Make validation errors more elegant

spacy/cli/_util.py

@@ -5,6 +5,10 @@ import srsly
 import hashlib
 import typer
 from typer.main import get_command
+from contextlib import contextmanager
+from thinc.config import ConfigValidationError
+from configparser import InterpolationError
+import sys
 
 from ..schemas import ProjectConfigSchema, validate
 
@@ -154,3 +158,17 @@ def get_checksum(path: Union[Path, str]) -> str:
             dir_checksum.update(sub_file.read_bytes())
         return dir_checksum.hexdigest()
     raise ValueError(f"Can't get checksum for {path}: not a file or directory")
+
+
+@contextmanager
+def show_validation_error(title: str = "Config validation error"):
+    """Helper to show custom config validation errors on the CLI.
+
+    title (str): Title of the custom formatted error.
+    """
+    try:
+        yield
+    except (ConfigValidationError, InterpolationError) as e:
+        msg.fail(title, spaced=True)
+        print(str(e).replace("Config validation error", "").strip())
+        sys.exit(1)

spacy/cli/train.py

@@ -6,13 +6,11 @@ from pathlib import Path
 from wasabi import msg
 import thinc
 import thinc.schedules
-from thinc.config import ConfigValidationError
 from thinc.api import use_pytorch_for_gpu_memory, require_gpu, fix_random_seed
 import random
 import typer
-import sys
 
-from ._util import app, Arg, Opt, parse_config_overrides
+from ._util import app, Arg, Opt, parse_config_overrides, show_validation_error
 from ..gold import Corpus, Example
 from ..lookups import Lookups
 from .. import util
@@ -83,17 +81,13 @@ def train(
 ) -> None:
     msg.info(f"Loading config from: {config_path}")
     # Read the config first without creating objects, to get to the original nlp_config
-    try:
+    with show_validation_error():
         config = util.load_config(
             config_path,
             create_objects=False,
             schema=ConfigSchema,
             overrides=config_overrides,
         )
-    except ConfigValidationError as e:
-        msg.fail("Config validation error")
-        print(str(e).replace("Config validation error", "").strip())
-        sys.exit(1)
     use_gpu = config["training"]["use_gpu"]
     if use_gpu >= 0:
         msg.info(f"Using GPU: {use_gpu}")