Merge pull request #181 from hashicorp/b-heredoc-single

hcl: print single heredoc elements properly

hcl/printer/nodes.go

@@ -474,6 +474,13 @@ func (p *printer) list(l *ast.ListType) []byte {
 	insertSpaceBeforeItem := false
 	lastHadLeadComment := false
 	for i, item := range l.List {
+		// Keep track of whether this item is a heredoc since that has
+		// unique behavior.
+		heredoc := false
+		if lit, ok := item.(*ast.LiteralType); ok && lit.Token.Type == token.HEREDOC {
+			heredoc = true
+		}
+
 		if item.Pos().Line != l.Lbrack.Line {
 			// multiline list, add newline before we add each item
 			buf.WriteByte(newline)
@@ -507,7 +514,7 @@ func (p *printer) list(l *ast.ListType) []byte {
 			// if this item is a heredoc, then we output the comma on
 			// the next line. This is the only case this happens.
 			comma := []byte{','}
-			if lit, ok := item.(*ast.LiteralType); ok && lit.Token.Type == token.HEREDOC {
+			if heredoc {
 				buf.WriteByte(newline)
 				comma = p.indent(comma)
 			}
@@ -541,7 +548,17 @@ func (p *printer) list(l *ast.ListType) []byte {
 				buf.WriteByte(blank)
 				insertSpaceBeforeItem = false
 			}
+
+			// Output the item itself
 			buf.Write(p.output(item))
+
+			// If this is a heredoc item we always have to output a newline
+			// so that it parses properly.
+			if heredoc {
+				buf.WriteByte(newline)
+			}
+
+			// If this isn't the last element, write a comma.
 			if i != len(l.List)-1 {
 				buf.WriteString(",")
 				insertSpaceBeforeItem = true

hcl/printer/printer_test.go

@@ -42,6 +42,7 @@ var data = []entry{
 	{"empty_block.input", "empty_block.golden"},
 	{"list_of_objects.input", "list_of_objects.golden"},
 	{"multiline_string.input", "multiline_string.golden"},
+	{"object_with_heredoc.input", "object_with_heredoc.golden"},
 }
 
 func TestFiles(t *testing.T) {

hcl/printer/testdata/list.golden

@@ -37,9 +37,7 @@ EOS
   ,
 ]
 
-foo = [
-  <<EOS
+foo = [<<EOS
 one
 EOS
-  ,
 ]

hcl/printer/testdata/list.input

@@ -31,8 +31,7 @@ EOS
 ,
     ]
 
-foo = [
-    <<EOS
+foo = [<<EOS
 one
 EOS
     ]

hcl/printer/testdata/object_with_heredoc.golden

@@ -0,0 +1,6 @@
+obj {
+  foo = [<<EOF
+        TEXT!
+EOF
+  ]
+}

hcl/printer/testdata/object_with_heredoc.input

@@ -0,0 +1,6 @@
+obj {
+    foo = [<<EOF
+        TEXT!
+EOF
+    ]
+}