Correctly format files and ranges with line endings other than LF

.github/workflows/python.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9, "3.10"]
+        python-version: [3.7, 3.8, 3.9, "3.10"]
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}

pylsp_black/plugin.py

@@ -6,9 +6,11 @@
 import black
 import toml
 from pylsp import hookimpl
+from pylsp._utils import get_eol_chars
 
 logger = logging.getLogger(__name__)
 
+
 GLOBAL_CONFIG: Optional[Path] = None
 try:
     if os.name == "nt":
@@ -68,8 +70,25 @@ def format_text(*, text, config):
         string_normalization=not config["skip_string_normalization"],
     )
     try:
-        # will raise black.NothingChanged, we want to bubble that exception up
-        return black.format_file_contents(text, fast=config["fast"], mode=mode)
+        # Black's format_file_contents only works reliably when eols are '\n'. It gives
+        # an error for '\r' and produces wrong formatting for '\r\n'. So we replace
+        # those eols by '\n' before formatting and restore them afterwards.
+        replace_eols = False
+        eol_chars = get_eol_chars(text)
+        if eol_chars is not None and eol_chars != "\n":
+            replace_eols = True
+            text = text.replace(eol_chars, "\n")
+
+        # Will raise black.NothingChanged, we want to bubble that exception up
+        formatted_text = black.format_file_contents(
+            text, fast=config["fast"], mode=mode
+        )
+
+        # Restore eols if necessary.
+        if replace_eols:
+            formatted_text = formatted_text.replace("\n", eol_chars)
+
+        return formatted_text
     except (
         # raised when the file has syntax errors
         ValueError,

setup.cfg

@@ -18,8 +18,8 @@ classifiers =
 
 [options]
 packages = find:
-install_requires = python-lsp-server; black>=19.3b0; toml
-python_requires = >= 3.6
+install_requires = python-lsp-server>=1.4.0; black>=19.3b0; toml
+python_requires = >= 3.7
 
 [options.entry_points]
 pylsp = pylsp_black = pylsp_black.plugin

tests/fixtures/formatted-crlf.py

@@ -0,0 +1,4 @@
+if True:
+    print("foo")
+
+print("bar")  # noqa

tests/fixtures/unformatted-crlf.py

@@ -0,0 +1,4 @@
+if True:
+    print("foo")
+
+print("bar")  # noqa

tests/test_plugin.py

@@ -39,6 +39,15 @@ def unformatted_pyi_document(workspace):
     return Document(uri, workspace)
 
 
+@pytest.fixture
+def unformatted_crlf_document(workspace):
+    path = fixtures_dir / "unformatted-crlf.py"
+    uri = f"file:/{path}"
+    with open(path, "r", newline="") as f:
+        source = f.read()
+    return Document(uri, workspace, source=source)
+
+
 @pytest.fixture
 def formatted_document(workspace):
     path = fixtures_dir / "formatted.txt"
@@ -53,6 +62,15 @@ def formatted_pyi_document(workspace):
     return Document(uri, workspace)
 
 
+@pytest.fixture
+def formatted_crlf_document(workspace):
+    path = fixtures_dir / "formatted-crlf.py"
+    uri = f"file:/{path}"
+    with open(path, "r", newline="") as f:
+        source = f.read()
+    return Document(uri, workspace, source=source)
+
+
 @pytest.fixture
 def invalid_document(workspace):
     path = fixtures_dir / "invalid.txt"
@@ -225,3 +243,17 @@ def test_entry_point():
 
     module = entry_point.load()
     assert isinstance(module, types.ModuleType)
+
+
+def test_pylsp_format_crlf_document(unformatted_crlf_document, formatted_crlf_document):
+    result = pylsp_format_document(unformatted_crlf_document)
+
+    assert result == [
+        {
+            "range": {
+                "start": {"line": 0, "character": 0},
+                "end": {"line": 4, "character": 0},
+            },
+            "newText": formatted_crlf_document.source,
+        }
+    ]