From e5ea3bb4da2ecc064c023f785fde04be08af0517 Mon Sep 17 00:00:00 2001
From: Eric Fitzgerald <github@efitz.net>
Date: Sat, 29 Nov 2025 11:22:12 -0500
Subject: [PATCH] fix: Prevent negative count in
 SimpleJsonFormatter.formatJsonString
MIME-Version: 1.0
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Fixed IllegalArgumentException when formatting JSON with extra closing brackets.
The formatter was calling String.repeat() with a negative value when indentLevel
reached 0 and tried to calculate (indentLevel - 1).

Changes:
- Added Math.max(0, indentLevel - 1) guard in SimpleJsonFormatter.java:57
- Added 3 test cases for malformed JSON edge cases
- All 8 tests now pass

Fixes error when generating HTML reports for responses with malformed JSON.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 .../endava/cats/util/SimpleJsonFormatter.java |  2 +-
 .../cats/util/SimpleJsonFormatterTest.java    | 23 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/endava/cats/util/SimpleJsonFormatter.java b/src/main/java/com/endava/cats/util/SimpleJsonFormatter.java
index de3dcd93..ba9c8e03 100644
--- a/src/main/java/com/endava/cats/util/SimpleJsonFormatter.java
+++ b/src/main/java/com/endava/cats/util/SimpleJsonFormatter.java
@@ -54,7 +54,7 @@ private static String formatJsonString(String jsonStr) {
                     }
                     case '}', ']' -> {
                         if (prevChar != '{' && prevChar != '[' && prevChar != '\n') {
-                            formatted.append('\n').append(indent.repeat(indentLevel - 1));
+                            formatted.append('\n').append(indent.repeat(Math.max(0, indentLevel - 1)));
                         }
                         indentLevel--;
                         formatted.append(currentChar);
diff --git a/src/test/java/com/endava/cats/util/SimpleJsonFormatterTest.java b/src/test/java/com/endava/cats/util/SimpleJsonFormatterTest.java
index 4ea0fb59..3636c0e9 100644
--- a/src/test/java/com/endava/cats/util/SimpleJsonFormatterTest.java
+++ b/src/test/java/com/endava/cats/util/SimpleJsonFormatterTest.java
@@ -44,4 +44,27 @@ void shouldHandleEscapedQuotesInJsonString() {
         String result = SimpleJsonFormatter.formatJson(input);
         assertThat(result).isEqualTo(expected);
     }
+
+    @Test
+    void shouldHandleMalformedJsonWithExtraClosingBrackets() {
+        String input = "{\"key\":\"value\"}}";
+        String result = SimpleJsonFormatter.formatJson(input);
+        assertThat(result).isNotNull();
+    }
+
+    @Test
+    void shouldHandleMalformedJsonWithExtraClosingSquareBrackets() {
+        String input = "[1,2,3]]";
+        String result = SimpleJsonFormatter.formatJson(input);
+        assertThat(result).isNotNull();
+    }
+
+    @Test
+    void shouldHandleNestedStructures() {
+        String input = "{\"outer\":{\"inner\":{\"deep\":\"value\"}}}";
+        String result = SimpleJsonFormatter.formatJson(input);
+        assertThat(result).contains("\"outer\":");
+        assertThat(result).contains("\"inner\":");
+        assertThat(result).contains("\"deep\": \"value\"");
+    }
 }