search_pill: Prevent adding duplicate search pills.

We shouldn't show duplicate suggestions in the typeahead, but
duplicate pills were still possible by typing a term twice in
the search bar and pressing enter after each one, and this
commit prevents that from putting duplicate pills in the search
bar.

web/src/search_pill.ts

@@ -178,9 +178,13 @@ export function set_search_bar_contents(
     let partial_pill = "";
     const invalid_inputs = [];
     const search_operator_strings = [];
+    const added_pills_as_input_strings = new Set(); // to prevent duplicating terms
 
     for (const term of search_terms) {
         const input = Filter.unparse([term]);
+        if (added_pills_as_input_strings.has(input)) {
+            return;
+        }
 
         // If the last term looks something like `dm:`, we
         // don't want to make it a pill, since it isn't isn't
@@ -215,10 +219,13 @@ export function set_search_bar_contents(
                 return user;
             });
             append_user_pill(users, pill_widget, term.operator, term.negated ?? false);
+            added_pills_as_input_strings.add(input);
         } else if (term.operator === "search") {
+            // This isn't a pill, so we don't add it to `added_pills_as_input_strings`
             search_operator_strings.push(input);
         } else {
             pill_widget.appendValue(input);
+            added_pills_as_input_strings.add(input);
         }
     }
     pill_widget.clear_text();

web/tests/search.test.cjs

@@ -384,3 +384,32 @@ run_test("initiate_search", ({override_rewire}) => {
     assert.ok(search_bar_opened);
     assert.equal($("#search_query").text(), "");
 });
+
+run_test("set_search_bar_contents with duplicate pills", () => {
+    const duplicate_attachment_terms = [
+        {
+            negated: false,
+            operator: "has",
+            operand: "attachment",
+        },
+        {
+            negated: false,
+            operator: "has",
+            operand: "attachment",
+        },
+    ];
+    search_pill.set_search_bar_contents(
+        duplicate_attachment_terms,
+        search.search_pill_widget,
+        false,
+        noop,
+    );
+    const pills = search.search_pill_widget._get_pills_for_testing();
+    assert.equal(pills.length, 1);
+    assert.deepEqual(pills[0].item, {
+        type: "search",
+        operator: "has",
+        operand: "attachment",
+        negated: false,
+    });
+});