From 422a1d1475bd3db41a05b1a36036f8ae0c27b3c9 Mon Sep 17 00:00:00 2001
From: Lain Soykaf <lain@lain.com>
Date: Tue, 27 Oct 2026 12:50:04 +0400
Subject: [PATCH] fix(filters): honour whole_word

The whole_word field was stored and returned by the API, but the regex
always used word boundaries. As in Mastodon, a filter with whole_word
false now also matches inside words.
---
 changelog.d/filter-whole-word.fix |  1 +
 lib/pleroma/filter.ex             | 11 +++++++----
 test/pleroma/filter_test.exs      | 11 +++++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)
 create mode 100644 changelog.d/filter-whole-word.fix

diff --git a/changelog.d/filter-whole-word.fix b/changelog.d/filter-whole-word.fix
new file mode 100644
index 000000000..a831a74cb
--- /dev/null
+++ b/changelog.d/filter-whole-word.fix
@@ -0,0 +1 @@
+Filters with whole_word set to false now also match inside words
diff --git a/lib/pleroma/filter.ex b/lib/pleroma/filter.ex
index 3ab44efb0..fe3fb1c27 100644
--- a/lib/pleroma/filter.ex
+++ b/lib/pleroma/filter.ex
@@ -212,7 +212,7 @@ defmodule Pleroma.Filter do
 
     phrases =
       filters
-      |> Enum.map(&phrase_regex(&1.phrase, boundary))
+      |> Enum.map(&phrase_regex(&1, boundary))
       |> Enum.join("|")
 
     case format do
@@ -223,9 +223,12 @@ defmodule Pleroma.Filter do
 
   def compose_regex(_, _), do: nil
 
-  # Phrases are literal text. Like Mastodon, only add a word boundary
-  # where the phrase starts or ends with a word character.
-  defp phrase_regex(phrase, boundary) do
+  # Phrases are literal text. Like Mastodon, whole-word filters only get a
+  # word boundary where the phrase starts or ends with a word character.
+  defp phrase_regex(%__MODULE__{phrase: phrase, whole_word: false}, _boundary),
+    do: Regex.escape(phrase)
+
+  defp phrase_regex(%__MODULE__{phrase: phrase}, boundary) do
     prefix = if String.match?(phrase, ~r/^\w/u), do: boundary, else: ""
     suffix = if String.match?(phrase, ~r/\w$/u), do: boundary, else: ""
 
diff --git a/test/pleroma/filter_test.exs b/test/pleroma/filter_test.exs
index 5018b30bc..2fc72d9f5 100644
--- a/test/pleroma/filter_test.exs
+++ b/test/pleroma/filter_test.exs
@@ -233,6 +233,17 @@ defmodule Pleroma.FilterTest do
       end
     end
 
+    test "matches inside words when whole_word is false" do
+      filters = [%Filter{phrase: "cat", whole_word: false}, %Filter{phrase: "dog"}]
+      pg = Filter.compose_regex(filters)
+      re = Filter.compose_regex(filters, :re)
+
+      for {text, expected} <- [{"a catalog", true}, {"a hotdog", false}, {"a dog", true}] do
+        assert pg_match?(pg, text) == expected
+        assert Regex.match?(re, text) == expected
+      end
+    end
+
     test "keeps word boundaries for every phrase in Elixir" do
       regex = Filter.compose_regex(filters(["cat", "dog"]), :re)