format: exclude body on CaseClause len check

fixes #217

format/format.go

@@ -594,7 +594,13 @@ func (f *fumpter) applyPre(c *astutil.Cursor) {
 			// don't move comments
 			break
 		}
-		if f.printLength(node) > shortLineLimit {
+		// check the length excluding the body
+		nodeWithoutBody := &ast.CaseClause{
+			Case:  node.Case,
+			List:  node.List,
+			Colon: node.Colon,
+		}
+		if f.printLength(nodeWithoutBody) > shortLineLimit {
 			// too long to collapse
 			break
 		}

testdata/scripts/short-case.txt

@@ -50,6 +50,40 @@ func f(r rune) {
 		}
 	}
 }
+
+func s(x int) {
+	switch x {
+	case
+		shortConstant1,
+		shortConstant2:
+		// A comment.
+		fmt.Println(x)
+	case
+		shortConstant3,
+		shortConstant4:
+		// Do nothing.
+	default:
+		// Another comment.
+		fmt.Println(x * 2)
+	}
+}
+
+func s(x int) {
+	switch x {
+	case
+		longerConstantName1,
+		longerConstantName2:
+		// A comment.
+		fmt.Println(x)
+	case
+		longerConstantName3,
+		longerConstantName4:
+		// Do nothing.
+	default:
+		// Another comment.
+		fmt.Println(x * 2)
+	}
+}
 -- foo.go.golden --
 package p
 
@@ -91,3 +125,33 @@ func f(r rune) {
 		}
 	}
 }
+
+func s(x int) {
+	switch x {
+	case shortConstant1, shortConstant2:
+		// A comment.
+		fmt.Println(x)
+	case shortConstant3, shortConstant4:
+		// Do nothing.
+	default:
+		// Another comment.
+		fmt.Println(x * 2)
+	}
+}
+
+func s(x int) {
+	switch x {
+	case
+		longerConstantName1,
+		longerConstantName2:
+		// A comment.
+		fmt.Println(x)
+	case
+		longerConstantName3,
+		longerConstantName4:
+		// Do nothing.
+	default:
+		// Another comment.
+		fmt.Println(x * 2)
+	}
+}