[pigeon] Support data class inheritance #117819
Description
For macOS file_selector I wanted to define panel options that followed the macOS panel class structure, which is that NSOpenPanel is an NSSavePanel so inherits its properties. I tried:
class SavePanelOptions {
SavePanelOptions({
this.directoryPath,
this.nameFieldStringValue,
this.prompt,
});
String? directoryPath;
String? nameFieldStringValue;
String? prompt;
}
class OpenPanelOptions extends SavePanelOptions {
OpenPanelOptions({
super.directoryPath,
super.nameFieldStringValue,
super.prompt,
this.allowsMultipleSelection = false,
this.canChooseDirectories = false,
this.canChooseFiles = true,
});
bool allowsMultipleSelection;
bool canChooseDirectories;
bool canChooseFiles;
}
The resulting output only has the direct properties though, not the inherited properties. For instance, the Dart is:
class SavePanelOptions {
SavePanelOptions({
this.directoryPath,
this.nameFieldStringValue,
this.prompt,
});
String? directoryPath;
String? nameFieldStringValue;
String? prompt;
Object encode() {...}
static SavePanelOptions decode(Object result) {...}
}
class OpenPanelOptions {
OpenPanelOptions({
required this.allowsMultipleSelection,
required this.canChooseDirectories,
required this.canChooseFiles,
});
bool allowsMultipleSelection;
bool canChooseDirectories;
bool canChooseFiles;
Object encode() {...}
static OpenPanelOptions decode(Object result) {...}
}
I can work around it by using composition instead of inheritance but it makes it more clunky to use on both sides.