From 3b91ad576431d48f3be01ca6af67e0d45d123538 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Tue, 20 Jul 2021 11:01:56 +1000
Subject: [PATCH] Handle leading comment with no new-line

---
 acceptance_tests/empty.sh | 20 ++++++++++++++++++++
 pkg/yqlib/printer.go      |  6 ++++++
 2 files changed, 26 insertions(+)

diff --git a/acceptance_tests/empty.sh b/acceptance_tests/empty.sh
index a88a6f4b..d7f344df 100755
--- a/acceptance_tests/empty.sh
+++ b/acceptance_tests/empty.sh
@@ -8,7 +8,27 @@ EOL
 
 testEmptyEval() {
   X=$(./yq e test.yml)
+  expected=$(cat test.yml)
   assertEquals 0 $?
+  assertEquals "$expected" "$X"
+}
+
+testEmptyEvalNoNewLine() {
+  echo -n "#comment" >test.yml
+  X=$(./yq e test.yml)
+  expected=$(cat test.yml)
+  assertEquals 0 $?
+  assertEquals "$expected" "$X"
+}
+
+testEmptyEvalNoNewLineWithExpression() {
+  echo -n "# comment" >test.yml
+  X=$(./yq e '.apple = "tree"' test.yml)
+  read -r -d '' expected << EOM
+# comment
+apple: tree
+EOM
+  assertEquals "$expected" "$X"
 }
 
 testEmptyEvalPipe() {
diff --git a/pkg/yqlib/printer.go b/pkg/yqlib/printer.go
index 64c477d6..89a0bec9 100644
--- a/pkg/yqlib/printer.go
+++ b/pkg/yqlib/printer.go
@@ -147,6 +147,12 @@ func (p *resultsPrinter) PrintResults(matchingNodes *list.List) error {
 				}
 
 				if errReading == io.EOF {
+					if readline != "" {
+						// the last comment we read didn't have a new line, put one in
+						if err := p.writeString(bufferedWriter, "\n"); err != nil {
+							return err
+						}
+					}
 					break
 				}
 			}