Carefully parse warning messages when building documentation (apache#8693)

Author: mik-laj

docs/build

@@ -272,11 +272,19 @@ def parse_sphinx_warnings(warning_text: str) -> List[DocBuildError]:
             continue
         warning_parts = sphinx_warning.split(":", 2)
         if len(warning_parts) == 3:
-            sphinx_build_errors.append(
-                DocBuildError(
-                    file_path=warning_parts[0], line_no=int(warning_parts[1]), message=warning_parts[2]
+            try:
+                sphinx_build_errors.append(
+                    DocBuildError(
+                        file_path=warning_parts[0], line_no=int(warning_parts[1]), message=warning_parts[2]
+                    )
+                )
+            except Exception:  # pylint: disable=broad-except
+                # If an exception occurred while parsing the warning message, display the raw warning message.
+                sphinx_build_errors.append(
+                    DocBuildError(
+                        file_path=None, line_no=None, message=sphinx_warning
+                    )
                 )
-            )
         else:
             sphinx_build_errors.append(DocBuildError(file_path=None, line_no=None, message=sphinx_warning))
     return sphinx_build_errors