Add support for changing the actions for default rules

See matrix-org/matrix-doc#283

Works by adding dummy rules to the push rules table with a negative priority class and then using those rules to clobber the default rule actions when adding the default rules in ``list_with_base_rules``

1 files changed, 50 insertions, 7 deletions

diff --git a/synapse/push/baserules.py b/synapse/push/baserules.py
index 0832c77cb4..86a2998bcc 100644
--- a/synapse/push/baserules.py
+++ b/synapse/push/baserules.py
@@ -13,46 +13,67 @@
 # limitations under the License.
 
 from synapse.push.rulekinds import PRIORITY_CLASS_MAP, PRIORITY_CLASS_INVERSE_MAP
+import copy
 
 
 def list_with_base_rules(rawrules):
+    """Combine the list of rules set by the user with the default push rules
+
+    :param list rawrules: The rules the user has modified or set.
+    :returns: A new list with the rules set by the user combined with the
+        defaults.
+    """
     ruleslist = []
 
+    # Grab the base rules that the user has modified.
+    # The modified base rules have a priority_class of -1.
+    modified_base_rules = {
+        r['rule_id']: r for r in rawrules if r['priority_class'] < 0
+    }
+
+    # Remove the modified base rules from the list, They'll be added back
+    # in the default postions in the list.
+    rawrules = [r for r in rawrules if r['priority_class'] >= 0]
+
     # shove the server default rules for each kind onto the end of each
     current_prio_class = PRIORITY_CLASS_INVERSE_MAP.keys()[-1]
 
     ruleslist.extend(make_base_prepend_rules(
-        PRIORITY_CLASS_INVERSE_MAP[current_prio_class]
+        PRIORITY_CLASS_INVERSE_MAP[current_prio_class], modified_base_rules
     ))
 
     for r in rawrules:
         if r['priority_class'] < current_prio_class:
             while r['priority_class'] < current_prio_class:
                 ruleslist.extend(make_base_append_rules(
-                    PRIORITY_CLASS_INVERSE_MAP[current_prio_class]
+                    PRIORITY_CLASS_INVERSE_MAP[current_prio_class],
+                    modified_base_rules,
                 ))
                 current_prio_class -= 1
                 if current_prio_class > 0:
                     ruleslist.extend(make_base_prepend_rules(
-                        PRIORITY_CLASS_INVERSE_MAP[current_prio_class]
+                        PRIORITY_CLASS_INVERSE_MAP[current_prio_class],
+                        modified_base_rules,
                     ))
 
         ruleslist.append(r)
 
     while current_prio_class > 0:
         ruleslist.extend(make_base_append_rules(
-            PRIORITY_CLASS_INVERSE_MAP[current_prio_class]
+            PRIORITY_CLASS_INVERSE_MAP[current_prio_class],
+            modified_base_rules,
         ))
         current_prio_class -= 1
         if current_prio_class > 0:
             ruleslist.extend(make_base_prepend_rules(
-                PRIORITY_CLASS_INVERSE_MAP[current_prio_class]
+                PRIORITY_CLASS_INVERSE_MAP[current_prio_class],
+                modified_base_rules,
             ))
 
     return ruleslist
 
 
-def make_base_append_rules(kind):
+def make_base_append_rules(kind, modified_base_rules):
     rules = []
 
     if kind == 'override':
@@ -62,15 +83,31 @@ def make_base_append_rules(kind):
     elif kind == 'content':
         rules = BASE_APPEND_CONTENT_RULES
 
+    # Copy the rules before modifying them
+    rules = copy.deepcopy(rules)
+    for r in rules:
+        # Only modify the actions, keep the conditions the same.
+        modified = modified_base_rules.get(r['rule_id'])
+        if modified:
+            r['actions'] = modified['actions']
+
     return rules
 
 
-def make_base_prepend_rules(kind):
+def make_base_prepend_rules(kind, modified_base_rules):
     rules = []
 
     if kind == 'override':
         rules = BASE_PREPEND_OVERRIDE_RULES
 
+    # Copy the rules before modifying them
+    rules = copy.deepcopy(rules)
+    for r in rules:
+        # Only modify the actions, keep the conditions the same.
+        modified = modified_base_rules.get(r['rule_id'])
+        if modified:
+            r['actions'] = modified['actions']
+
     return rules
 
 
@@ -263,18 +300,24 @@ BASE_APPEND_UNDERRIDE_RULES = [
 ]
 
 
+BASE_RULE_IDS = set()
+
 for r in BASE_APPEND_CONTENT_RULES:
     r['priority_class'] = PRIORITY_CLASS_MAP['content']
     r['default'] = True
+    BASE_RULE_IDS.add(r['rule_id'])
 
 for r in BASE_PREPEND_OVERRIDE_RULES:
     r['priority_class'] = PRIORITY_CLASS_MAP['override']
     r['default'] = True
+    BASE_RULE_IDS.add(r['rule_id'])
 
 for r in BASE_APPEND_OVRRIDE_RULES:
     r['priority_class'] = PRIORITY_CLASS_MAP['override']
     r['default'] = True
+    BASE_RULE_IDS.add(r['rule_id'])
 
 for r in BASE_APPEND_UNDERRIDE_RULES:
     r['priority_class'] = PRIORITY_CLASS_MAP['underride']
     r['default'] = True
+    BASE_RULE_IDS.add(r['rule_id'])