swift-corelibs-foundation: [SR-2429] Regression: HTTPURLResponse allHeaderFields is now case-sensitive

Previous ID	SR-2429
Radar	rdar://27925651
Original Reporter	alexsporn (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Environment

Xcode Version 8.0 beta 6 (8S201h)

Additional Detail from JIRA

Votes	27
Component/s	Foundation
Labels	Bug
Assignee	@airspeedswift
Priority	Medium

md5: 2495a8cbf7aef0a067f006a363dbbfce

Issue Description:

HTTPURLResponse normalizes header names following RFC 2616 as described in https://developer.apple.com/reference/foundation/httpurlresponse/1417930-allheaderfields

Access to these header values is case-insensitive as described in the documentation. This is broken in the latest Xcode8 beta6. The access is now case-sensitive.

Additionally the “ETag” header name is normalized to “Etag” instead of “ETag” as described in RFC 2616

This works correctly on Xcode8 beta4

Steps to Reproduce:
Run following Swift code:

let url = URL(string: "http://www.apple.com")!

let headers = [
    "ETag" : "123456",
    "content-type": "application/json",
    ]

let urlResponse = HTTPURLResponse(url: url,
                                  statusCode: 200,
                                  httpVersion: nil,
                                  headerFields: headers)

print("ETag: \(urlResponse?.allHeaderFields["ETag"])")
print("Etag: \(urlResponse?.allHeaderFields["Etag"])")
print("ETAG: \(urlResponse?.allHeaderFields["ETAG"])")
print("etag: \(urlResponse?.allHeaderFields["etag"])")
print("content-type: \(urlResponse?.allHeaderFields["content-type"])")
print("Content-Type: \(urlResponse?.allHeaderFields["Content-Type"])")
print("CONTENT-TYPE: \(urlResponse?.allHeaderFields["CONTENT-TYPE"])")

Same code in Objective-C works as expected:

NSURL *url = [[NSURL alloc] initWithString:@"http://www.apple.com"];

NSDictionary *headers = @{
                          @"ETag": @"123456",
                          @"content-type": @"application/json",

                          };

NSURL *url = [[NSURL alloc] initWithString:@"http://www.apple.com"];

NSDictionary *headers = @{
                          @"ETag": @"123456",
                          @"content-type": @"application/json",

                          };

NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:url
                                                          statusCode:200
                                                         HTTPVersion:nil
                                                        headerFields:headers];

NSLog(@"Headers: %@", response.allHeaderFields);

NSLog(@"ETag: %@", response.allHeaderFields[@"ETag"]);
NSLog(@"Etag: %@", response.allHeaderFields[@"Etag"]);
NSLog(@"etag: %@", response.allHeaderFields[@"etag"]);
NSLog(@"ETAG: %@", response.allHeaderFields[@"ETAG"]);
NSLog(@"content-type: %@", response.allHeaderFields[@"content-type"]);
NSLog(@"Content-Type: %@", response.allHeaderFields[@"Content-Type"]);
NSLog(@"CONTENT-TYPE: %@", response.allHeaderFields[@"CONTENT-TYPE"]);

Expected Results:

Headers: Optional([AnyHashable("Content-Type"): application/json, AnyHashable("Etag"): 123456])
ETag: Optional(123456)
Etag: Optional(123456)
ETAG: Optional(123456)
etag: Optional(123456)
content-type: Optional(application/json)
Content-Type: Optional(application/json)
CONTENT-TYPE: Optional(application/json)

Actual Results:

Headers: Optional([AnyHashable("Content-Type"): application/json, AnyHashable("Etag"): 123456])
ETag: nil
Etag: Optional(123456)
ETAG: nil
etag: nil
content-type: nil
Content-Type: Optional(application/json)
CONTENT-TYPE: nil

Version:
Version 8.0 beta 6 (8S201h)