From 719c56221943db51502eae283626bb25e0cce4c8 Mon Sep 17 00:00:00 2001
From: Waldemar Quevedo <wally@nats.io>
Date: Fri, 28 Jul 2023 15:46:11 -0700
Subject: [PATCH] config: make parsing configurations without usable values
 invalid

This makes configuration files that are empty, or read and processed
by the parser but with no detected values now return an error.

Signed-off-by: Waldemar Quevedo <wally@nats.io>
---
 conf/parse.go      |  4 +++-
 conf/parse_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/conf/parse.go b/conf/parse.go
index 612b16438e9..4d2a20adeed 100644
--- a/conf/parse.go
+++ b/conf/parse.go
@@ -146,7 +146,9 @@ func parse(data, fp string, pedantic bool) (p *parser, err error) {
 			return nil, err
 		}
 	}
-
+	if len(p.mapping) == 0 {
+		return nil, fmt.Errorf("config has no values or is empty")
+	}
 	return p, nil
 }
 
diff --git a/conf/parse_test.go b/conf/parse_test.go
index 4c8c07fbb3a..3fc7c9275f8 100644
--- a/conf/parse_test.go
+++ b/conf/parse_test.go
@@ -403,3 +403,30 @@ func TestParserNoInfiniteLoop(t *testing.T) {
 		}
 	}
 }
+
+func TestParseWithNoValues(t *testing.T) {
+	for _, test := range []string{
+		``,
+		`aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		`              aaaaaaaaaaaaaaaaaaaaaaaaaaa`,
+		`     aaaaaaaaaaaaaaaaaaaaaaaaaaa         `,
+		`
+                # just comments with no values
+                # is also invalid.
+                `,
+		`
+                # with comments and no spaces to create key values
+                # is also an invalid config.
+                aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+                `,
+		`
+                a,a,a,a,a,a,a,a,a,a,a
+                `,
+	} {
+		if _, err := parse(test, "", true); err == nil {
+			t.Fatal("expected an error")
+		} else if !strings.Contains(err.Error(), "config has no values or is empty") {
+			t.Fatal("expected invalid conf error")
+		}
+	}
+}