fix: YAML parser error from diff-style lines in nested lists

pr_agent/algo/utils.py

@@ -868,6 +868,44 @@ def try_fix_yaml(response_text: str,
     except:
         pass
 
+    # 5.5 fallback - try to normalize diff-style removal markers ('-') within list items
+    response_text_lines_copy = response_text_lines.copy()
+    modified = False
+
+    for i, line in enumerate(response_text_lines_copy):
+        if line.startswith('+'):
+            response_text_lines_copy[i] = ' ' + line[1:]
+            modified = True
+
+    # normalize lines starting with '-'. Distinguish real YAML list items from diff deletions.
+    for i, line in enumerate(response_text_lines_copy):
+        if not line.startswith('-'):
+            continue
+
+        remainder = line[1:]
+        if line.startswith('- '):
+            second_char = remainder[1] if len(remainder) > 1 else ''
+            if second_char and second_char not in (' ', '\t', '+', '-'):
+                continue # real list item → keep as-is
+
+        # treat it as a diff "removed" marker inside block content
+        cleaned = remainder
+        while cleaned and cleaned[0] in ('+', '-'):
+            cleaned = cleaned[1:]
+        if cleaned and cleaned[0] not in (' ', '\t'):
+            cleaned = ' ' + cleaned
+        if cleaned != line:
+            response_text_lines_copy[i] = cleaned
+            modified = True
+    if modified:
+        try:
+            data = yaml.safe_load('\n'.join(response_text_lines_copy))
+            get_logger().info("Successfully parsed AI prediction after normalizing diff removal markers")
+            return data
+        except:
+            pass
+
+
     # sixth fallback - replace tabs with spaces
     if '\t' in response_text:
         response_text_copy = copy.deepcopy(response_text)

tests/unittest/test_try_fix_yaml.py

@@ -244,3 +244,36 @@ def test_wrong_indentation_code_block_scalar(self):
 '''
         expected_output = {'code_suggestions': [{'relevant_file': 'a.c\n', 'existing_code': '  int sum(int a, int b) {\n    return a + b;\n  }\n\n  int sub(int a, int b) {\n    return a - b;\n  }\n'}]}
         assert try_fix_yaml(review_text, first_key='code_suggestions', last_key='existing_code') == expected_output
+
+    def test_diff_markers_removed_within_list_item(self):
+        """
+            Ensures diff-style '-' markers nested inside list items are normalised so the YAML parses
+            into the expected structure.
+        """
+        review_text = '''\
+code_suggestions:
+- relevant_file: |
+    example.rb
+  existing_code: |
++    puts 'hello'
++    puts 'world'
+- relevant_file: |
+-    example.py
+-  existing_code: |
+-+    print('hello')
+-+    print('world')
+'''
+        expected_output = {
+            'code_suggestions': [
+                {
+                    'relevant_file': 'example.rb\n',
+                    'existing_code': "puts 'hello'\nputs 'world'\n"
+                },
+                {
+                    'relevant_file': 'example.py\n',
+                    'existing_code': "print('hello')\nprint('world')\n"
+                }
+            ]
+        }
+
+        assert try_fix_yaml(review_text, first_key='code_suggestions', last_key='existing_code') == expected_output