Remove filter_term() shim function.

The filter_term() function was supporting the transition
from using tuples for search terms to using dictionaries,
but now all of the JS code should be dictionary-compatible.
(We had already abandoned the tuples safety net on staging,
and a couple days of use have given me confidence we can
pull the shim code.)

The one side effect this change has is that search terms will be
initialized to {} instead of [].  This distinction matters
when it comes to calling JSON.stringify on the search terms.

(imported from commit 1fbe11011d8953dbea28c0657cbf88384d343e00)

static/js/feature_flags.js

@@ -55,7 +55,6 @@ exports.propagate_topic_edits = true;
 exports.summarize_read_while_narrowed = false;
 exports.clicking_notification_causes_narrow = true;
 exports.use_socket = true;
-exports.remove_filter_tuples_safety_net = page_params.staging;
 
 // Ready for deprecation.
 exports.collapsible = false;

static/js/filter.js

@@ -1,25 +1,5 @@
 var Filter = (function () {
 
-function filter_term(opts) {
-    // For legacy reasons we must represent filter_terms as tuples
-    // until we phase out all the code that assumes tuples.
-    // We are very close to removing the tuple code everywhere; for
-    // now, we remove the safety net on staging only.
-    var term = [];
-
-    if (!feature_flags.remove_filter_tuples_safety_net) {
-        term[0] = opts.operator;
-        term[1] = opts.operand;
-    }
-
-    // This is the new style we are phasing in.  (Yes, the same
-    // object can be treated like either a tuple or a struct.)
-    term.operator = opts.operator;
-    term.operand = opts.operand;
-
-    return term;
-}
-
 function mit_edu_stream_name_match(message, operand) {
     // MIT users expect narrowing to "social" to also show messages to /^(un)*social(.d)*$/
     // (unsocial, ununsocial, social.d, etc)
@@ -188,10 +168,10 @@ Filter.canonicalize_term = function (opts) {
     }
 
     // We may want to consider allowing mixed-case operators at some point
-    return filter_term({
+    return {
         operator: operator,
         operand: operand
-    });
+    };
 };
 
 
@@ -239,7 +219,7 @@ Filter.parse = function (str) {
             // FIXME: Should we skip unknown operator names here?
             operator = parts.shift();
             operand = decodeOperand(parts.join(':'), operator);
-            term = filter_term({operator: operator, operand: operand});
+            term = {operator: operator, operand: operand};
             operators.push(term);
         }
     });
@@ -247,7 +227,7 @@ Filter.parse = function (str) {
     if (search_term.length > 0) {
         operator = 'search';
         operand = search_term.join(' ');
-        term = filter_term({operator: operator, operand: operand});
+        term = {operator: operator, operand: operand};
         operators.push(term);
     }
     return operators;

zerver/tests/frontend/node/filter.js

@@ -7,9 +7,6 @@ set_global('page_params', {
     email: 'hamlet@zulip.com',
     domain: 'zulip.com'
 });
-set_global('feature_flags', {
-    remove_filter_tuples_safety_net: false
-});
 
 var Filter = require('js/filter.js');
 var _ = global._;

zerver/tests/frontend/node/narrow.js

@@ -8,10 +8,6 @@ var Filter = global.Filter;
 var stream_data = global.stream_data;
 var _ = global._;
 
-set_global('feature_flags', {
-    remove_filter_tuples_safety_net: false
-});
-
 function set_filter(operators) {
     operators = _.map(operators, function (op) {
         return {operator: op[0], operand: op[1]};

zerver/tests/frontend/node/search_suggestion.js

@@ -28,10 +28,6 @@ set_global('stream_data', {
 
 set_global('narrow', {});
 
-set_global('feature_flags', {
-    remove_filter_tuples_safety_net: false
-});
-
 (function test_basic_get_suggestions() {
     var query = 'fred';