Handle missing run styles in the source document

2 files changed, 31 insertions, 16 deletions

diff --git a/mammoth/docx/body_xml.py b/mammoth/docx/body_xml.py
index 854ccf2..ae33191 100644
--- a/mammoth/docx/body_xml.py
+++ b/mammoth/docx/body_xml.py
@@ -67,6 +67,7 @@ def _create_reader(numbering, content_types, relationships, styles, docx_file, f
 
 
     def run(element):
+        messages = []
         properties = element.find_child_or_null("w:rPr")
         style_id = properties \
             .find_child_or_null("w:rStyle") \
@@ -75,7 +76,12 @@ def _create_reader(numbering, content_types, relationships, styles, docx_file, f
         if style_id is None:
             style_name = None
         else:
-            style_name = styles.find_character_style_by_id(style_id).name
+            style = styles.find_character_style_by_id(style_id)
+            if style is None:
+                style_name = None
+                messages.append(_undefined_style_warning("Run", style_id))
+            else:
+                style_name = style.name
         
         vertical_alignment = properties \
             .find_child_or_null("w:vertAlign") \
@@ -87,16 +93,18 @@ def _create_reader(numbering, content_types, relationships, styles, docx_file, f
         is_strikethrough = properties.find_child("w:strike")
         
         return _read_xml_elements(element.children) \
-            .map(lambda children: documents.run(
-                children=children,
-                style_id=style_id,
-                style_name=style_name,
-                is_bold=is_bold,
-                is_italic=is_italic,
-                is_underline=is_underline,
-                is_strikethrough=is_strikethrough,
-                vertical_alignment=vertical_alignment,
-            ))
+            .bind(lambda children: _element_result_with_messages(
+                documents.run(
+                    children=children,
+                    style_id=style_id,
+                    style_name=style_name,
+                    is_bold=is_bold,
+                    is_italic=is_italic,
+                    is_underline=is_underline,
+                    is_strikethrough=is_strikethrough,
+                    vertical_alignment=vertical_alignment,
+                ),
+                messages))
 
 
     def paragraph(element):
diff --git a/tests/docx/body_xml_tests.py b/tests/docx/body_xml_tests.py
index a3a7802..2d6644c 100644
--- a/tests/docx/body_xml_tests.py
+++ b/tests/docx/body_xml_tests.py
@@ -116,22 +116,29 @@ class ReadXmlElementTests(object):
         assert_equal(None, _read_and_get_document_xml_element(element).style_id)
         
     @istest
-    def run_has_style_id_read_from_run_properties_if_present(self):
+    def run_has_style_id_and_name_read_from_run_properties_if_present(self):
         style_xml = xml_element("w:rStyle", {"w:val": "Heading1Char"})
         
         styles = Styles({}, {"Heading1Char": Style(style_id="Heading1Char", name="Heading 1 Char")})
         
         run = self._read_run_with_properties([style_xml], styles=styles)
         assert_equal("Heading1Char", run.style_id)
+        assert_equal("Heading 1 Char", run.style_name)
         
     @istest
-    def run_has_style_name_read_from_run_properties_and_styles(self):
+    def warning_is_emitted_when_run_style_cannot_be_found(self):
         style_xml = xml_element("w:rStyle", {"w:val": "Heading1Char"})
+        properties_xml = xml_element("w:rPr", {}, [style_xml])
+        run_xml = xml_element("w:r", {}, [properties_xml])
         
-        styles = Styles({}, {"Heading1Char": Style(style_id="Heading1Char", name="Heading 1 Char")})
+        styles = Styles({}, {})
+        
+        result = _read_document_xml_element(run_xml, styles=styles)
+        run = result.value
+        assert_equal("Heading1Char", run.style_id)
+        assert_equal(None, run.style_name)
+        assert_equal([results.warning("Run style with ID Heading1Char was referenced but not defined in the document")], result.messages)
         
-        run = self._read_run_with_properties([style_xml], styles=styles)
-        assert_equal("Heading 1 Char", run.style_name)
         
     @istest
     def run_is_not_bold_if_bold_element_is_not_present(self):