ScannerError: pass diagnostic information to ValidationMessage

* submission file validator: append ScannerError exception to message
* data file validator: catch ScannerError exception and add message
* README: explain how to print error messages
* release: version 0.1.11

Signed-off-by: Graeme Watt <graeme.watt@durham.ac.uk>

README.md

@@ -37,6 +37,9 @@ is_valid_submission_file = submission_file_validator.validate(file_path=submissi
 
 # if there are any error messages, they are retrievable through this call
 submission_file_validator.get_messages()
+
+# the error messages can be printed
+submission_file_validator.print_errors(submission_file_path)
 ```
 
 Data file validation is exactly the same.
@@ -51,6 +54,9 @@ data_file_validator.validate(file_path='data.yaml')
 
 # if there are any error messages, they are retrievable through this call
 data_file_validator.get_messages()
+
+# the error messages can be printed
+data_file_validator.print_errors('data.yaml')
 ```
 
 Optionally, if you have already loaded the YAML object, then you can pass it through

hepdata_validator/__init__.py

@@ -1,6 +1,7 @@
 import json
 from jsonschema import validate, ValidationError
 import yaml
+from yaml.scanner import ScannerError
 from yaml.parser import ParserError
 
 __author__ = 'eamonnmaguire'
@@ -33,9 +34,17 @@ def validate(self, **kwargs):
         if data is None:
 
             try:
-                data = yaml.load(open(file_path, 'r'), Loader=yaml.CLoader)
+                try:
+                    data = yaml.load(open(file_path, 'r'), Loader=yaml.CLoader)
+                except ScannerError as se:
+                    self.add_validation_message(ValidationMessage(file=file_path, message=str(se)))
+                    return False
             except: #pragma: no cover
-                data = yaml.load(open(file_path, 'r')) #pragma: no cover
+                try: #pragma: no cover
+                    data = yaml.load(open(file_path, 'r')) #pragma: no cover
+                except ScannerError as se: #pragma: no cover
+                    self.add_validation_message(ValidationMessage(file=file_path, message=str(se))) #pragma: no cover
+                    return False #pragma: no cover
 
         try:
             validate(data, schema)

hepdata_validator/submission_file_validator.py

@@ -65,7 +65,8 @@ def validate(self, **kwargs):
         except ScannerError as se:
             self.add_validation_message(
                     ValidationMessage(file=file_path,
-                                      message='There was a problem parsing the file. '
+                                      message='There was a problem parsing the file.  '
                                               'This can be because you forgot spaces '
-                                              'after colons in your YAML file for instance.')
+                                              'after colons in your YAML file for instance.  '
+                                              'Diagnostic information follows.\n' + str(se))
             )

setup.py

@@ -49,8 +49,8 @@ def run_tests(self):
 
 setup(
     name='hepdata_validator',
-    version='0.1.10',
-    summary='0.1.10 release',
+    version='0.1.11',
+    summary='0.1.11 release',
     url='https://github.com/hepdata/hepdata-validator',
     license='GPLv2',
     author='Eamonn Maguire',