Adds an error message if the form indentation is wrong

HISTORY.rst

@@ -4,6 +4,9 @@ Changelog
 Unreleased
 ~~~~~~~~~~
 
+- Adds an error message if the form indentation is wrong.
+  [href]
+
 - Adds an error message for duplicate labels.
   [href]
 

onegov/form/parser/core.py

@@ -627,30 +627,39 @@ def translate_to_yaml(text):
     """
 
     lines = ((ix, l) for ix, l in prepare(text))
+    expect_nested = False
 
     for ix, line in lines:
 
+        indent = ' ' * (4 + (len(line) - len(line.lstrip())))
+
         # the top level are the fieldsets
         if match(elements.fieldset_title, line):
             yield '- "{}":'.format(line.lstrip('# ').rstrip())
+            expect_nested = False
             continue
 
         # fields are nested lists of dictionaries
         parse_result = try_parse(elements.single_line_fields, line)
         if parse_result is not None:
             yield '{indent}- "{identifier}": !{type} "{definition}"'.format(
-                indent=' ' * (4 + (len(line) - len(line.lstrip()))),
+                indent=indent,
                 type=parse_result.type,
                 identifier=line.split('=')[0].strip(),
                 definition=line.split('=')[1].strip()
             )
+            expect_nested = indent and True or False
             continue
 
         # checkboxes/radios come without identifier
         parse_result = try_parse(elements.boxes, line)
         if parse_result is not None:
+
+            if not expect_nested:
+                raise errors.InvalidFormSyntax(line=ix + 1)
+
             yield '{indent}- !{type} "{definition}":'.format(
-                indent=' ' * (4 + (len(line) - len(line.lstrip()))),
+                indent=indent,
                 type=parse_result.type,
                 definition=line.strip()
             )
@@ -664,9 +673,11 @@ def translate_to_yaml(text):
                 raise errors.InvalidFormSyntax(line=ix + 1)
 
             yield '{indent}- "{identifier}":'.format(
-                indent=' ' * (4 + (len(line) - len(line.lstrip()))),
+                indent=indent,
                 identifier=line.strip()
             )
+
+            expect_nested = True
             continue
 
         raise errors.InvalidFormSyntax(line=ix + 1)

onegov/form/tests/test_parser.py

@@ -387,3 +387,11 @@ def test_invalid_syntax():
             "Last Name * __"
         )))
     assert e.value.line == 4
+
+    with pytest.raises(errors.InvalidFormSyntax) as e:
+        parse_form('\n'.join((
+            "# Fields",
+            "",
+            "    [x] What",
+        )))
+    assert e.value.line == 3