From 5875df6602db2fdb504bf92981523262bfb28cb3 Mon Sep 17 00:00:00 2001
From: jidicula <johanan@forcepush.tech>
Date: Mon, 4 Oct 2021 20:21:48 -0400
Subject: [PATCH] fix(array test): Fail with missing separator

The toml-test generated test for an array with missing separators was
failing since the parser wasn't noticing missing separators.

This change leverages the zero value of `ast.Reference` (an int). The
var is now declared outside the while block, and re-zeroed if the
token is not a non-trailing comma.

The parser checks if the previous value of `valueRef` is zero. The
only time this check would pass is when the previous byte in the array
was a whitespace, which would only be the case when an array is
missing a separator.

Resolves: part of pelletier/go-toml#613
---
 parser.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/parser.go b/parser.go
index b86904ae..00fca146 100644
--- a/parser.go
+++ b/parser.go
@@ -414,6 +414,7 @@ func (p *parser) parseValArray(b []byte) (ast.Reference, []byte, error) {
 
 	var lastChild ast.Reference
 
+	var valueRef ast.Reference
 	var err error
 	for len(b) > 0 {
 		b, err = p.parseOptionalWhitespaceCommentNewline(b)
@@ -439,6 +440,8 @@ func (p *parser) parseValArray(b []byte) (ast.Reference, []byte, error) {
 			if err != nil {
 				return parent, nil, err
 			}
+		} else {
+			valueRef = 0
 		}
 
 		// TOML allows trailing commas in arrays.
@@ -446,7 +449,9 @@ func (p *parser) parseValArray(b []byte) (ast.Reference, []byte, error) {
 			break
 		}
 
-		var valueRef ast.Reference
+		if !first && valueRef == 0 {
+			return parent, nil, newDecodeError(b[0:1], "array elements must be separated by commas")
+		}
 
 		valueRef, b, err = p.parseVal(b)
 		if err != nil {