From 3af15c0725605162dc8dad0c6ab241e2dc4553c6 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Tue, 16 Jun 2020 12:02:23 -0600
Subject: [PATCH] caddyhttp: Empty, not nil, query matcher matches empty query
 string

---
 modules/caddyhttp/matchers.go      | 13 +++++--------
 modules/caddyhttp/matchers_test.go |  8 ++++----
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index 6662daca..a291242a 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -349,6 +349,9 @@ func (MatchQuery) CaddyModule() caddy.ModuleInfo {
 
 // UnmarshalCaddyfile implements caddyfile.Unmarshaler.
 func (m *MatchQuery) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	if *m == nil {
+		*m = make(map[string][]string)
+	}
 	for d.Next() {
 		var query string
 		if !d.Args(&query) {
@@ -361,9 +364,6 @@ func (m *MatchQuery) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 		if len(parts) != 2 {
 			return d.Errf("malformed query matcher token: %s; must be in param=val format", d.Val())
 		}
-		if *m == nil {
-			*m = make(map[string][]string)
-		}
 		url.Values(*m).Set(parts[0], parts[1])
 		if d.NextBlock(0) {
 			return d.Err("malformed query matcher: blocks are not supported")
@@ -372,11 +372,8 @@ func (m *MatchQuery) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 	return nil
 }
 
-// Match returns true if r matches m.
+// Match returns true if r matches m. An empty m matches an empty query string.
 func (m MatchQuery) Match(r *http.Request) bool {
-	if m == nil {
-		return len(r.URL.Query()) == 0
-	}
 	for param, vals := range m {
 		paramVal, found := r.URL.Query()[param]
 		if found {
@@ -387,7 +384,7 @@ func (m MatchQuery) Match(r *http.Request) bool {
 			}
 		}
 	}
-	return false
+	return len(m) == 0 && len(r.URL.Query()) == 0
 }
 
 // CaddyModule returns the Caddy module information.
diff --git a/modules/caddyhttp/matchers_test.go b/modules/caddyhttp/matchers_test.go
index 219ada88..1ac95882 100644
--- a/modules/caddyhttp/matchers_test.go
+++ b/modules/caddyhttp/matchers_test.go
@@ -529,20 +529,20 @@ func TestQueryMatcher(t *testing.T) {
 			expect:   false,
 		},
 		{
-			scenario: "nil matcher value should match empty query",
-			match:    MatchQuery(nil),
+			scenario: "empty matcher value should match empty query",
+			match:    MatchQuery{},
 			input:    "/?",
 			expect:   true,
 		},
 		{
 			scenario: "nil matcher value should NOT match a non-empty query",
-			match:    MatchQuery(nil),
+			match:    MatchQuery{},
 			input:    "/?foo=bar",
 			expect:   false,
 		},
 		{
 			scenario: "non-nil matcher should NOT match an empty query",
-			match:    MatchQuery{"": []string{}},
+			match:    MatchQuery{"": nil},
 			input:    "/?",
 			expect:   false,
 		},