Merge pull request #22 from haplo/log-errors

Log black errors to stderr

pylsp_black/plugin.py

@@ -1,9 +1,12 @@
+import logging
 from typing import Dict
 
 import black
 import toml
 from pylsp import hookimpl
 
+logger = logging.getLogger(__name__)
+
 
 @hookimpl(tryfirst=True)
 def pylsp_format_document(document):
@@ -34,16 +37,8 @@ def format_document(document, range=None):
 
     try:
         formatted_text = format_text(text=text, config=config)
-    except (
-        ValueError,
+    except black.NothingChanged:
         # raised when the file is already formatted correctly
-        black.NothingChanged,
-        # raised when the file being formatted has an indentation error
-        IndentationError,
-        # raised when black produces invalid Python code or formats the file
-        # differently on the second pass
-        AssertionError,
-    ):
         return []
 
     return [{"range": range, "newText": formatted_text}]
@@ -56,8 +51,21 @@ def format_text(*, text, config):
         is_pyi=config["pyi"],
         string_normalization=not config["skip_string_normalization"],
     )
-
-    return black.format_file_contents(text, fast=config["fast"], mode=mode)
+    try:
+        # will raise black.NothingChanged, we want to bubble that exception up
+        return black.format_file_contents(text, fast=config["fast"], mode=mode)
+    except (
+        # raised when the file has syntax errors
+        ValueError,
+        # raised when the file being formatted has an indentation error
+        IndentationError,
+        # raised when black produces invalid Python code or formats the file
+        # differently on the second pass
+        AssertionError,
+    ) as e:
+        # errors will show on lsp stderr stream
+        logger.error("Error formatting with black: %s", e)
+        raise black.NothingChanged from e
 
 
 def load_config(filename: str) -> Dict:
@@ -74,11 +82,16 @@ def load_config(filename: str) -> Dict:
     pyproject_filename = root / "pyproject.toml"
 
     if not pyproject_filename.is_file():
+        logger.info("Using defaults: %r", defaults)
         return defaults
 
     try:
         pyproject_toml = toml.load(str(pyproject_filename))
     except (toml.TomlDecodeError, OSError):
+        logger.warning(
+            "Error decoding pyproject.toml, using defaults: %r",
+            defaults,
+        )
         return defaults
 
     file_config = pyproject_toml.get("tool", {}).get("black", {})
@@ -108,4 +121,6 @@ def load_config(filename: str) -> Dict:
 
     config["target_version"] = target_version
 
+    logger.info("Using config from %s: %r", pyproject_filename, config)
+
     return config