Fix C# tool script displaying exported variables in the wrong order

[devin-liang]

Hello all, first time contributor here :)

Previously, exported variables in a C# tool script would not appear in
the order they were exported within the inspector upon rebuilding the
project solution. The potential cause of this problem is that the
CSharpInstance::get_property_list method was iterating through
the member_info Map member variable to populate the p_properties
list argument.

Maps typically do not give guarantees about the ordering of elements
and I think that Godot's implementation of Map may also shuffle elements
around.

My proposed solution is to add a new list within the CSharpScript
class that contains the keys of the member_info Map in the order
they were inserted. This list is cleared and gets new elements
whenever the member_info Map is cleared or updated.

This fix causes exported variables in C# tools scripts to appear
in the order they were exported within the inspector after rebuilding
the project solution just like regular C# scripts.

Fixes #47465

[akien-mga]

Thanks for the contribution :) I'll let @neikeq review the implementation for Mono specifically.

Some meta comments:

• The bug likely exists in the master branch too, so that's where it should be fixed in priority. Otherwise if we merge this in 3.x only, it will be fixed in 3.4 but not in 4.0 and beyond.
• The email used to author your commit is not linked to your GitHub account, which is why the commit doesn't show as authored by "@devin-liang". That's not a problem for Git nor Godot, but if you want to "claim" this commit as being authored by your account, you can add this email as secondary email in your GitHub profile.

[devin-liang]

Thanks for the kind words and fast comment! The email tip is much appreciated.

[aaronfranke]

@devin-liang Any update? There still needs to be a version of this PR for the master branch.

[neikeq]

Maybe this should be done similarly to how GDScript does it:

godot/modules/gdscript/gdscript.cpp

Lines 1429 to 1442 in 6609ce1

	Vector<_GDScriptMemberSort> msort;
	for (Map<StringName, PropertyInfo>::Element *F = sptr->member_info.front(); F; F = F->next()) {
	_GDScriptMemberSort ms;
	ERR_CONTINUE(!sptr->member_indices.has(F->key()));
	ms.index = sptr->member_indices[F->key()].index;
	ms.name = F->key();
	msort.push_back(ms);
	}
	msort.sort();
	msort.reverse();
	for (int i = 0; i < msort.size(); i++) {
	props.push_front(sptr->member_info[msort[i].name]);
	}

[akien-mga]

Closing as this needs to be redone as advised above. Marking as salvageable.

[raulsntos]

@neikeq It seems what GDScript does is simply sort the properties by their index which they keep in a different Map, how is that different from what devin-liang was trying to do but instead of keeping the index information in a Map he was using a List, maybe we should replace member_info with an OrderedHashMap which is basically a Map like before but it already includes that List with the order inside so they don't go out of sync.

@devin-liang Are you still working on this? If not, would you mind if I give it a try?

[devin-liang]

@raulsntos Yeah go ahead and give it try if you'd like. I don't think I'll be actively working on this anymore. I apologize for no updates on this issue for so long.

[raulsntos]

Opened #54130 for master and #54199 for 3.x