sphinx/conf.py: Filter out httdomain related warning since sphinx 4.1

Since the release of sphinx 4.1, a new warning related to httpdomain
extension appeared when buidling swh-web documentation.

It is not critical and is due to httpdomain not in sync with latest
changes in sphinx, so filter out that warning as it makes sphinx
builds fail for swh-web on Jenkins.

swh/docs/sphinx/conf.py

@@ -277,7 +277,7 @@ def setup(app):
         # ensure glossary will be available in package doc scope
         app.connect("source-read", add_glossary_to_index)
 
-        # suppress httpdomain warnings in non web packages
+        # suppress some httpdomain warnings in non web packages
         if "swh-web" not in app.srcdir:
 
             # filter out httpdomain unresolved reference warnings
@@ -286,6 +286,21 @@ def setup(app):
                 def filter(self, record: logging.LogRecord) -> bool:
                     return not record.msg.startswith("Cannot resolve reference to")
 
-            logger = logging.getLogger("sphinx")
-            # insert a custom filter in the warning log handler of sphinx
-            logger.handlers[1].filters.insert(0, HttpDomainWarningFilter())
+        # suppress some httpdomain warnings in web package
+        else:
+
+            # filter out non critical warnings appeared with sphinx 4.1 release
+            # TODO: remove that hack when that pull request gets merged
+            #       https://github.com/sphinx-contrib/httpdomain/pull/51
+            class HttpDomainWarningFilter(logging.Filter):
+                def filter(self, record: logging.LogRecord) -> bool:
+                    return not (
+                        record.args
+                        and type(record.args) == tuple  # to keep mypy happy
+                        and record.args[0] == "http"
+                        and record.msg.endswith("but that role is not in the domain.")
+                    )
+
+        logger = logging.getLogger("sphinx")
+        # insert a custom filter in the warning log handler of sphinx
+        logger.handlers[1].filters.insert(0, HttpDomainWarningFilter())