errSchemaPath}}: KeywordCxt, pattern
   try {
     rx = new RegExp(pattern, u)
   } catch (e) {
-    throw new Error(`Invalid regular expression: ${pattern} at ${errSchemaPath}`)
+    throw new Error(`${(e as Error).message} | pattern ${pattern} at ${errSchemaPath}`)
   }
   rx = regExp(pattern, u)
 
diff --git a/lib/vocabularies/validation/pattern.ts b/lib/vocabularies/validation/pattern.ts
index 947cd72ec..e42997727 100644
--- a/lib/vocabularies/validation/pattern.ts
+++ b/lib/vocabularies/validation/pattern.ts
@@ -24,7 +24,7 @@ const def: CodeKeywordDefinition = {
         try {
           return new RegExp(${schemaCode}, ${u})
         } catch (e) {
-          throw new Error('Invalid regular expression: ' + ${schemaCode} + ' at ' + ${it.errSchemaPath})
+          throw new Error(e.message + ' | pattern ' + ${schemaCode} + ' at ' + ${it.errSchemaPath})
         }
       })()`
       : usePattern(cxt, schema)
diff --git a/spec/issues/2477_informative_pattern_errors.spec.ts b/spec/issues/2477_informative_pattern_errors.spec.ts
index aa19ec401..facc6e450 100644
--- a/spec/issues/2477_informative_pattern_errors.spec.ts
+++ b/spec/issues/2477_informative_pattern_errors.spec.ts
@@ -13,7 +13,10 @@ describe("Invalid regexp patterns should throw more informative errors (issue #2
     assert.throws(
       () => ajv.compile(rootSchema),
       (thrown: unknown) => {
-        assert.equal((thrown as Error).message, "Invalid regular expression: ^[0-9]{2-4} at #")
+        assert.equal(
+          (thrown as Error).message,
+          "Invalid regular expression: /^[0-9]{2-4}/: Incomplete quantifier | pattern ^[0-9]{2-4} at #"
+        )
         return true
       }
     )
@@ -30,7 +33,7 @@ describe("Invalid regexp patterns should throw more informative errors (issue #2
       (thrown: unknown) => {
         assert.equal(
           (thrown as Error).message,
-          "Invalid regular expression: ^[0-9]{2-4} at #/properties/foo"
+          "Invalid regular expression: /^[0-9]{2-4}/: Incomplete quantifier | pattern ^[0-9]{2-4} at #/properties/foo"
         )
         return true
       }
@@ -52,7 +55,7 @@ describe("Invalid regexp patterns should throw more informative errors (issue #2
       (thrown: unknown) => {
         assert.equal(
           (thrown as Error).message,
-          "Invalid regular expression: ^[0-9]{2-4} at #/properties/string"
+          "Invalid regular expression: /^[0-9]{2-4}/: Incomplete quantifier | pattern ^[0-9]{2-4} at #/properties/string"
         )
         return true
       }