1 files changed, 40 insertions, 0 deletions
diff --git a/third_party/python/voluptuous/voluptuous/humanize.py b/third_party/python/voluptuous/voluptuous/humanize.py
new file mode 100644
index 0000000000..91ab2015fb
--- /dev/null
+++ b/third_party/python/voluptuous/voluptuous/humanize.py
@@ -0,0 +1,40 @@
+from voluptuous import Invalid, MultipleInvalid
+from voluptuous.error import Error
+
+
+MAX_VALIDATION_ERROR_ITEM_LENGTH = 500
+
+
+def _nested_getitem(data, path):
+    for item_index in path:
+        try:
+            data = data[item_index]
+        except (KeyError, IndexError, TypeError):
+            # The index is not present in the dictionary, list or other
+            # indexable or data is not subscriptable
+            return None
+    return data
+
+
+def humanize_error(data, validation_error, max_sub_error_length=MAX_VALIDATION_ERROR_ITEM_LENGTH):
+    """ Provide a more helpful + complete validation error message than that provided automatically
+    Invalid and MultipleInvalid do not include the offending value in error messages,
+    and MultipleInvalid.__str__ only provides the first error.
+    """
+    if isinstance(validation_error, MultipleInvalid):
+        return '\n'.join(sorted(
+            humanize_error(data, sub_error, max_sub_error_length)
+            for sub_error in validation_error.errors
+        ))
+    else:
+        offending_item_summary = repr(_nested_getitem(data, validation_error.path))
+        if len(offending_item_summary) > max_sub_error_length:
+            offending_item_summary = offending_item_summary[:max_sub_error_length - 3] + '...'
+        return '%s. Got %s' % (validation_error, offending_item_summary)
+
+
+def validate_with_humanized_errors(data, schema, max_sub_error_length=MAX_VALIDATION_ERROR_ITEM_LENGTH):
+    try:
+        return schema(data)
+    except (Invalid, MultipleInvalid) as e:
+        raise Error(humanize_error(data, e, max_sub_error_length))