cue/format: indent list elements correctly

Vertical tabs are used when printing some struct fields
for the sake of vertical alignment of the values.
This does not happen for fields where the value needs a form feed,
for the sake of not aligning every single struct field.
For example, we don't align those with struct and list values
since they tend to be complex or take multiple lines.

The logic to detect whether a field value needs a form feed was brittle
since it only looked for a struct or list directly in the expression,
entirely missing one if it was behind a unary or binary expression.
Fix up that logic and update the tests.

Fixes #2314.

Closes #2645 as merged as of commit cff4c1a.

Signed-off-by: Thomas Way <[email protected]>
Change-Id: Ie543e41ebf15d724632bc9a0dd1d9df28032ddc4
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1170966
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>
Reviewed-by: Paul Jolly <[email protected]>

cmd/cue/cmd/testdata/script/get_go_types.txtar

@@ -266,12 +266,12 @@ import (
 	Slice1: [...int] @go(,[]int)
 	Slice2: [...] @go(,[]interface{})
 	Slice3?: null | [...] @go(,*[]json.Unmarshaler)
-	Array1:  5 * [int]    @go(,[5]int)
-	Array2:  5 * [_]      @go(,[5]interface{})
+	Array1: 5 * [int] @go(,[5]int)
+	Array2: 5 * [_] @go(,[5]interface{})
 	Array3?: null | 5*[_] @go(,*[5]json.Marshaler)
-	Array4:  bytes        @go(,[5]byte)
-	Intf:    #Interface   @protobuf(2,varint,name=intf)
-	Intf2:   _            @go(,interface{})
+	Array4: bytes      @go(,[5]byte)
+	Intf:   #Interface @protobuf(2,varint,name=intf)
+	Intf2:  _          @go(,interface{})
 	Intf3: {
 		Interface: #Interface
 	} @go(,struct{Interface})

cue/format/node.go

@@ -431,6 +431,16 @@ func (f *formatter) nextNeedsFormfeed(n ast.Expr) bool {
 		return strings.IndexByte(x.Value, '\n') >= 0
 	case *ast.ListLit:
 		return true
+	case *ast.UnaryExpr:
+		return f.nextNeedsFormfeed(x.X)
+	case *ast.BinaryExpr:
+		return f.nextNeedsFormfeed(x.X) || f.nextNeedsFormfeed(x.Y)
+	case *ast.CallExpr:
+		for _, arg := range x.Args {
+			if f.nextNeedsFormfeed(arg) {
+				return true
+			}
+		}
 	}
 	return false
 }

cue/format/testdata/expressions.golden

@@ -1,5 +1,7 @@
 package expressions
 
+import "list"
+
 {
 	a:   1  // comment
 	aaa: 22 // comment
@@ -235,4 +237,20 @@ package expressions
 
 	"contains		tabs": 123
 	@jsonschema(foo="contains		tabs")
+
+	j: cueckoo: _ | [
+		1,
+
+		2,
+	]
+	k: cueckoo: *[
+		1,
+
+		2,
+	]
+	l: cueckoo: list.Concat([
+		1,
+
+		2,
+	])
 }

cue/format/testdata/expressions.input

@@ -1,11 +1,13 @@
 package expressions
 
+import "list"
+
 {
     a: 1 // comment
     aaa: 22 // comment
 
     "": 3
-    
+
     b: 3
 
     c: b: a:  4
@@ -171,7 +173,7 @@ package expressions
             "\(k)":v
         }
     }
-    
+
     e: { for k, v in someObject if k > "a" {"\(k)":v} }
     e: { for k, v in someObject if k > "a" {
         "\(k)":v }}
@@ -232,4 +234,20 @@ package expressions
 
     "contains		tabs": 123
     @jsonschema(foo="contains		tabs")
+
+    j: cueckoo: _ | [
+        1,
+
+        2,
+    ]
+    k: cueckoo: *[
+        1,
+
+        2,
+    ]
+    l: cueckoo: list.Concat([
+        1,
+
+        2,
+    ])
 }

encoding/jsonschema/testdata/list.txtar

@@ -40,6 +40,6 @@ import "list"
 
 foo?: [...string]
 tuple?: [string, int, 2]
-has?:  list.Contains(3)
+has?: list.Contains(3)
 size?: list.UniqueItems() & list.MaxItems(9) & [_, _, _, ...]
 additional?: [int, int, ...string]

encoding/jsonschema/testdata/type.txtar

@@ -32,7 +32,7 @@
 -- out.cue --
 // Main schema
 intString?: null | bool | int | string | [...]
-object?:    {
+object?: {
 	...
 } | *{
 	foo: "bar"

internal/core/export/testdata/main/adt.txtar

@@ -44,7 +44,7 @@ l5: [1, 3] & {
 }
 
 #foo: int
-l6:   [1, #foo] & {
+l6: [1, #foo] & {
 	[1, 3]
 
 	#foo: int
@@ -180,7 +180,7 @@ l5: [1, 3] & {
 	#foo: int
 }
 #foo: int
-l6:   [1, #foo] & {
+l6: [1, #foo] & {
 	[1, 3]
 	#foo: int
 }
@@ -197,7 +197,7 @@ e5:  e1 + e2 - e3
 e6:  !t
 e7:  !t || !false
 e8?: !false
-m1:  {
+m1: {
 	[string]: int & >=0
 } & {
 	{

pkg/list/testdata/list.txtar

@@ -168,7 +168,7 @@ unique: {
 // Issue #2099
 minItems: {
 	incomplete1: [...] & list.MinItems(1)
-	fail1:       _|_ // minItems.fail1: invalid value [] (does not satisfy list.MinItems(1)): len(list) < MinItems(1) (0 < 1) (and 1 more errors)
+	fail1: _|_ // minItems.fail1: invalid value [] (does not satisfy list.MinItems(1)): len(list) < MinItems(1) (0 < 1) (and 1 more errors)
 	ok1: [0, ...]
 	ok2: [0]
 }

pkg/struct/testdata/struct.txtar

@@ -36,7 +36,7 @@ import "struct"
 
 minFields: {
 	incomplete1: {} & struct.MinFields(1)
-	fail1:       _|_ // minFields.fail1: invalid value {} (does not satisfy struct.MinFields(1)): len(fields) < MinFields(1) (0 < 1)
+	fail1: _|_ // minFields.fail1: invalid value {} (does not satisfy struct.MinFields(1)): len(fields) < MinFields(1) (0 < 1)
 	ok1: {
 		a: 1
 	}