Preserve insertion order in feature flags

bugsnag · Jul 8, 2022 · 1c54a0c · 1c54a0c
1 parent 52b0b6f
commit 1c54a0c
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Showing 6 changed files with 73 additions and 28 deletions.
diff --git a/Bugsnag/BugsnagFeatureFlag.m b/Bugsnag/BugsnagFeatureFlag.m
@@ -26,4 +26,24 @@ - (instancetype)initWithName:(NSString *)name variant:(nullable NSString *)varia
     return self;
 }
 
+- (BOOL)isEqual:(id)object {
+    if (object == nil) {
+        return NO;
+    }
+
+    if (self == object) {
+        return YES;
+    }
+
+    if (![object isKindOfClass:[BugsnagFeatureFlag class]]) {
+        return NO;
+    }
+
+    BugsnagFeatureFlag *obj = (BugsnagFeatureFlag *)object;
+
+    // Ignore the variant when checking for equality. We only care if the name matches
+    // when checking for duplicates.
+    return [obj.name isEqualToString:self.name];
+}
+
 @end
diff --git a/Bugsnag/Client/BugsnagClient.m b/Bugsnag/Client/BugsnagClient.m
@@ -994,8 +994,8 @@ - (void)setObserver:(BSGClientObserver)observer {
         };
 
         @synchronized (self.featureFlagStore) {
-            for (NSString *name in self.featureFlagStore) {
-                observer(BSGClientObserverAddFeatureFlag, [BugsnagFeatureFlag flagWithName:name variant:self.featureFlagStore[name]]);
+            for (BugsnagFeatureFlag *flag in self.featureFlagStore) {
+                observer(BSGClientObserverAddFeatureFlag, flag);
             }
         }
     } else {

diff --git a/Bugsnag/Helpers/BSGFeatureFlagStore.h b/Bugsnag/Helpers/BSGFeatureFlagStore.h
@@ -10,7 +10,7 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-typedef NSMutableDictionary<NSString *, id> BSGFeatureFlagStore;
+typedef NSMutableArray<BugsnagFeatureFlag *> BSGFeatureFlagStore;
 
 void BSGFeatureFlagStoreAddFeatureFlag(BSGFeatureFlagStore *store, NSString *name, NSString *_Nullable variant);
 

diff --git a/Bugsnag/Helpers/BSGFeatureFlagStore.m b/Bugsnag/Helpers/BSGFeatureFlagStore.m
@@ -11,49 +11,53 @@
 #import "BSGKeys.h"
 #import "BugsnagFeatureFlag.h"
 
+static void internalAddFeatureFlag(BSGFeatureFlagStore *store, BugsnagFeatureFlag *flag) {
+    [store removeObject:flag];
+    [store addObject:flag];
+}
+
 void BSGFeatureFlagStoreAddFeatureFlag(BSGFeatureFlagStore *store, NSString *name, NSString *_Nullable variant) {
-    store[name] = variant ?: [NSNull null];
+    internalAddFeatureFlag(store, [BugsnagFeatureFlag flagWithName:name variant:variant]);
 }
 
 void BSGFeatureFlagStoreAddFeatureFlags(BSGFeatureFlagStore *store, NSArray<BugsnagFeatureFlag *> *featureFlags) {
     for (BugsnagFeatureFlag *featureFlag in featureFlags) {
-        store[featureFlag.name] = featureFlag.variant ?: [NSNull null];
+        internalAddFeatureFlag(store, featureFlag);
     }
 }
 
 void BSGFeatureFlagStoreClear(BSGFeatureFlagStore *store, NSString *_Nullable name) {
     if (name) {
-        [store removeObjectForKey:(NSString *_Nonnull)name];
+        [store removeObject:[BugsnagFeatureFlag flagWithName:(NSString * _Nonnull)name]];
     } else {
         [store removeAllObjects];
     }
 }
 
 NSArray<NSDictionary *> * BSGFeatureFlagStoreToJSON(BSGFeatureFlagStore *store) {
     NSMutableArray<NSDictionary *> *result = [NSMutableArray array];
-    for (NSString *name in store) {
-        id variant = store[name];
-        if ([variant isKindOfClass:[NSString class]]) {
-            [result addObject:@{BSGKeyFeatureFlag: name, BSGKeyVariant: variant}];
+    for (BugsnagFeatureFlag *flag in store) {
+        if (flag.variant) {
+            [result addObject:@{BSGKeyFeatureFlag: flag.name, BSGKeyVariant: (NSString * _Nonnull)flag.variant}];
         } else {
-            [result addObject:@{BSGKeyFeatureFlag: name}];
+            [result addObject:@{BSGKeyFeatureFlag: flag.name}];
         }
     }
-    [result sortUsingComparator:^NSComparisonResult(NSDictionary *_Nonnull obj1, NSDictionary *_Nonnull obj2) {
-        return [(NSString *)obj1[BSGKeyFeatureFlag] compare:(NSString *)obj2[BSGKeyFeatureFlag]];
-    }];
     return result;
 }
 
