url is kind of NSString and shouldUseWeakMemoryCache is YES, APP will crash. (#3686)

* NSString will crash

* unit test

* unit test opt

---------

Co-authored-by: songjk <fusheng@douyu.tv>

SDWebImage/Core/UIView+WebCache.m

@@ -61,6 +61,18 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
                                                  setImageBlock:(nullable SDSetImageBlock)setImageBlock
                                                       progress:(nullable SDImageLoaderProgressBlock)progressBlock
                                                      completed:(nullable SDInternalCompletionBlock)completedBlock {
+    
+    // Very common mistake is to send the URL using NSString object instead of NSURL. For some strange reason, Xcode won't
+    // throw any warning for this type mismatch. Here we failsafe this error by allowing URLs to be passed as NSString.
+    //  if url is NSString and shouldUseWeakMemoryCache is true, [cacheKeyForURL:context] will crash. just for a  global protect.
+    if ([url isKindOfClass:NSString.class]) {
+        url = [NSURL URLWithString:(NSString *)url];
+    }
+    // Prevents app crashing on argument type error like sending NSNull instead of NSURL
+    if (![url isKindOfClass:NSURL.class]) {
+        url = nil;
+    }
+    
     if (context) {
         // copy to avoid mutable object
         context = [context copy];

Tests/Tests/SDWebCacheCategoriesTests.m

@@ -620,6 +620,52 @@
     [self waitForExpectationsWithCommonTimeout];
 }
 
+// test url is nil
+- (void)testUIViewImageUrlForNilWorks {
+    XCTestExpectation *expectation = [self expectationWithDescription:@"Completion is called with url is nil"];
+    UIImageView *imageView = [[UIImageView alloc] init];
+    SDImageCache *cache = [[SDImageCache alloc] initWithNamespace:@"Test"];
+    cache.config.shouldUseWeakMemoryCache = YES;
+    SDWebImageManager *imageManager = [[SDWebImageManager alloc] initWithCache:cache loader:[SDWebImageDownloader sharedDownloader]];
+    [imageView sd_setImageWithURL:nil placeholderImage:nil options:0 context:@{SDWebImageContextCustomManager:imageManager} progress:nil completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
+        expect(image).to.beNil();
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithCommonTimeout];
+    
+}
+
+// test url is NSString.
+- (void)testUIViewImageUrlForStringWorks {
+
+    XCTestExpectation *expectation = [self expectationWithDescription:@"Completion is called with url is NSString"];
+    
+    UIImageView *imageView = [[UIImageView alloc] init];
+    SDImageCache *cache = [[SDImageCache alloc] initWithNamespace:@"Test"];
+    cache.config.shouldUseWeakMemoryCache = YES;
+    SDWebImageManager *imageManager = [[SDWebImageManager alloc] initWithCache:cache loader:[SDWebImageDownloader sharedDownloader]];
+    [imageView sd_setImageWithURL:kTestJPEGURL placeholderImage:nil options:0 context:@{SDWebImageContextCustomManager:imageManager} progress:nil completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
+        expect(image).notTo.beNil();
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithCommonTimeout];
+}
+
+// test url is NSURL
+- (void)testUIViewImageUrlForNSURLWorks {
+    XCTestExpectation *expectation = [self expectationWithDescription:@"Completion is called with url is NSURL"];
+    UIImageView *imageView = [[UIImageView alloc] init];
+    SDImageCache *cache = [[SDImageCache alloc] initWithNamespace:@"Test"];
+    cache.config.shouldUseWeakMemoryCache = YES;
+    SDWebImageManager *imageManager = [[SDWebImageManager alloc] initWithCache:cache loader:[SDWebImageDownloader sharedDownloader]];
+    [imageView sd_setImageWithURL:[NSURL URLWithString:kTestJPEGURL] placeholderImage:nil options:0 context:@{SDWebImageContextCustomManager:imageManager} progress:nil completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
+        expect(image).notTo.beNil();
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithCommonTimeout];
+    
+}
+
 #pragma mark - Helper
 
 - (NSString *)testJPEGPath {