Avoid breaking dot chains containing a lambda(s), fixes #326

Author: Scony

CHANGELOG.md

@@ -10,6 +10,7 @@
  - Fixed support for `get_node` syntax to accommodate for `$/(...)`
  - Changed formatting of some uni-statement lambdas
  - Changed formatting of multi-statement, inline lambdas
+ - Changed formatting of dot-chains containing a lambda(s)
 
 ## [4.3.1] 2024-08-24
 

gdtoolkit/formatter/expression.py

@@ -12,6 +12,7 @@
     remove_outer_parentheses,
     is_foldable,
     is_expression_forcing_multiple_lines,
+    expression_contains_lambda,
     is_any_comma,
     is_trailing_comma,
 )
@@ -716,6 +717,12 @@ def _format_dot_chain_to_multiple_lines(
     expression_context: ExpressionContext,
     context: Context,
 ) -> FormattedLines:
+    # temporary workaround for likely Godot bug
+    # TODO: remove once not needed anymore (this probably should be kept until Godot 5 for compat)
+    if expression_contains_lambda(dot_chain):
+        return _format_dot_chain_to_multiple_lines_bottom_up(
+            dot_chain, expression_context, context
+        )
     if is_expression_forcing_multiple_lines(dot_chain, context.standalone_comments):
         return _format_operator_chain_based_expression_to_multiple_lines(
             dot_chain, expression_context, context

gdtoolkit/formatter/expression_utils.py

@@ -63,6 +63,17 @@ def is_expression_forcing_multiple_lines(
     return False
 
 
+def expression_contains_lambda(expression: Node):
+    if isinstance(expression, Token):
+        return False
+    if expression.data == "lambda":
+        return True
+    for child in expression.children:
+        if expression_contains_lambda(child):
+            return True
+    return False
+
+
 def is_any_comma(expression: Node) -> bool:
     return (isinstance(expression, Tree) and expression.data == "trailing_comma") or (
         isinstance(expression, Token) and expression.type == "COMMA"

tests/formatter/input-output-pairs/bug_326_multistatement_lambda_corner_case_workaround.in.gd

@@ -0,0 +1,18 @@
+extends Node
+
+func _ready() -> void:
+	get_tree().create_timer(1.0).timeout.connect(
+		func():
+			print("Hello world!")
+			print("This is a bug test.")
+	)
+func foo():
+	get_tree().create_timer(1.0).timeout.connect(
+		func():
+			print("Hello world!")
+			return [1,]
+	)
+func bar():
+	get_tree().create_timer(1.0).timeout.connect(func(): return [1,])
+func baz(x):
+	x.aaaaaaaaaaaaa.bbbbbbbbbbbb.cccccccccccccc.dddddddddddddd.eeeeeeeeeeeeee.fffffffffffff.ggggggggggggg.hhhhh(func(): return 1)

tests/formatter/input-output-pairs/bug_326_multistatement_lambda_corner_case_workaround.out.gd

@@ -0,0 +1,34 @@
+extends Node
+
+
+func _ready() -> void:
+	get_tree().create_timer(1.0).timeout.connect(
+		func():
+			print("Hello world!")
+			print("This is a bug test.")
+	)
+
+
+func foo():
+	get_tree().create_timer(1.0).timeout.connect(
+		func():
+			print("Hello world!")
+			return [
+				1,
+			]
+	)
+
+
+func bar():
+	get_tree().create_timer(1.0).timeout.connect(
+		func():
+			return [
+				1,
+			]
+	)
+
+
+func baz(x):
+	x.aaaaaaaaaaaaa.bbbbbbbbbbbb.cccccccccccccc.dddddddddddddd.eeeeeeeeeeeeee.fffffffffffff.ggggggggggggg.hhhhh(
+		func(): return 1
+	)

tests/potential-godot-bugs/lambda_corner_case.gd

@@ -0,0 +1,49 @@
+extends Node
+
+func foo():
+	pass
+
+func _ready() -> void:
+	get_tree().create_timer(1.0).timeout.connect(foo)  # works
+	get_tree().create_timer(1.0).timeout.connect(func(): foo())  # works
+	get_tree().create_timer(1.0).timeout.connect(
+		func():
+		foo()
+	)  # works
+	(
+		get_tree()
+		. create_timer(1.0)
+		. timeout
+		. connect(foo)
+	)  # works
+	(
+		get_tree()
+		. create_timer(1.0)
+		. timeout
+		. connect(func(): foo())
+	)  # works
+	(
+		get_tree()
+		. create_timer(1.0)
+		. timeout
+		. connect(
+			func(): foo()
+		)
+	)  # works
+	(
+		get_tree()
+		. create_timer(1.0)
+		. timeout
+		. connect(
+			func():
+				foo())
+	)  # works !
+	(
+		get_tree()
+		. create_timer(1.0)
+		. timeout
+		. connect(
+			func():
+				foo()
+		)
+	)  # doesn't work !