 BSGFeatureFlagStore * BSGFeatureFlagStoreFromJSON(id json) {
-    BSGFeatureFlagStore *store = [NSMutableDictionary dictionary];
+    BSGFeatureFlagStore *store = [NSMutableArray array];
     if ([json isKindOfClass:[NSArray class]]) {
         for (id item in json) {
             if ([item isKindOfClass:[NSDictionary class]]) {
                 NSString *featureFlag = item[BSGKeyFeatureFlag];
                 if ([featureFlag isKindOfClass:[NSString class]]) {
                     id variant = item[BSGKeyVariant];
-                    store[featureFlag] = [variant isKindOfClass:[NSString class]] ? variant : [NSNull null];
+                    if (![variant isKindOfClass:[NSString class]]) {
+                        variant = nil;
+                    }
+                    [store addObject:[BugsnagFeatureFlag flagWithName:featureFlag variant:variant]];
                 }
             }
         }

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,9 @@ Changelog
 
 ### Enhancements
 
+* Feature flags are now kept in order of insertion or modification rather than in alphabetical order.
+  [#1429](https://github.com/bugsnag/bugsnag-android/pull/1429)
+
 * Send usage telemetry to Bugsnag for product improvement purposes. Can be disabled using `configuration.telemetry`.
   [#1422](https://github.com/bugsnag/bugsnag-cocoa/pull/1422)
 

diff --git a/Tests/BugsnagTests/BSGFeatureFlagStoreTests.m b/Tests/BugsnagTests/BSGFeatureFlagStoreTests.m
@@ -19,27 +19,45 @@ @implementation BSGFeatureFlagStoreTests
 - (void)test {
     BSGFeatureFlagStore *store = [[BSGFeatureFlagStore alloc] init];
     XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store), @[]);
-    
-    BSGFeatureFlagStoreAddFeatureFlag(store, @"featureA", @"enabled");
+
+    BSGFeatureFlagStoreAddFeatureFlag(store, @"featureC", @"checked");
     XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store),
-                          (@[@{@"featureFlag": @"featureA", @"variant": @"enabled"}]));
+                          (@[@{@"featureFlag": @"featureC", @"variant": @"checked"}]));
 
-    BSGFeatureFlagStoreAddFeatureFlags(store, @[[BugsnagFeatureFlag flagWithName:@"featureA"]]);
+    BSGFeatureFlagStoreAddFeatureFlag(store, @"featureA", @"enabled");
     XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store),
-                          @[@{@"featureFlag": @"featureA"}]);
-
+                          (@[
+                            @{@"featureFlag": @"featureC", @"variant": @"checked"},
+                            @{@"featureFlag": @"featureA", @"variant": @"enabled"}
+                          ]));
+
     BSGFeatureFlagStoreAddFeatureFlag(store, @"featureB", nil);
     XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store),
-                          (@[@{@"featureFlag": @"featureA"},
-                             @{@"featureFlag": @"featureB"}]));
-
+                          (@[
+                            @{@"featureFlag": @"featureC", @"variant": @"checked"},
+                            @{@"featureFlag": @"featureA", @"variant": @"enabled"},
+                            @{@"featureFlag": @"featureB"}
+                          ]));
+
+
+    BSGFeatureFlagStoreAddFeatureFlags(store, @[[BugsnagFeatureFlag flagWithName:@"featureA"]]);
+    XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store),
+                          (@[
+                            @{@"featureFlag": @"featureC", @"variant": @"checked"},
+                            @{@"featureFlag": @"featureB"},
+                            @{@"featureFlag": @"featureA"}
+                          ]));
+
     XCTAssertEqualObjects(BSGFeatureFlagStoreFromJSON(BSGFeatureFlagStoreToJSON(store)),
                           store);
 
-    BSGFeatureFlagStoreClear(store, @"featureA");
+    BSGFeatureFlagStoreClear(store, @"featureB");
     XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store),
-                          @[@{@"featureFlag": @"featureB"}]);
-
+                          (@[
+                            @{@"featureFlag": @"featureC", @"variant": @"checked"},
+                            @{@"featureFlag": @"featureA"}
+                          ]));
+
     BSGFeatureFlagStoreClear(store, nil);
     XCTAssertEqualObjects(BSGFeatureFlagStoreToJSON(store), @[]);
 }