preserve multiline single-entry iterables

v1/format/format.go

@@ -1869,20 +1869,30 @@ func (w *writer) writeIterable(elements []any, last *ast.Location, close *ast.Lo
 		return nil, err
 	}
 
-	// If there are comments within the single line, don't collapse it and keep it as-is
-	// Return an error so that writeTerm will write the original formatting
-	if len(lines) == 1 {
+	isOneLine := len(lines) == 1
+	isNonEmptyMultilineSource := len(elements) > 0 && close.Row > last.Row
+	hasBoundaryComment := false
+	if isOneLine && isNonEmptyMultilineSource {
+		if w.beforeEnd != nil {
+			row := w.beforeEnd.Location.Row
+			hasBoundaryComment = row >= last.Row && row <= close.Row
+		}
 		for _, c := range comments {
-			if c.Location.Row > last.Row && c.Location.Row < close.Row {
+			row := c.Location.Row
+			if row > last.Row && row < close.Row {
 				return comments, unexpectedCommentError{
 					newComment:    truncatedString(c.String(), 100),
 					newCommentRow: c.Location.Row,
 				}
 			}
+			if row == last.Row || row == close.Row {
+				hasBoundaryComment = true
+			}
 		}
 	}
 
-	if len(lines) > 1 {
+	isMultiline := len(lines) > 1 || (isOneLine && isNonEmptyMultilineSource && !hasBoundaryComment)
+	if isMultiline {
 		w.delayBeforeEnd()
 		w.startMultilineSeq()
 	}
@@ -1904,7 +1914,7 @@ func (w *writer) writeIterable(elements []any, last *ast.Location, close *ast.Lo
 		return nil, err
 	}
 
-	if len(lines) > 1 {
+	if isMultiline {
 		w.write(",")
 		w.endLine()
 		comments, err = w.insertComments(comments, close)

v1/format/testfiles/v0/test.rego.formatted

@@ -44,9 +44,15 @@ r = y {
 # Comment on else
 else = y {
 	y = ["howdy"]
-	x = {"x": {"y": "z"}}
+	x = {
+		"x": {
+			"y": "z",
+		},
+	}
 	a = {
-		"a": {"b": "c"},
+		"a": {
+			"b": "c",
+		},
 		"b": "c", "c": [
 			1, 2,
 			3, 4,
@@ -231,11 +237,15 @@ union_list := [(declare3 | declare4)]
 
 union_set_2 := {(declare3 | declare4)}
 
-union_object_multi_line := {"response": (declare3 | declare4)}
+union_object_multi_line := {
+	"response": (declare3 | declare4),
+}
 
 union_object_key := {(declare3 | declare4): "foo"}
 
-union_object_key_multi_line := {(declare3 | declare4): "foo"}
+union_object_key_multi_line := {
+	(declare3 | declare4): "foo",
+}
 
 # more comments!
 # more comments!

v1/format/testfiles/v0/test_issue_6330.rego.formatted

@@ -1,20 +1,38 @@
 package a
 
-value := {"a": {"b": {"c": "d"}}}
+value := {
+	"a": {
+		"b": {
+			"c": "d",
+		},
+	},
+}
 
 value := {"a":  # test 1
 "b"} # test 2
 
 value := {"a": "b"} # test 1
 
-value := {"a": {"b": {"c": "d"}}}
+value := {
+	"a": {
+		"b": {
+			"c": "d",
+		},
+	},
+}
 
 value := {"a": # this is
 {"b": # my ridiculous
 {"c": # way of
 "d"}}} # commenting code
 
-value := {"a": {"b": {"c": "d"}}}
+value := {
+	"a": {
+		"b": {
+			"c": "d",
+		},
+	},
+}
 
 p[{"a": #
 "b"} #

v1/format/testfiles/v0/test_with.rego.formatted

@@ -7,7 +7,9 @@ single_line_with {
 multi_line_with {
 	fn(1) with input.a as "a"
 		with input.b as "b"
-		with input.c as {"foo": "bar"}
+		with input.c as {
+			"foo": "bar",
+		}
 		with input.d as [
 			1,
 			2,

v1/format/testfiles/v1/test.rego.formatted

@@ -41,9 +41,15 @@ r := y if {
 # Comment on else
 else := y if {
 	y = ["howdy"]
-	x = {"x": {"y": "z"}}
+	x = {
+		"x": {
+			"y": "z",
+		},
+	}
 	a = {
-		"a": {"b": "c"},
+		"a": {
+			"b": "c",
+		},
 		"b": "c", "c": [
 			1, 2,
 			3, 4,
@@ -222,11 +228,15 @@ union_list := [(declare3 | declare4)]
 
 union_set_2 := {(declare3 | declare4)}
 
-union_object_multi_line := {"response": (declare3 | declare4)}
+union_object_multi_line := {
+	"response": (declare3 | declare4),
+}
 
 union_object_key := {(declare3 | declare4): "foo"}
 
-union_object_key_multi_line := {(declare3 | declare4): "foo"}
+union_object_key_multi_line := {
+	(declare3 | declare4): "foo",
+}
 
 # more comments!
 # more comments!

v1/format/testfiles/v1/test_issue_6330.rego.formatted

@@ -4,14 +4,26 @@ p[{"a": #
 "b"} #
 ] := true
 
-value := {"a": {"b": {"c": "d"}}}
+value := {
+	"a": {
+		"b": {
+			"c": "d",
+		},
+	},
+}
 
 value := {"a":  # test 1
 "b"} # test 2
 
 value := {"a": "b"} # test 1
 
-value := {"a": {"b": {"c": "d"}}}
+value := {
+	"a": {
+		"b": {
+			"c": "d",
+		},
+	},
+}
 
 value := {"a": # this is
 {"b": # my ridiculous
@@ -23,7 +35,13 @@ p := {"a":  #
 	str := "my \n string"
 }
 
-value := {"a": {"b": {"c": "d"}}}
+value := {
+	"a": {
+		"b": {
+			"c": "d",
+		},
+	},
+}
 
 f(_) := value if {
 	value := {"a": # this is
@@ -63,7 +81,9 @@ p := {"a": str} if { #
 	str := "my \n string"
 }
 
-p := {"a": str} if {
+p := {
+	"a": str,
+} if {
 	#
 	str := "my \n string"
 }

v1/format/testfiles/v1/test_issue_8557.rego

@@ -0,0 +1,19 @@
+package test
+
+test_with_and_indentation if {
+	my_mock_object := {
+		"the_first_key": {
+			"a_nested_key": {
+				"and_sub_nested_key": [
+					{
+						"yet_another_key": [
+							"and_sub_nested_key_value", "foooo", "baaar",
+						],
+					},
+				],
+			}
+		}
+	}
+
+	_ = my_mock_object
+}

v1/format/testfiles/v1/test_issue_8557.rego.formatted

@@ -0,0 +1,19 @@
+package test
+
+test_with_and_indentation if {
+	my_mock_object := {
+		"the_first_key": {
+			"a_nested_key": {
+				"and_sub_nested_key": [
+					{
+						"yet_another_key": [
+							"and_sub_nested_key_value", "foooo", "baaar",
+						],
+					},
+				],
+			},
+		},
+	}
+
+	_ = my_mock_object
+}

v1/format/testfiles/v1/test_with.rego.formatted

@@ -7,7 +7,9 @@ single_line_with if {
 multi_line_with if {
 	fn(1) with input.a as "a"
 		with input.b as "b"
-		with input.c as {"foo": "bar"}
+		with input.c as {
+			"foo": "bar",
+		}
 		with input.d as [
 			1,
 			2,