KFImage won't load image if EmptyView is a placeholder

[damian-rzeszot]

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Issue Description

What

The view I work with is quite complicated, but the whole problem comes down to this:

KFImage(url)
    .placeholder {
        EmptyView()
    }

This placeholder is used here and wrapped with a Group. For the Group only with EmptyView a callback for onAppear won't be called. This causes the image to not be loaded.

Other Comment

Sample code of onAppear behaviour

struct ContentView: View {
    var body: some View {
        Group {
            Color.clear
                .onAppear {
                    print("color clear in group ✅")
                }
            EmptyView()
                .onAppear {
                    print("empty view in group 🔴")
                }
        }
        .onAppear {
            print("group ✅")
        }

        Group {
            EmptyView()
                .onAppear {
                    print("empty view in group 🔴")
                }
        }
        .onAppear {
            print("group 🔴")
        }
    }
}

[onevcat]

@damian-rzeszot Nice catch and thank you for reporting this. Does #1973 (the fix/empty-placeholder-loading branch) work for you?

[damian-rzeszot]

Yes, it works great. Thanks for this quick fix

[onevcat]

After some checking, the same "issue" also happens in SwiftUI's AsyncImage. As Apple mentions in its documentation of EmptyView:

You will rarely, if ever, need to create an EmptyView directly. Instead, EmptyView represents the absence of a view.

I am now wondering if it is a bit anti-pattern to use an EmptyView as the placeholder.

A new PR #1975 was created to fix some broken layout behavior introduced in #1973, while keeping the ability of trigering a loading by EmptyView placeholder. However, I am still suggesting not to use that and maybe try to have a Color.clear placeholder instead.

[drspoton]

In my case I got EmptyView from optional Image