Improve EDTFParseException handling

Includes handling for empty or null input strings and null errs passed to the constructor

Co-Authored-By: aweakley <224316+aweakley@users.noreply.github.com>

Author: ColeDCrawford

edtf/fields.py

@@ -4,10 +4,12 @@
 from django.db import models
 from django.db.models import signals
 from django.db.models.query_utils import DeferredAttribute
+from pyparsing import ParseException
 
 from edtf import EDTFObject, parse_edtf
 from edtf.convert import struct_time_to_date, struct_time_to_jd
 from edtf.natlang import text_to_edtf
+from edtf.parser.edtf_exceptions import EDTFParseException
 
 DATE_ATTRS = (
     "lower_strict",
@@ -132,10 +134,12 @@ def update_values(self, instance, *args, **kwargs):
         if direct_input and (
             existing_value is None or str(existing_value) != direct_input
         ):
-            edtf = parse_edtf(
-                direct_input, fail_silently=True
-            )  # ParseException if invalid; should this be raised?
-            # TODO pyparsing.ParseExceptions are very noisy and dumps the whole grammar (see https://github.com/ixc/python-edtf/issues/46)
+            try:
+                edtf = parse_edtf(
+                    direct_input, fail_silently=True
+                )  # ParseException if invalid; should this be raised?
+            except ParseException as err:
+                raise EDTFParseException(direct_input, err) from None
 
             # set the natural_text (display) field to the direct_input if it is not provided
             if natural_text == "":

edtf/parser/edtf_exceptions.py

@@ -2,4 +2,28 @@
 
 
 class EDTFParseException(ParseException):
-    pass
+    """Raised when an input cannot be parsed as an EDTF string.
+
+    Attributes:
+    input_string - the input string that could not be parsed
+    err -- the original ParseException that caused this one
+    """
+
+    def __init__(self, input_string, err=None):
+        if input_string is None:
+            input_string = ""
+        self.input_string = input_string
+        if err is None:
+            err = ParseException(input_string, 0, "Invalid input or format.")
+        self.err = err
+        super().__init__(str(err), err.loc if err.loc else 0, self.input_string)
+
+    def __str__(self):
+        if not self.input_string:
+            return "You must supply some input text"
+        near_text = (
+            self.input_string[max(self.err.loc - 10, 0) : self.err.loc + 10]
+            if hasattr(self.err, "loc")
+            else ""
+        )
+        return f"Error at position {self.err.loc}: Invalid input or format near '{near_text}'. Please provide a valid EDTF string."

edtf/parser/grammar.py

@@ -347,7 +347,7 @@ def parse_edtf(input_string, parseAll=True, fail_silently=False, debug=None):
     if debug is None:
         debug = DEBUG_PYPARSING
     if not input_string:
-        raise EDTFParseException("You must supply some input text")
+        raise EDTFParseException(input_string)
     try:
         p = edtfParser.parseString(input_string.strip(), parseAll)
         if p:
@@ -357,8 +357,4 @@ def parse_edtf(input_string, parseAll=True, fail_silently=False, debug=None):
             return None
         if debug:
             raise
-        near_text = ""
-        if input_string:
-            near_text = input_string[max(err.loc - 10, 0) : err.loc + 10]
-        full_msg = f"Error at position {err.loc}: Invalid input or format near '{near_text}'. Please provide a valid EDTF string."
-        raise EDTFParseException(full_msg) from None
+        raise EDTFParseException(input_string, err) from None