When passing in nil to clear the animated image, remove anything sitting in super.image

[michafaw]

We're already covering the case of clearing out super.nil when setAnimatedImage is not nil. This adds a small tweak to handle when you pass in nil.

[raphaelschaad]

Looks safe -- what bug does this fix?

[michafaw]

@raphaelschaad If you have already set an animated image, then sometimes you'll have an image in super.image. The bug is that it is not always being updated (removed). There's already code in place (in the if (super.image) block above my change) to cover changing animated images, but not when going from animated image to no image.
Let me know and I'll create an issue + example project to link to.

[raphaelschaad]

CHANGES 0723343

[freezy7]

this cause this method sd_set normal image reset image = nil

if (!isGIF) {
                               strongSelf.image = image;
                               strongSelf.animatedImage = nil;
                               return;
                           }

FLAnimatedImageView+WebCache.h

- (void)sd_setImageWithURL:(nullable NSURL *)url
          placeholderImage:(nullable UIImage *)placeholder
                   options:(SDWebImageOptions)options
                  progress:(nullable SDWebImageDownloaderProgressBlock)progressBlock
                 completed:(nullable SDExternalCompletionBlock)completedBlock {
    __weak typeof(self)weakSelf = self;
    [self sd_internalSetImageWithURL:url
                    placeholderImage:placeholder
                             options:options
                        operationKey:nil
                       setImageBlock:^(UIImage *image, NSData *imageData) {
                           __strong typeof(weakSelf)strongSelf = weakSelf;
                           if (!strongSelf) {
                               return;
                           }
                           // Step 1. Check memory cache (associate object)
                           FLAnimatedImage *associatedAnimatedImage = image.sd_FLAnimatedImage;
                           if (associatedAnimatedImage) {
                               // Asscociated animated image exist
                               strongSelf.animatedImage = associatedAnimatedImage;
                               strongSelf.image = nil;
                               return;
                           }
                           // Step 2. Check if original compressed image data is "GIF"
                           BOOL isGIF = (image.sd_imageFormat == SDImageFormatGIF || [NSData sd_imageFormatForImageData:imageData] == SDImageFormatGIF);
                           if (!isGIF) {
                               strongSelf.image = image;
                               strongSelf.animatedImage = nil;
                               return;
                           }
                           // Step 3. Check if data exist or query disk cache
                           if (!imageData) {
                               NSString *key = [[SDWebImageManager sharedManager] cacheKeyForURL:url];
                               imageData = [[SDImageCache sharedImageCache] diskImageDataForKey:key];
                           }
                           // Step 4. Create FLAnimatedImage
                           FLAnimatedImage *animatedImage = SDWebImageCreateFLAnimatedImage(strongSelf, imageData);
                           // Step 5. Set animatedImage or normal image
                           if (animatedImage) {
                               if (strongSelf.sd_cacheFLAnimatedImage) {
                                   image.sd_FLAnimatedImage = animatedImage;
                               }
                               strongSelf.animatedImage = animatedImage;
                               strongSelf.image = nil;
                           } else {
                               strongSelf.animatedImage = nil;
                               strongSelf.image = image;
                           }
                       }
                            progress:progressBlock
                           completed:completedBlock];
}

[matrush]

If you have already set an animated image, then sometimes you'll have an image in super.image.

This is not possible, as when we are setting the animated image we always check if there is super.image, if so, it will be cleared.

I feel this change itself doesn't make sense and causes the extra issues mentioned in the above. I will revert the changes for now.

[michafaw]

@matrush Seems the cure is worse than the problem here. I agree this small change should be reverted.

The side effect (as seen in freezy7's quoted code) is caused by the order of setting animatedImage to nil after setting image to something valid. That code has no issue without this PR's change. (And honestly, those same = nil lines are unnecessary. As you pointed out, we clear when we set, so there is no need for the extra line in each of those 5 steps.)

Additional thoughts: I find it confusing that iv.image = something wipes out animatedImage and iv.animatedImage = something wipes out image, but setting either of those to nil does not. With the exception of the way setting an animatedImage gives you access to its currentFrame via iv.image, the general analogy is that this is a UIImageView that shows one image, not two. The internals for resetting "the image" do not fully reflect that same analogy.