Fix escaped Jinja delimiters split across Word runs

docxtpl/template.py

@@ -87,6 +87,15 @@ def patch_xml(self, src_xml):
         strip all unnecessary xml tags, manage table cell background color and colspan,
         unescape html entities, etc..."""
 
+        # Join escaped Jinja delimiters that Word has split across runs. Limit the
+        # removable XML to tags inside one paragraph so unrelated text is untouched.
+        split_run_gap = (
+            r"(?:</w:t>(?:(?!</?w:p(?:\s|>))<[^>]+>)*<w:t(?: [^>]*)?>)?"
+        )
+        for escaped_delimiter in ("{_{", "}_}", "{_%", "%_}"):
+            pattern = split_run_gap.join(map(re.escape, escaped_delimiter))
+            src_xml = re.sub(pattern, escaped_delimiter, src_xml)
+
         # replace {<something>{ by {{   ( works with {{ }} {% and %} {# and #})
         src_xml = re.sub(
             r"(?<={)(<[^>]*>)+(?=[\{%\#])|(?<=[%\}\#])(<[^>]*>)+(?=\})",

tests/escaping_delimiters.py

@@ -0,0 +1,43 @@
+from pathlib import Path
+
+from docx import Document
+from docxtpl import DocxTemplate
+
+
+output_dir = Path(__file__).parent / "output"
+output_dir.mkdir(exist_ok=True)
+template_path = output_dir / "escaping_delimiters_split_tpl.docx"
+result_path = output_dir / "escaping_delimiters_split.docx"
+
+escaped_delimiters = ("{_%", "%_}", "{_{", "}_}")
+expected_delimiters = ("{%", "%}", "{{", "}}")
+
+template = Document()
+
+for delimiter in escaped_delimiters:
+    template.add_paragraph(delimiter)
+
+template.add_paragraph()
+
+for delimiter in escaped_delimiters:
+    paragraph = template.add_paragraph()
+    for character in delimiter:
+        paragraph.add_run(character)
+
+# These are not escaped delimiters and must not be changed.
+template.add_paragraph("{a_{hello")
+template.add_paragraph("{f_{")
+template.save(template_path)
+
+doc = DocxTemplate(template_path)
+doc.render({})
+doc.save(result_path)
+
+paragraphs = [paragraph.text for paragraph in Document(result_path).paragraphs]
+assert paragraphs == [
+    *expected_delimiters,
+    "",
+    *expected_delimiters,
+    "{a_{hello",
+    "{f_{",
+]