[3.x] Fix inner class parsing when statement after colon is on the same line (reverted)

[kdiduk]

This commit fixes #56703

The fix is to increase indent level when the statement after the colon token is on the same line.

It looks like this issue is a regression introduced after some of the changes. Because in one of the earlier versions of that piece of code the intend level was increased (see this, for example).

Bugsquad edit:

• Fix GDScript: empty class definition leads to error somewhere else #56703

[kdiduk]

If this PR is approved and merged, we need to update documentation for GDScript grammar (both in 3.x and 4.0), because it says that after the colon in the inner class declaration there is a newline:

innerClass = "class" IDENTIFIER [ inheritance ] ":" NEWLINE
    INDENT [ inheritance NEWLINE ] topLevelDecl { topLevelDecl } DEDENT ;

As I understand, the idea is to have it more Python'ic way, where this is allowed:

class Foo: pass

At least in 4.0 it already works like that.

[akien-mga]

It looks like this issue is a regression introduced after some of the changes. Because in one of the earlier versions of that piece of code the intend level was increased (see this, for example).

For the record, the +1 was removed in this PR: #8123.
And that code was further refactored in #32808.

Please make sure that this doesn't reintroduce the issues that those PRs fixed.

[kdiduk]

Please make sure that this doesn't reintroduce the issues that those PRs fixed.

@akien-mga Thank you for mentioning the original PR! Indeed my initial fix re-introduced some issues from them.

I've just pushed another implementation. I've implemented a special case for inner classes and it doesn't touch the cases mentioned in those PRs.

In this implementation, it's allowed to write like this:

class Foo: pass

And also, as in Python, it's not allowed to use anything else apart from pass in one-liner class, like that:

class Foo: func bar(): pass

Some of the test-cases that I've used can be found here:

test_inner_classes.gd

extends Node2D

class Foo: 
	func foo():
		return "Hello, Foo!"

class Bar extends Foo: pass # inner class

# not allowed: says "unexpected indentation"
# class BadBar: pass
# 	func bad_bar():
# 		pass

class FooBar extends Bar:
	func foo():
		return "Hello, FooBar!"

var foo_var: FooBar = FooBar.new()

class AnotherInnerClass:
	func foo(): pass


func _ready(): $RichTextLabel.text = foo_var.foo()

# at the end of file
class BarFoo extends Foo: pass

I can also do some refactoring to clean up and eliminate duplicated code.

[vnen]

Looks good to me, my remarks are only about the comment formatting.

[kdiduk]

@vnen Thank you for your remarks. I've just pushed new changes with some refactoring. I have eliminated duplicated code blocks, extracting it into separate methods. Could you review it again?

[vnen]

Looks good to me, just have one style remark.

[vnen]

Looks good to me

[kdiduk]

FYI: this pull-request is in the milestone 3.x, although the bug that it fixes #56703 is in the milestone 3.5. I guess the both should be in the same milestone.

[akien-mga]

Thanks!