iOS photo extension finishContentEditingWithCompletionHandler: Unable to Save Changes

Question

My photo extension app has access to both Camera and Photos. All is ok, but when pressing Done, it can not save image.

Code of standard completion handler:

- (void)finishContentEditingWithCompletionHandler:(void (^)(PHContentEditingOutput *))completionHandler {
    // Update UI to reflect that editing has finished and output is being rendered.

    // Render and provide output on a background queue.
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        PHContentEditingOutput *output = [[PHContentEditingOutput alloc] initWithContentEditingInput:self.input];

        NSError* error = nil;

        NSData *renderedJPEGData = UIImageJPEGRepresentation(filtered_ui_image, 1.0);
        assert(renderedJPEGData != nil);
        //BOOL written_well = [renderedJPEGData writeToURL:output.renderedContentURL atomically:YES];

        BOOL written_well = [renderedJPEGData writeToURL:output.renderedContentURL options:NSDataWritingAtomic error:&error];
        assert(written_well);



        // Call completion handler to commit edit to Photos.
        completionHandler(output);
    });
}

renderedJPEGData is not nil,
error is nil, thus function [NSData writeToURL] was successful,
written_well is YES,

when debugging line-by-line, after block finishes, an alert appears:

output.renderedContentURL is /private/var/mobile/Containers/Data/PluginKitPlugin/509C1A04-D414-4DB7-B1E6-83C47FC88BC9/tmp/blah_blah_name.JPG

So, I have permissions, debug shows no errors, what can I try to detect the cause of problem?

Answer 1

As of iOS 10, the adjustment data must have at least one byte. This is a breaking change from iOS 9, where the adjustment data can be nil. I've tested this on both iOS 9 and iOS 10 to confirm.

Additional documentation: https://developer.apple.com/reference/photos/phcontenteditingoutput/1518684-adjustmentdata

PHContentEditingOutput* output = [[PHContentEditingOutput alloc] initWithContentEditingInput:self.input];
NSMutableData* adjustmentData = [NSMutableData data];
uint8_t byte = 1;
[adjustmentData appendBytes:&byte length:1];
output.adjustmentData = [[PHAdjustmentData alloc] initWithFormatIdentifier:@"com.yourcompany.yourapp" formatVersion:@"1.0f" data:adjustmentData];