Added sd_isThumbnail to mark metadata, avoid the case when full size image request re-use the image from thumbnail decoding for the same URL

I think this is a temp workaround

SDWebImage/Core/SDImageCacheDefine.m

@@ -14,6 +14,8 @@
 #import "SDInternalMacros.h"
 
 UIImage * _Nullable SDImageCacheDecodeImageData(NSData * _Nonnull imageData, NSString * _Nonnull cacheKey, SDWebImageOptions options, SDWebImageContext * _Nullable context) {
+    NSCParameterAssert(imageData);
+    NSCParameterAssert(cacheKey);
     UIImage *image;
     BOOL decodeFirstFrame = SD_OPTIONS_CONTAINS(options, SDWebImageDecodeFirstFrameOnly);
     NSNumber *scaleValue = context[SDWebImageContextImageScaleFactor];
@@ -79,6 +81,8 @@ UIImage * _Nullable SDImageCacheDecodeImageData(NSData * _Nonnull imageData, NSS
         if (shouldDecode) {
             image = [SDImageCoderHelper decodedImageWithImage:image];
         }
+        // mark the image as thumbnail, to let manager check whether to re-decode if needed
+        image.sd_isThumbnail = thumbnailSizeValue != nil;
     }
     
     return image;

SDWebImage/Core/SDImageIOAnimatedCoder.m

@@ -311,11 +311,14 @@ static NSString * kSDCGImageDestinationRequestedFileSize = @"kCGImageDestination
     // Which decode frames in time and reduce memory usage
     if (thumbnailSize.width == 0 || thumbnailSize.height == 0) {
         SDAnimatedImageRep *imageRep = [[SDAnimatedImageRep alloc] initWithData:data];
-        NSSize size = NSMakeSize(imageRep.pixelsWide / scale, imageRep.pixelsHigh / scale);
-        imageRep.size = size;
-        NSImage *animatedImage = [[NSImage alloc] initWithSize:size];
-        [animatedImage addRepresentation:imageRep];
-        return animatedImage;
+        if (imageRep) {
+            NSSize size = NSMakeSize(imageRep.pixelsWide / scale, imageRep.pixelsHigh / scale);
+            imageRep.size = size;
+            NSImage *animatedImage = [[NSImage alloc] initWithSize:size];
+            [animatedImage addRepresentation:imageRep];
+            animatedImage.sd_imageFormat = self.class.imageFormat;
+            return animatedImage;
+        }
     }
 #endif
     

SDWebImage/Core/SDImageLoader.m

@@ -106,6 +106,8 @@ UIImage * _Nullable SDImageLoaderDecodeImageData(NSData * _Nonnull imageData, NS
         if (shouldDecode) {
             image = [SDImageCoderHelper decodedImageWithImage:image];
         }
+        // mark the image as thumbnail, to let manager check whether to re-decode if needed
+        image.sd_isThumbnail = thumbnailSizeValue != nil;
     }
     
     return image;
@@ -204,6 +206,8 @@ UIImage * _Nullable SDImageLoaderDecodeProgressiveImageData(NSData * _Nonnull im
         }
         // mark the image as progressive (completed one are not mark as progressive)
         image.sd_isIncremental = !finished;
+        // mark the image as thumbnail, to let manager check whether to re-decode if needed
+        image.sd_isThumbnail = thumbnailSizeValue != nil;
     }
     
     return image;

SDWebImage/Core/SDWebImageManager.m

@@ -510,7 +510,7 @@ static id<SDImageLoader> _defaultImageLoader;
         // normally use the store cache type, but if target image is transformed, use original store cache type instead
         SDImageCacheType targetStoreCacheType = shouldTransformImage ? originalStoreCacheType : storeCacheType;
         UIImage *originalImage = downloadedImage;
-        BOOL thumbnailed = context[SDWebImageContextImageThumbnailPixelSize];
+        BOOL thumbnailed = context[SDWebImageContextImageThumbnailPixelSize] != nil;
         if (thumbnailed) {
             // Thumbnail decoding does not keep original image
             // Here we only store the original data to disk for original cache key
@@ -560,10 +560,16 @@ static id<SDImageLoader> _defaultImageLoader;
     }
     id<SDWebImageCacheSerializer> cacheSerializer = context[SDWebImageContextCacheSerializer];
     
