[repo-assist] Ignore unknown Lua search-filter results (#2930)

fix(query): ignore unknown search filter results

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

pkg/query/query_builder.go

@@ -397,7 +397,9 @@ func (s *SourceQueryBuilder) applySearchFilter(results []abstractResult) []abstr
 
 	filtered := make([]abstractResult, 0, len(refs))
 	for _, ref := range refs {
-		filtered = append(filtered, byRef[ref])
+		if result, ok := byRef[ref]; ok {
+			filtered = append(filtered, result)
+		}
 	}
 
 	return filtered

pkg/query/query_builder_searchfilter_test.go

@@ -76,3 +76,32 @@ func TestSourceQueryBuilderSearchFilterHook(t *testing.T) {
 			"every result after the SearchFilter hook must be from aur")
 	}
 }
+
+func TestSourceQueryBuilderSearchFilterHookSkipsUnknownResults(t *testing.T) {
+	t.Parallel()
+
+	e := settingslua.New()
+	defer e.Close()
+
+	require.NoError(t, e.L.DoString(`
+		yay.create_autocmd("SearchFilter", {
+			callback = function(_)
+				return {
+					{ source = "aur", name = "known" },
+					{ source = "aur", name = "unknown" },
+				}
+			end,
+		})
+	`))
+
+	builder := &SourceQueryBuilder{
+		lua:    e,
+		logger: text.NewLogger(io.Discard, io.Discard, strings.NewReader(""), true, "test"),
+	}
+	filtered := builder.applySearchFilter([]abstractResult{
+		{source: "aur", name: "known", description: "known package"},
+	})
+
+	require.Len(t, filtered, 1)
+	assert.Equal(t, "known", filtered[0].name)
+}