From 4009c626d4cb20c55580a156a0a7f422f61c2bfe Mon Sep 17 00:00:00 2001
From: Brett Smith <brettcsmith@brettcsmith.org>
Date: Mon, 29 Jul 2019 12:05:51 -0400
Subject: [PATCH] ledger_entry: Improve error reporting for amount expressions.

This is going to become more important as amount expressions become more
capable.
---
 import2ledger/hooks/ledger_entry.py | 16 +++++++++++-----
 tests/data/templates.ini            | 10 ++++++++++
 tests/test_hook_ledger_entry.py     |  9 +++++++++
 3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/import2ledger/hooks/ledger_entry.py b/import2ledger/hooks/ledger_entry.py
index d5a6d97..17ff7f2 100644
--- a/import2ledger/hooks/ledger_entry.py
+++ b/import2ledger/hooks/ledger_entry.py
@@ -168,11 +168,17 @@ class AccountSplitter:
     def _build_amounts(self, template_vars):
         amount_vars = {k: v for k, v in template_vars.items() if isinstance(v, decimal.Decimal)}
         amount_vars['Decimal'] = decimal.Decimal
-        amounts = [
-            (account, self._currency_decimal(eval(amount_expr, amount_vars),
-                                             template_vars['currency']))
-            for account, amount_expr in self.splits
-        ]
+        try:
+            amounts = [
+                (account, self._currency_decimal(eval(amount_expr, amount_vars),
+                                                 template_vars['currency']))
+                for account, amount_expr in self.splits
+            ]
+        except (ArithmeticError, NameError, TypeError, ValueError) as error:
+            raise errors.UserInputConfigurationError(
+                "{}: {}".format(type(error).__name__, error),
+                "template {!r}".format(self.template_name)
+            ) from error
         self._balance_amounts(amounts, template_vars['amount'])
         self._balance_amounts(amounts, -template_vars['amount'])
         return amounts
diff --git a/tests/data/templates.ini b/tests/data/templates.ini
index cf70544..5b8ce60 100644
--- a/tests/data/templates.ini
+++ b/tests/data/templates.ini
@@ -53,6 +53,16 @@ template =
  Expenses:Banking Fees  (6 if {amount} > 50 else 3)
  Income:Sales  -{amount}
 
+[NondecimalWord]
+template =
+ Income:Sales  -5
+ Assets:Cash   foo
+
+[NondecimalVariable]
+template =
+ Income:Sales  -5
+ Assets:Cash   {payee}
+
 [Empty]
 template =
 
diff --git a/tests/test_hook_ledger_entry.py b/tests/test_hook_ledger_entry.py
index fd23392..ffa7235 100644
--- a/tests/test_hook_ledger_entry.py
+++ b/tests/test_hook_ledger_entry.py
@@ -259,3 +259,12 @@ def test_hook_handles_template_undefined():
     entry_data = template_vars('DD', 1)
     assert not run_hook(entry_data, 'Nonexistent')
 
+def test_string_value_is_user_error():
+    entry_data = template_vars('EE', 1)
+    with pytest.raises(errors.UserInputConfigurationError):
+        run_hook(entry_data, 'NondecimalWord')
+
+def test_string_variable_is_user_error():
+    entry_data = template_vars('FF', 1)
+    with pytest.raises(errors.UserInputConfigurationError):
+        run_hook(entry_data, 'NondecimalVariable')