+    // transformer check
     BOOL shouldTransformImage = originalImage && transformer;
     shouldTransformImage = shouldTransformImage && (!originalImage.sd_isAnimated || (options & SDWebImageTransformAnimatedImage));
     shouldTransformImage = shouldTransformImage && (!originalImage.sd_isVector || (options & SDWebImageTransformVectorImage));
-    // if available, store transformed image to cache
+    
+    // thumbnail check
+    // This exist when previous thumbnail pipeline callback into next full size pipeline, because we share the same URL download but need different image
+    // Actually this is a hack, we attach the metadata into image object, which should design a better concept like `ImageInfo` and keep that around
+    BOOL shouldDecodeFullImage = originalImage.sd_isThumbnail && context[SDWebImageContextImageThumbnailPixelSize] == nil;
+    
     if (shouldTransformImage) {
         dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
             @autoreleasepool {
@@ -587,6 +593,19 @@ static id<SDImageLoader> _defaultImageLoader;
                 }
             }
         });
+    } else if (shouldDecodeFullImage) {
+        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
+            @autoreleasepool {
+                // transformed/thumbnailed cache key
+                NSString *key = [self cacheKeyForURL:url context:context];
+                // disable thumbnail decoding
+                SDWebImageMutableContext *tempContext = [context mutableCopy];
+                tempContext[SDWebImageContextImageThumbnailPixelSize] = nil;
+                UIImage *originalImage = SDImageCacheDecodeImageData(originalData, key, options, tempContext);
+                // Continue store transform cache process
+                [self callStoreTransformCacheProcessForOperation:operation url:url options:options context:context image:originalImage data:originalData cacheType:cacheType transformed:NO finished:finished completed:completedBlock];
+            }
+        });
     } else {
         // Continue store transform cache process
         [self callStoreTransformCacheProcessForOperation:operation url:url options:options context:context image:originalImage data:originalData cacheType:cacheType transformed:NO finished:finished completed:completedBlock];
@@ -620,7 +639,7 @@ static id<SDImageLoader> _defaultImageLoader;
     // but the storeImage does not handle the thumbnail context option
     // to keep exist SDImageCache's impl compatible, we introduce this helper
     NSData *cacheData = data;
-    BOOL thumbnailed = context[SDWebImageContextImageThumbnailPixelSize];
+    BOOL thumbnailed = context[SDWebImageContextImageThumbnailPixelSize] != nil;
     if (thumbnailed) {
         // Thumbnail decoding already stored original data before in `storeCacheProcess`
         // Here we only store the thumbnail image to memory for thumbnail cache key

SDWebImage/Core/UIImage+Metadata.h

@@ -65,4 +65,9 @@
  */
 @property (nonatomic, assign) BOOL sd_isIncremental;
 
+/**
+ A bool value indicating whether the image is from thumbnail decoding and may be smaller than the full image data pixel size.
+ */
+@property (nonatomic, assign) BOOL sd_isThumbnail;
+
 @end

SDWebImage/Core/UIImage+Metadata.m

@@ -186,4 +186,13 @@
     return value.boolValue;
 }
 
+- (void)setSd_isThumbnail:(BOOL)sd_isThumbnail {
+    objc_setAssociatedObject(self, @selector(sd_isThumbnail), @(sd_isThumbnail), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
+- (BOOL)sd_isThumbnail {
+    NSNumber *value = objc_getAssociatedObject(self, @selector(sd_isThumbnail));
+    return value.boolValue;
+}
+
 @end

SDWebImage/Private/SDAssociatedObject.m

@@ -18,6 +18,7 @@ void SDImageCopyAssociatedObject(UIImage * _Nullable source, UIImage * _Nullable
     }
     // Image Metadata
     target.sd_isIncremental = source.sd_isIncremental;
+    target.sd_isThumbnail = source.sd_isThumbnail;
     target.sd_imageLoopCount = source.sd_imageLoopCount;
     target.sd_imageFormat = source.sd_imageFormat;
     // Force Decode