feed: viewer mute/block — mute actors/tags/objects + apply-prefs bag + 9 tests

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/feed/conformance.sh

@@ -13,7 +13,7 @@ if [ ! -x "$SX_SERVER" ]; then
   exit 1
 fi
 
-SUITES=(basic fanout rank integration content notify home dedupe trending)
+SUITES=(basic fanout rank integration content notify home dedupe trending mute)
 
 OUT_JSON="lib/feed/scoreboard.json"
 OUT_MD="lib/feed/scoreboard.md"
@@ -41,6 +41,7 @@ run_suite() {
 (load "lib/feed/notify.sx")
 (load "lib/feed/home.sx")
 (load "lib/feed/trending.sx")
+(load "lib/feed/mute.sx")
 (epoch 2)
 (eval "(define feed-test-pass 0)")
 (eval "(define feed-test-fail 0)")

lib/feed/mute.sx

@@ -0,0 +1,44 @@
+; feed/mute — viewer-controlled filtering. ACL (acl.sx) is author-controlled
+; visibility; mute is the reader's own preference: hide muted actors or tags.
+; Like ACL it is per-viewer and applied per request, never cached.
+;
+; Requires: lib/feed/normalize.sx, lib/feed/stream.sx, lib/feed/fanout.sx
+; (feed/-elem?).
+
+; drop activities authored by a muted actor
+(define
+  feed/mute-actors
+  (fn
+    (stream actors)
+    (feed/filter
+      stream
+      (fn (a) (not (feed/-elem? (get a :actor) actors))))))
+
+; drop activities carrying any muted tag
+(define
+  feed/mute-tags
+  (fn
+    (stream tags)
+    (feed/filter
+      stream
+      (fn (a) (not (some (fn (t) (feed/-elem? t tags)) (get a :tags)))))))
+
+; drop activities about a muted object (thread mute)
+(define
+  feed/mute-objects
+  (fn
+    (stream objects)
+    (feed/filter
+      stream
+      (fn (a) (not (feed/-elem? (get a :object) objects))))))
+
+; apply a viewer preference bag: {:mute-actors (...) :mute-tags (...) :mute-objects (...)}
+(define
+  feed/apply-prefs
+  (fn
+    (stream prefs)
+    (feed/mute-objects
+      (feed/mute-tags
+        (feed/mute-actors stream (get prefs :mute-actors (list)))
+        (get prefs :mute-tags (list)))
+      (get prefs :mute-objects (list)))))

lib/feed/scoreboard.json

@@ -8,9 +8,10 @@
     "notify": {"pass": 8, "fail": 0},
     "home": {"pass": 6, "fail": 0},
     "dedupe": {"pass": 9, "fail": 0},
-    "trending": {"pass": 11, "fail": 0}
+    "trending": {"pass": 11, "fail": 0},
+    "mute": {"pass": 9, "fail": 0}
   },
-  "total_pass": 154,
+  "total_pass": 163,
   "total_fail": 0,
-  "total": 154
+  "total": 163
 }

lib/feed/scoreboard.md

@@ -13,4 +13,5 @@ _Generated by `lib/feed/conformance.sh`_
 | home | 6 | 0 | 6 |
 | dedupe | 9 | 0 | 9 |
 | trending | 11 | 0 | 11 |
-| **Total** | **154** | **0** | **154** |
+| mute | 9 | 0 | 9 |
+| **Total** | **163** | **0** | **163** |

lib/feed/tests/mute.sx

@@ -0,0 +1,68 @@
+; Follow-up — viewer mute/block filtering. (feed-test name got expected)
+
+(define
+  S
+  (feed/stream
+    (list
+      (feed/normalize {:actor "alice" :object "P1" :at 1 :tags (list "news")})
+      (feed/normalize {:actor "bob" :object "P2" :at 2 :tags (list "spam")})
+      (feed/normalize {:actor "alice" :object "P3" :at 3 :tags (list "cats")})
+      (feed/normalize {:actor "carol" :object "P4" :at 4 :tags (list "news" "spam")}))))
+
+; ---------- mute actors ----------
+
+(feed-test
+  "mute bob drops his post"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-actors S (list "bob"))))
+  (list "P1" "P3" "P4"))
+(feed-test
+  "mute alice drops two"
+  (feed/count (feed/mute-actors S (list "alice")))
+  2)
+(feed-test
+  "mute nobody keeps all"
+  (feed/count (feed/mute-actors S (list)))
+  4)
+
+; ---------- mute tags ----------
+
+(feed-test
+  "mute spam tag drops two"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-tags S (list "spam"))))
+  (list "P1" "P3"))
+(feed-test
+  "mute news+cats leaves spam-only"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/mute-tags S (list "news" "cats"))))
+  (list "P2"))
+
+; ---------- mute objects ----------
+
+(feed-test
+  "mute object P3 (thread mute)"
+  (feed/count (feed/mute-objects S (list "P3")))
+  3)
+
+; ---------- combined prefs ----------
+
+(feed-test
+  "apply-prefs actors + tags"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/apply-prefs S {:mute-actors (list "bob") :mute-tags (list "cats")})))
+  (list "P1" "P4"))
+(feed-test
+  "apply-prefs empty keeps all"
+  (feed/count (feed/apply-prefs S {}))
+  4)
+(feed-test
+  "apply-prefs all three filters"
+  (map
+    (fn (a) (get a :object))
+    (feed/items (feed/apply-prefs S {:mute-objects (list "P3") :mute-actors (list "carol") :mute-tags (list "spam")})))
+  (list "P1"))

plans/feed-on-sx.md

@@ -14,7 +14,7 @@ APL, ACL visibility filtering via `lib/acl/`, federation via fed-sx.
 
 ## Status (rolling)
 
-`bash lib/feed/conformance.sh` → **154/154** (Phases 1–4 + TF-IDF + notifications + home + smart-dedupe + trending)
+`bash lib/feed/conformance.sh` → **163/163** (Phases 1–4 + TF-IDF, notifications, home, smart-dedupe, trending, mute)
 
 ## Ground rules
 
@@ -154,6 +154,9 @@ are function parameters. Real acl-sx / fed-sx wire in at the call site unchanged
 - [x] Trending — `feed/trending` / `feed/trending-actors`: objects/actors ranked
   by activity count in a recency window, count-desc with key-asc tiebreak
   (`trending.sx`); 11 tests. (154/154 total.)
+- [x] Mute/block — `feed/mute-actors` / `feed/mute-tags` / `feed/mute-objects` /
+  `feed/apply-prefs`: viewer-controlled per-request filtering (complements ACL's
+  author-controlled visibility) (`mute.sx`); 9 tests. (163/163 total.)
 
 (none)