Merge pull request #182 from filippog/cli-dry-run

CLI --check / dry-run mode

src/yamlfix/entrypoints/cli.py

@@ -1,6 +1,7 @@
 """Command line interface definition."""
 
 import logging
+import sys
 from typing import Tuple
 
 import click
@@ -20,17 +21,26 @@ def _format_file_list(files: Tuple[TextIOWrapper]) -> str:
 @click.command()
 @click.version_option(version="", message=version.version_info())
 @click.option("--verbose", is_flag=True, help="Enable verbose logging.")
+@click.option(
+    "--check",
+    is_flag=True,
+    help="Check if file(s) needs fixing. No files will be written in this case.",
+)
 @click.argument("files", type=click.File("r+"), required=True, nargs=-1)
-def cli(files: Tuple[str], verbose: bool) -> None:
+def cli(files: Tuple[str], verbose: bool, check: bool) -> None:
     """Corrects the source code of the specified files."""
     load_logger(verbose)
-    log.info("Fixing files:%s", _format_file_list(files))
-    fixed_code = services.fix_files(files)
+    log.info("%s files:%s", "Checking" if check else "Fixing", _format_file_list(files))
+
+    fixed_code, changed = services.fix_files(files, check)
 
     if fixed_code is not None:
         print(fixed_code, end="")
     log.info("Done.")
 
+    if changed and check:
+        sys.exit(1)
+
 
 if __name__ == "__main__":  # pragma: no cover
     cli()  # pylint: disable=E1120

src/yamlfix/services.py

@@ -6,8 +6,9 @@
 
 import logging
 import re
+import warnings
 from io import StringIO
-from typing import List, Optional, Tuple, Union
+from typing import List, Optional, Tuple, Union, overload
 
 import ruyaml
 from _io import TextIOWrapper
@@ -17,17 +18,47 @@
 Files = Union[Tuple[TextIOWrapper], List[str]]
 
 
+@overload
 def fix_files(files: Files) -> Optional[str]:
+    ...
+
+
+@overload
+def fix_files(files: Files, dry_run: Optional[bool]) -> Tuple[Optional[str], bool]:
+    ...
+
+
+def fix_files(  # pylint: disable=too-many-branches
+    files: Files, dry_run: Optional[bool] = None
+) -> Union[Optional[str], Tuple[Optional[str], bool]]:  # noqa: TAE002
     """Fix the yaml source code of a list of files.
 
     If the input is taken from stdin, it will return the fixed value.
 
     Args:
         files: List of files to fix.
+        dry_run: Whether to write changes or not.
 
     Returns:
-        Fixed code retrieved from stdin or None.
+        A tuple with the following items:
+        * Fixed code or None.
+        * A bool to indicate whether at least one file has been changed.
     """
+    changed = False
+
+    if dry_run is None:
+        warnings.warn(
+            """
+            From 2023-01-12 fix_files will change the return type from
+            `Optional[str]` to Tuple[Optional[str], bool], where the first
+            element of the Tuple is the fixed source and the second a bool that
+            returns whether the source has changed.
+
+            For more information check https://github.com/lyz-code/yamlfix/pull/182
+            """,
+            UserWarning,
+        )
+
     for file_ in files:
         if isinstance(file_, str):
             with open(file_, "r", encoding="utf-8") as file_descriptor:
@@ -40,10 +71,18 @@ def fix_files(files: Files) -> Optional[str]:
         log.debug("Fixing file %s...", file_name)
         fixed_source = fix_code(source)
 
+        if fixed_source != source:
+            changed = True
+
         if file_name == "<stdin>":
-            return fixed_source
+            if dry_run is None:
+                return fixed_source
+            return (fixed_source, changed)
 
         if fixed_source != source:
+            if dry_run:
+                log.debug("Need to fix file %s.", file_name)
+                continue
             if isinstance(file_, str):
                 with open(file_, "w", encoding="utf-8") as file_descriptor:
                     file_descriptor.write(fixed_source)
@@ -55,7 +94,10 @@ def fix_files(files: Files) -> Optional[str]:
         else:
             log.debug("Left file %s unmodified.", file_name)
 
-    return None
+    if dry_run is None:
+        return None
+
+    return (None, changed)
 
 
 def fix_code(source_code: str) -> str:

tests/e2e/test_cli.py

@@ -124,3 +124,34 @@ def test_ignores_correct_files(
         logging.DEBUG,
         f"Left file {test_file} unmodified.",
     ) in caplog.record_tuples
+
+
+def test_check_one_file_changes(runner: CliRunner, tmpdir: LocalPath) -> None:
+    """The --check flag is working with fixes to do."""
+    # ignore: call to untyped join method, they don't have type hints
+    test_file_source = "program: yamlfix"
+    test_file = tmpdir.join("source.yaml")  # type: ignore
+    test_file.write(test_file_source)
+
+    result = runner.invoke(cli, [str(test_file), "--check"])
+
+    assert result.exit_code == 1
+    assert test_file.read() == test_file_source
+
+
+def test_check_one_file_no_changes(runner: CliRunner, tmpdir: LocalPath) -> None:
+    """The --check flag is working with pending changes."""
+    # ignore: call to untyped join method, they don't have type hints
+    test_file_source = dedent(
+        """\
+        ---
+        program: yamlfix
+        """
+    )
+    test_file = tmpdir.join("source.yaml")  # type: ignore
+    test_file.write(test_file_source)
+
+    result = runner.invoke(cli, [str(test_file), "--check"])
+
+    assert result.exit_code == 0
+    assert test_file.read() == test_file_source

tests/unit/test_services.py

@@ -52,10 +52,22 @@ def test_fix_files_can_process_string_arguments(self, tmpdir: LocalPath) -> None
             """
         )
 
-        fix_files([str(test_file)])  # act
+        fix_files([str(test_file)], False)  # act
 
         assert test_file.read() == fixed_source
 
+    def test_fix_files_issues_warning(self, tmpdir: LocalPath) -> None:
+        """
+        Given: A file to fix
+        When: Using the old signature
+        Then: A warning is issued
+        """
+        test_file = tmpdir.join("source.yaml")  # type: ignore
+        test_file.write("program: yamlfix")
+        with pytest.warns(UserWarning, match="yamlfix/pull/182"):
+
+            fix_files([str(test_file)])  # act
+
 
 class TestFixCode:
     """Test the fix_code function."""