feat: add support for global config flag

src/sqlfmt/cli.py

@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import List, Union
+from typing import List, Optional, Union
 
 import click
 
@@ -152,14 +152,29 @@
         "case sensitivity in function, field, and alias names."
     ),
 )
+@click.option(
+    "--config",
+    "config_path",
+    envvar="SQLFMT_CONFIG",
+    type=click.Path(
+        exists=True, dir_okay=False, allow_dash=False, resolve_path=True, path_type=Path
+    ),
+    help=(
+        "A path to a `pyproject.toml` file. Options passed at the command line will "
+        "override settings in this file."
+    ),
+)
 @click.argument(
     "files",
     nargs=-1,
     type=click.Path(exists=True, allow_dash=True, resolve_path=True, path_type=Path),
 )
 @click.pass_context
 def sqlfmt(
-    ctx: click.Context, files: List[Path], **kwargs: Union[bool, int, List[str], str]
+    ctx: click.Context,
+    files: List[Path],
+    config_path: Optional[Path] = None,
+    **kwargs: Union[bool, int, List[str], str],
 ) -> None:
     """
     sqlfmt formats your dbt SQL files so you don't have to.
@@ -173,7 +188,7 @@ def sqlfmt(
     https://sqlfmt.com for documentation and more information.
     """
     if files:
-        config = load_config_file(files)
+        config = load_config_file(files, config_path)
         non_default_options = {
             k: v
             for k, v in kwargs.items()

src/sqlfmt/config.py

@@ -15,14 +15,19 @@
 Config = Dict[str, Union[bool, int, List[str], str, Path]]
 
 
-def load_config_file(files: List[Path]) -> Config:
+def load_config_file(files: List[Path], config_path: Optional[Path]) -> Config:
     """
     files is a list of resolved, absolute paths (like the ones passed from the
     Click CLI). This finds a pyproject.toml file in the common parent directory
     of files (or in the common parent's parents).
+
+    If config_path is provided, searching for a config via files will be skipped
+    entirely.
     """
-    common_parents = _get_common_parents(files)
-    config_path = _find_config_file(common_parents)
+    if config_path is None:
+        common_parents = _get_common_parents(files)
+        config_path = _find_config_file(common_parents)
+
     config = _load_config_from_path(config_path)
     return config
 

tests/unit_tests/test_cli.py

@@ -209,3 +209,67 @@ def test_preformatted_inherit_encoding(
         assert results.stderr.startswith("1 file had errors")
         assert "006_has_bom.sql" in results.stderr
         assert "Could not parse SQL at position 1" in results.stderr
+
+
+def test_config_option(sqlfmt_runner: CliRunner, preformatted_dir: Path) -> None:
+    copy_config_file_to_dst("valid_sqlfmt_config.toml", preformatted_dir)
+    args = (
+        f"{preformatted_dir.as_posix()} "
+        f"--config {(preformatted_dir / 'pyproject.toml').as_posix()} "
+        "--check"
+    )
+    results = sqlfmt_runner.invoke(sqlfmt_main, args=args)
+    # 3 files should fail formatting with longer line length in config
+    assert results.exit_code == 1
+    assert results.stderr.startswith("3 files failed formatting check")
+
+    args = f"{preformatted_dir.as_posix()} --check"
+    results = sqlfmt_runner.invoke(
+        sqlfmt_main,
+        args=args,
+        env={"SQLFMT_CONFIG": f"{preformatted_dir.as_posix()}/pyproject.toml"},
+    )
+    assert results.exit_code == 1
+    assert results.stderr.startswith("3 files failed formatting check")
+
+    # supply CLI args to override config file so checks pass
+    args = (
+        f"{preformatted_dir.as_posix()} "
+        f"--config {(preformatted_dir / 'pyproject.toml').as_posix()} "
+        "--line-length 88 --check"
+    )
+    results = sqlfmt_runner.invoke(sqlfmt_main, args=args)
+    assert results.exit_code == 0
+
+    # supply CLI args to override config file so checks pass
+    args = f"{preformatted_dir.as_posix()} --line-length 88 --check"
+    results = sqlfmt_runner.invoke(
+        sqlfmt_main,
+        args=args,
+        env={"SQLFMT_CONFIG": f"{preformatted_dir.as_posix()}/pyproject.toml"},
+    )
+    assert results.exit_code == 0
+
+
+def test_config_does_not_exist(
+    sqlfmt_runner: CliRunner, preformatted_dir: Path
+) -> None:
+    # make sure sqlfmt fails fast if the passed config doesn't exist
+    args = (
+        f"--config {preformatted_dir.as_posix()}/does_not_exist.toml "
+        f"{preformatted_dir.as_posix()}"
+    )
+    results = sqlfmt_runner.invoke(sqlfmt_main, args=args)
+    assert results.exit_code == 2
+    assert "Error: Invalid value for '--config'" in results.stderr
+    assert "does not exist" in results.stderr
+
+    args = f"{preformatted_dir.as_posix()}"
+    results = sqlfmt_runner.invoke(
+        sqlfmt_main,
+        args=args,
+        env={"SQLFMT_CONFIG": f"{preformatted_dir.as_posix()}/does_not_exist.toml"},
+    )
+    assert results.exit_code == 2
+    assert "Error: Invalid value for '--config'" in results.stderr
+    assert "does not exist" in results.stderr