give better error messages when failing to load file

nvchecker/__main__.py

@@ -33,14 +33,14 @@ def main() -> None:
   try:
     entries, options = core.load_file(
       args.file, use_keymanager=not bool(args.keyfile))
+
+    if args.keyfile:
+      keymanager = KeyManager(Path(args.keyfile))
+    else:
+      keymanager = options.keymanager
   except core.FileLoadError as e:
     sys.exit(str(e))
 
-  if args.keyfile:
-    keymanager = KeyManager(Path(args.keyfile))
-  else:
-    keymanager = options.keymanager
-
   if options.proxy is not None:
     ctx_proxy.set(options.proxy)
 

nvchecker/core.py

@@ -29,6 +29,7 @@ from . import slogconf
 from .util import (
   Entry, Entries, KeyManager, RawResult, Result, VersData,
   FunctionWorker, GetVersionError,
+  FileLoadError,
 )
 from . import __version__
 from .sortversion import sort_version_keys
@@ -149,22 +150,14 @@ class Options(NamedTuple):
   httplib: Optional[str]
   http_timeout: int
 
-class FileLoadError(Exception):
-  def __init__(self, kind, exc):
-    self.kind = kind
-    self.exc = exc
-
-  def __str__(self):
-    return f'failed to load {self.kind}: {self.exc}'
-
 def load_file(
   file: str, *,
   use_keymanager: bool,
 ) -> Tuple[Entries, Options]:
   try:
     config = toml.load(file)
-  except OSError as e:
-    raise FileLoadError('version configuration file', e)
+  except (OSError, toml.TomlDecodeError) as e:
+    raise FileLoadError('version configuration file', file, e)
 
   ver_files: Optional[Tuple[Path, Path]] = None
   keymanager = KeyManager(None)
@@ -189,10 +182,7 @@ def load_file(
         keyfile_s = os.path.expandvars(
           os.path.expanduser(c.get('keyfile')))
         keyfile = d / keyfile_s
-      try:
-        keymanager = KeyManager(keyfile)
-      except OSError as e:
-        raise FileLoadError('keyfile', e)
+      keymanager = KeyManager(keyfile)
 
     if 'source' in c:
       source_configs = c['source']

nvchecker/util.py

@@ -37,14 +37,26 @@ VersionResult.__doc__ = '''The result of a `get_version` check.
 * `Exception` - An error occurred.
 '''
 
+class FileLoadError(Exception):
+  def __init__(self, kind, filename, exc):
+    self.kind = kind
+    self.filename = filename
+    self.exc = exc
+
+  def __str__(self):
+    return f'failed to load {self.kind} {self.filename!r}: {self.exc}'
+
 class KeyManager:
   '''Manages data in the keyfile.'''
   def __init__(
     self, file: Optional[Path],
   ) -> None:
     if file is not None:
-      with file.open() as f:
-        keys = toml.load(f)['keys']
+      try:
+        with file.open() as f:
+          keys = toml.load(f)['keys']
+      except (OSError, toml.TomlDecodeError) as e:
+        raise FileLoadError('keyfile', str(file), e)
     else:
       keys = {}
     self.keys = keys