make blocking subdomains configurable

doc/help/settings.asciidoc

@@ -142,6 +142,7 @@
 |<<content.autoplay,content.autoplay>>|Automatically start playing `<video>` elements.
 |<<content.blocking.adblock.lists,content.blocking.adblock.lists>>|List of URLs to ABP-style adblocking rulesets.
 |<<content.blocking.enabled,content.blocking.enabled>>|Enable the ad/host blocker
+|<<content.blocking.hosts.block_subdomains,content.blocking.hosts.block_subdomains>>|Block subdomains of blocked hosts.
 |<<content.blocking.hosts.lists,content.blocking.hosts.lists>>|List of URLs to host blocklists for the host blocker.
 |<<content.blocking.method,content.blocking.method>>|Which method of blocking ads should be used.
 |<<content.blocking.whitelist,content.blocking.whitelist>>|A list of patterns that should always be loaded, despite being blocked by the ad-/host-blocker.
@@ -1994,6 +1995,14 @@ Type: <<types,Bool>>
 
 Default: +pass:[true]+
 
+[[content.blocking.hosts.block_subdomains]]
+=== content.blocking.hosts.block_subdomains
+Block subdomains of blocked hosts.
+
+Type: <<types,Bool>>
+
+Default: +pass:[true]+
+
 [[content.blocking.hosts.lists]]
 === content.blocking.hosts.lists
 List of URLs to host blocklists for the host blocker.

qutebrowser/components/hostblock.py

@@ -132,10 +132,15 @@ class HostBlocker:
 
         host = request_url.host()
 
-        return any(
-            hostname in self._blocked_hosts or hostname in self._config_blocked_hosts
-            for hostname in urlutils.widened_hostnames(host)
-        )
+        if config.get("content.blocking.hosts.block_subdomains"):
+            return any(
+                hostname in self._blocked_hosts or hostname in self._config_blocked_hosts
+                for hostname in urlutils.widened_hostnames(host)
+            )
+        else:
+            return (
+                host in self._blocked_hosts or host in self._config_blocked_hosts
+            )
 
     def filter_request(self, info: interceptor.Request) -> None:
         """Block the given request if necessary."""

qutebrowser/config/configdata.yml

@@ -747,6 +747,11 @@ content.blocking.hosts.lists:
 
     The file `~/.config/qutebrowser/blocked-hosts` is always read if it exists.
 
+content.blocking.hosts.block_subdomains:
+  default: true
+  type: Bool
+  desc: Block subdomains of blocked hosts.
+
 content.blocking.method:
   default: auto
   type:

tests/unit/components/test_hostblock.py

@@ -570,4 +570,7 @@ def test_subdomain_blocking(config_stub, host_blocker_factory):
     config_stub.val.content.blocking.hosts.lists = None
     host_blocker = host_blocker_factory()
     host_blocker._blocked_hosts.add("example.com")
+    config_stub.val.content.blocking.hosts.block_subdomains = True
     assert host_blocker._is_blocked(QUrl("https://subdomain.example.com"))
+    config_stub.val.content.blocking.hosts.block_subdomains = False
+    assert not host_blocker._is_blocked(QUrl("https://subdomain.example.com"))