Use Fluttered structured error events (behind preview flag)

[DanTup]

@jacob314 @InMatrix @devoncarew I've made some progress on this, trying to make them look like IntelliJ's (so please let me know if they change - for ex the yellow ascii banner - so I can copy).

Two of the examples in @InMatrix's repo don't look too bad:

However the Material one looks really bad:

I think probably I'm rendering more nodes than I should (though it's not clear how I should decide which to show), but also some of it's just in the source (like the top line is like this in one big string). How should that be handled?

• Also needs tests

[DanTup]

Also, there seems to be a race at startup - if an error occurs in startup code, it may be before structuredErrors has been toggled on. As far as I can tell, the service extension doesn't load until after I resumed the isolate, so I don't know if there's a way to avoid this?

[devoncarew]

Some drive-by-comments:

• we'll need to adjust the ◢◤◢◤◢◤◢◤◢◤◢◤ chars (used by IntelliJ as well) to some other ansi chars; doesn't have to be for this PRR, but those chars are used by Flutter to signify layout overflow
• after a summary line, you'll want to output a single blank line
• IntelliJ is currently not printing out nodes where type == ErrorSpacer
• we don't recurse into child nodes if style == shallow (we still show local properties)

The impl. for IntelliJ is all at https://github.com/flutter/flutter-intellij/blob/master/src/io/flutter/logging/FlutterConsoleLogManager.java#L135.

[devoncarew]

As far as I can tell, the service extension doesn't load until after I resumed the isolate, so I don't know if there's a way to avoid this?

I've seen this race as well, but don't have a good solution.

[DanTup]

Thanks for the notes! I had been following the IntelliJ implementation but I couldn't figure out all the differences (I suck at reading Java :-)).

I'll make those changes - and I'll update the banner to match whatever you do in IntelliJ once you've made a decision about what to do there.

[FrobtheBuilder]

Oh my god, thank you, it was so utterly aggravating to have the console filled up with literally hundreds of lines of calls you don't care about.