From faa162714412e1d10af318819adaad5b80eaa4b2 Mon Sep 17 00:00:00 2001
From: Robin Macharg <robin.macharg+github@gmail.com>
Date: Tue, 18 Feb 2020 13:41:46 +0000
Subject: [PATCH] feat: Added a mutable Bugsnag.context property

---
 CHANGELOG.md          |  5 +++++
 Source/Bugsnag.h      |  8 ++++++++
 Source/Bugsnag.m      |  4 ++++
 Source/BugsnagEvent.m | 12 ++++++++++-
 Tests/BugsnagTests.m  | 47 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0604da6fc..7d3cfb1b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,11 @@ Bugsnag Notifiers on other platforms.
   `BugsnagConfiguration` value but can be overridden in event passed to the 
   `Bugsnag.notify()` callback.
   [#458](https://github.com/bugsnag/bugsnag-cocoa/pull/458)
+  
+  * Added `Bugsnag.context`, replicating the `BugsnagConfiguration` property.  This is
+  mutable and may be changed at any point.  Changes are propagated to the `BugsnagConfiguration`
+  property.
+  [#466](https://github.com/bugsnag/bugsnag-cocoa/pull/466)
 
 * `Bugsnag.stopSession()` is now `Bugsnag.pauseSession()`.  This renaming has 
    also been applied to the `BugsnagNotifier` and `BugsnagSessionTracker` classes.
diff --git a/Source/Bugsnag.h b/Source/Bugsnag.h
index 780b12e21..b8e44d941 100644
--- a/Source/Bugsnag.h
+++ b/Source/Bugsnag.h
@@ -300,4 +300,12 @@ static NSString *_Nonnull const BugsnagSeverityInfo = @"info";
 + (void)setBreadcrumbCapacity:(NSUInteger)capacity
         __deprecated_msg("Use [BugsnagConfiguration setMaxBreadcrumbs:] instead");
 
+
+/**
+ * Replicates BugsnagConfiguration.context
+ *
+ * @param context A general summary of what was happening in the application
+ */
++ (void)setContext:(NSString *_Nullable)context;
+
 @end
diff --git a/Source/Bugsnag.m b/Source/Bugsnag.m
index 0ed1fe340..3de54824d 100644
--- a/Source/Bugsnag.m
+++ b/Source/Bugsnag.m
@@ -314,6 +314,10 @@ + (id _Nullable )getMetadata:(NSString *_Nonnull)section
     return [[[self configuration] metadata] getMetadata:section key:key];
 }
 
++ (void)setContext:(NSString *_Nullable)context {
+    [self configuration].context = context;
+}
+
 @end
 
 //
diff --git a/Source/BugsnagEvent.m b/Source/BugsnagEvent.m
index cb3777ca6..3fd6868e0 100644
--- a/Source/BugsnagEvent.m
+++ b/Source/BugsnagEvent.m
@@ -109,6 +109,15 @@ id BSGLoadConfigValue(NSDictionary *report, NSString *valueName) {
     ?: [report valueForKeyPath:fallbackKeypath]; // some custom values are nested
 }
 
+/**
+ * Attempt to find a context (within which the event is being reported)
+ * This can be found in user-set metadata of varying specificity or the global
+ * configuration.  Returns nil if no context can be found.
+ *
+ * @param report A dictionary of report data
+ * @param metadata Additional relevant data
+ * @returns A string context if found, or nil
+ */
 NSString *BSGParseContext(NSDictionary *report, NSDictionary *metadata) {
     id context = [report valueForKeyPath:@"user.overrides.context"];
     if ([context isKindOfClass:[NSString class]])
@@ -333,7 +342,8 @@ - (instancetype)initWithKSReport:(NSDictionary *)report {
         _metadata = metadata ?: [NSDictionary new];
         _releaseStage = config.releaseStage;
         _notifyReleaseStages = config.notifyReleaseStages;
-        _context = BSGParseContext(nil, metadata);
+        // Set context based on current values.  May be nil.
+        _context = metadata[BSGKeyContext] ?: [[Bugsnag configuration] context];
         _breadcrumbs = [config.breadcrumbs arrayValue];
         _overrides = [NSDictionary new];
 
diff --git a/Tests/BugsnagTests.m b/Tests/BugsnagTests.m
index 597e2d6da..8f81379d5 100644
--- a/Tests/BugsnagTests.m
+++ b/Tests/BugsnagTests.m
@@ -129,4 +129,51 @@ -(void)testBugsnagPauseSession {
     [Bugsnag pauseSession];
 }
 
+/**
+ * Test that the BugsnagConfiguration-mirroring Bugsnag.context is mutable
+ */
+- (void)testMutableContext {
+    // Allow for checks inside blocks that may (potentially) be run asynchronously
+    __block XCTestExpectation *expectation1 = [self expectationWithDescription:@"Localized metadata changes"];
+    
+    NSError *error;
+    BugsnagConfiguration *configuration = [[BugsnagConfiguration alloc] initWithApiKey:DUMMY_APIKEY_32CHAR_1 error:&error];
+    [configuration setContext:@"firstContext"];
+    [configuration addBeforeSendBlock:^bool(NSDictionary * _Nonnull rawEventData,
+                                            BugsnagEvent * _Nonnull reports)
+    {
+        return false;
+    }];
+    
+    [Bugsnag startBugsnagWithConfiguration:configuration];
+
+    NSException *exception1 = [[NSException alloc] initWithName:@"exception1" reason:@"reason1" userInfo:nil];
+
+    // Check that the context is set going in to the test and that we can change it
+    [Bugsnag notify:exception1 block:^(BugsnagEvent * _Nonnull event) {
+        XCTAssertEqual([[Bugsnag configuration] context], @"firstContext");
+        
+        // Change the global context
+        [Bugsnag setContext:@"secondContext"];
+        
+        // Check that it's made it into the configuration (from the point of view of the block)
+        // and that setting it here doesn't affect the event's value.
+        XCTAssertEqual([[Bugsnag configuration] context], @"secondContext");
+        XCTAssertEqual([event context], @"firstContext");
+        
+        [expectation1 fulfill];
+    }];
+
+    // Test that the context (changed inside the notify block) remains changed
+    // And that the event picks up this value.
+    [self waitForExpectationsWithTimeout:5.0 handler:^(NSError * _Nullable error) {
+        XCTAssertEqual([[Bugsnag configuration] context], @"secondContext");
+        
+        [Bugsnag notify:exception1 block:^(BugsnagEvent * _Nonnull report) {
+            XCTAssertEqual([[Bugsnag configuration] context], @"secondContext");
+            XCTAssertEqual([report context], @"secondContext");
+        }];
+    }];
+}
+
 @end