fix: fix CONTRIBUTING.md placeholders, bare except clauses, and add convert.py tests (#3485) [skip ci]

* docs: fix codestyle placeholders in CONTRIBUTING.md

Replace unresolved {codestyle} and {URLofCodestyle} template
variables with Ruff, the project's actual linter/formatter
as configured in .pre-commit-config.yaml.

* fix: replace bare except clauses with specific exception types

- quantization.py: use except ImportError for optional torchao imports
  (consistent with line 48 which already uses ImportError correctly)
- cli/config.py: use except (RuntimeError, AssertionError) for CUDA
  device property query

Prevents masking unrelated errors like KeyboardInterrupt or SystemExit.

* test: add unit tests for convert.py JSON/JSONL utilities

Cover FileReader, FileWriter, StdoutWriter, JsonParser,
JsonlSerializer, and JsonToJsonlConverter with 8 test cases
including roundtrip and edge case (empty list) scenarios.

Previously this module had zero test coverage.

* fix: address CodeRabbit review feedback

- quantization.py: catch (ImportError, RuntimeError) for optional
  torchao imports; CUDA wheel/GPU mismatches raise RuntimeError,
  not ImportError
- convert.py: remove unused output_file_path parameter from
  JsonToJsonlConverter.convert() — FileWriter already holds the
  output path from construction
- tests/test_convert.py: update call site to match new signature

.github/CONTRIBUTING.md

@@ -68,7 +68,7 @@ You can skip certain CI checks by including specific keywords in your commit mes
 
 ### Code Style
 
-axolotl uses [{codestyle}]({URLofCodestyle}) as its code style guide. Please ensure that your code follows these guidelines.
+axolotl uses [Ruff](https://docs.astral.sh/ruff/) as its code style guide. Please ensure that your code follows these guidelines.
 
 Use the pre-commit linter to ensure that your code is formatted consistently.
 ```bash
@@ -83,6 +83,6 @@ Write clear and concise commit messages that briefly describe the changes made i
 
 - [GitHub Help](https://help.github.com/)
 - [GitHub Pull Request Documentation](https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests)
-- [{codestyle}]({URLofCodestyle})
+- [Ruff](https://docs.astral.sh/ruff/)
 
 Thank you once again for your interest in contributing to axolotl. We look forward to collaborating with you and creating an even better project together!

src/axolotl/cli/config.py

@@ -300,7 +300,7 @@ def load_cfg(
     try:
         device_props = torch.cuda.get_device_properties("cuda")
         gpu_version = "sm_" + str(device_props.major) + str(device_props.minor)
-    except:
+    except (RuntimeError, AssertionError):
         gpu_version = None
 
     prepare_plugins(cfg)

src/axolotl/convert.py

@@ -67,7 +67,7 @@ class JsonToJsonlConverter:
         self.json_parser = json_parser
         self.jsonl_serializer = jsonl_serializer
 
-    def convert(self, input_file_path, output_file_path):
+    def convert(self, input_file_path):
         content = self.file_reader.read(input_file_path)
         data = self.json_parser.parse(content)
         # data = [r for r in data if r["conversations"]]  # vicuna cleaned has rows with empty conversations

src/axolotl/utils/quantization.py

@@ -29,7 +29,7 @@ if version.parse(torch.__version__) >= version.parse("2.8.0"):
         from torchao.prototype.mx_formats import NVFP4InferenceConfig
 
         quantization_config_to_str[NVFP4InferenceConfig] = "nvfp4"
-    except:
+    except (ImportError, RuntimeError):
         pass
 
     # int4 weight config imports will fail on machines with fbgemm-gpu installed
@@ -38,7 +38,7 @@ if version.parse(torch.__version__) >= version.parse("2.8.0"):
         from torchao.quantization.quant_api import Int4WeightOnlyConfig
 
         quantization_config_to_str[Int4WeightOnlyConfig] = "int4"
-    except:
+    except (ImportError, RuntimeError):
         pass
 
     try:

tests/test_convert.py

@@ -0,0 +1,91 @@
+"""Unit tests for src/axolotl/convert.py"""
+
+import json
+
+import pytest
+
+from axolotl.convert import (
+    FileReader,
+    FileWriter,
+    JsonlSerializer,
+    JsonParser,
+    JsonToJsonlConverter,
+    StdoutWriter,
+)
+
+
+class TestJsonParser:
+    def test_parse_valid_json_array(self):
+        parser = JsonParser()
+        result = parser.parse('[{"key": "value"}]')
+        assert result == [{"key": "value"}]
+
+    def test_parse_valid_json_object(self):
+        parser = JsonParser()
+        result = parser.parse('{"key": "value"}')
+        assert result == {"key": "value"}
+
+    def test_parse_invalid_json_raises(self):
+        parser = JsonParser()
+        with pytest.raises(json.JSONDecodeError):
+            parser.parse("not valid json")
+
+
+class TestJsonlSerializer:
+    def test_serialize_single_item(self):
+        serializer = JsonlSerializer()
+        result = serializer.serialize([{"a": 1}])
+        assert result == '{"a": 1}'
+
+    def test_serialize_multiple_items(self):
+        serializer = JsonlSerializer()
+        result = serializer.serialize([{"a": 1}, {"b": 2}])
+        lines = result.split("\n")
+        assert len(lines) == 2
+        assert json.loads(lines[0]) == {"a": 1}
+        assert json.loads(lines[1]) == {"b": 2}
+
+    def test_serialize_empty_list(self):
+        serializer = JsonlSerializer()
+        result = serializer.serialize([])
+        assert result == ""
+
+
+class TestFileReaderWriter:
+    def test_read_write_roundtrip(self, tmp_path):
+        test_file = tmp_path / "test.txt"
+        content = '{"hello": "world"}'
+        writer = FileWriter(str(test_file))
+        writer.write(content)
+
+        reader = FileReader()
+        result = reader.read(str(test_file))
+        assert result == content
+
+
+class TestStdoutWriter:
+    def test_write_to_stdout(self, capsys):
+        writer = StdoutWriter()
+        writer.write("hello")
+        captured = capsys.readouterr()
+        assert captured.out == "hello\n"
+
+
+class TestJsonToJsonlConverter:
+    def test_convert_json_to_jsonl(self, tmp_path):
+        input_data = [{"name": "Alice"}, {"name": "Bob"}]
+        input_file = tmp_path / "input.json"
+        output_file = tmp_path / "output.jsonl"
+
+        input_file.write_text(json.dumps(input_data), encoding="utf-8")
+
+        converter = JsonToJsonlConverter(
+            FileReader(), FileWriter(str(output_file)), JsonParser(), JsonlSerializer()
+        )
+        converter.convert(str(input_file))
+
+        result = output_file.read_text(encoding="utf-8")
+        lines = result.split("\n")
+        assert len(lines) == 2
+        assert json.loads(lines[0]) == {"name": "Alice"}
+        assert json.loads(lines[1]) == {"name": "Bob"}