1 files changed, 64 insertions, 0 deletions
diff --git a/third_party/python/mozilla-version/mozilla_version/errors.py b/third_party/python/mozilla-version/mozilla_version/errors.py
new file mode 100644
index 0000000000..84cd2169f5
--- /dev/null
+++ b/third_party/python/mozilla-version/mozilla_version/errors.py
@@ -0,0 +1,64 @@
+"""Defines all errors reported by mozilla-version."""
+
+
+class PatternNotMatchedError(ValueError):
+    """Error when a string doesn't match an expected pattern.
+
+    Args:
+        string (str): The string it was unable to match.
+        pattern (str): The pattern used it tried to match.
+    """
+
+    def __init__(self, string, pattern):
+        """Constructor."""
+        super(PatternNotMatchedError, self).__init__(
+            '"{}" does not match the pattern: {}'.format(string, pattern)
+        )
+
+
+class NoVersionTypeError(ValueError):
+    """Error when `version_string` matched the pattern, but was unable to find its type.
+
+    Args:
+        version_string (str): The string it was unable to guess the type.
+    """
+
+    def __init__(self, version_string):
+        """Constructor."""
+        super(NoVersionTypeError, self).__init__(
+            'Version "{}" matched the pattern of a valid version, but it is unable to find what type it is. \
+This is likely a bug in mozilla-version'.format(version_string)
+        )
+
+
+class MissingFieldError(ValueError):
+    """Error when `version_string` lacks an expected field.
+
+    Args:
+        version_string (str): The string it was unable to extract a given field.
+        field_name (str): The name of the missing field.
+    """
+
+    def __init__(self, version_string, field_name):
+        """Constructor."""
+        super(MissingFieldError, self).__init__(
+            'Release "{}" does not contain a valid {}'.format(version_string, field_name)
+        )
+
+
+class TooManyTypesError(ValueError):
+    """Error when `version_string` has too many types."""
+
+    def __init__(self, version_string, first_matched_type, second_matched_type):
+        """Constructor.
+
+        Args:
+            version_string (str): The string that gave too many types.
+            first_matched_type (str): The name of the first detected type.
+            second_matched_type (str): The name of the second detected type
+        """
+        super(TooManyTypesError, self).__init__(
+            'Release "{}" cannot match types "{}" and "{}"'.format(
+                version_string, first_matched_type, second_matched_type
+            )
+        )