pgconn: fix parseKeywordValueSettings rejecting trailing whitespace

The key-value connection string parser failed with "invalid keyword/value"
whenever the string ended with more than one space, or when a quoted value
was followed by any trailing spaces. This is because after consuming each
value the code only stripped a single byte (s[end+1:]), leaving extra
leading whitespace that caused the next loop iteration to see a partial
string without an '=' character.

Fix by trimming all leading whitespace from the remainder of the string
after consuming each value (unquoted and quoted), and also trimming the
string once before entering the loop. This matches libpq's behaviour,
which accepts any amount of whitespace between and after key-value pairs.

Fixes #2284

Signed-off-by: alliasgher <alliasgher123@gmail.com>

Author: alliasgher

pgconn/config.go

@@ -631,6 +631,9 @@ func parseKeywordValueSettings(s string) (map[string]string, error) {
 		"dbname": "database",
 	}
 
+	// Trim any leading whitespace so that the loop exits cleanly when only
+	// spaces remain (e.g. trailing spaces after the last value).
+	s = strings.TrimLeft(s, " \t\n\r\v\f")
 	for len(s) > 0 {
 		var key, val string
 		eqIdx := strings.IndexRune(s, '=')
@@ -655,11 +658,9 @@ func parseKeywordValueSettings(s string) (map[string]string, error) {
 				}
 			}
 			val = strings.Replace(strings.Replace(s[:end], "\\\\", "\\", -1), "\\'", "'", -1)
-			if end == len(s) {
-				s = ""
-			} else {
-				s = s[end+1:]
-			}
+			// Consume the value and trim any subsequent whitespace so that
+			// multiple trailing spaces don't cause a spurious parse failure.
+			s = strings.TrimLeft(s[end:], " \t\n\r\v\f")
 		} else { // quoted string
 			s = s[1:]
 			end := 0
@@ -675,11 +676,8 @@ func parseKeywordValueSettings(s string) (map[string]string, error) {
 				return nil, errors.New("unterminated quoted string in connection info string")
 			}
 			val = strings.Replace(strings.Replace(s[:end], "\\\\", "\\", -1), "\\'", "'", -1)
-			if end == len(s) {
-				s = ""
-			} else {
-				s = s[end+1:]
-			}
+			// Consume the closing quote and any subsequent whitespace.
+			s = strings.TrimLeft(s[end+1:], " \t\n\r\v\f")
 		}
 
 		if k, ok := nameMap[key]; ok {

pgconn/config_test.go

@@ -799,6 +799,44 @@ func TestParseConfigKVTrailingBackslash(t *testing.T) {
 	assert.Contains(t, err.Error(), "invalid backslash")
 }
 
+// https://github.com/jackc/pgx/issues/2284
+// Multiple trailing spaces and trailing spaces after quoted values must be
+// accepted as valid keyword/value connection strings.
+func TestParseConfigKVTrailingWhitespace(t *testing.T) {
+	tests := []struct {
+		name       string
+		connString string
+	}{
+		{
+			name:       "single trailing space",
+			connString: "dbname=foo ",
+		},
+		{
+			name:       "multiple trailing spaces",
+			connString: "dbname=foo  ",
+		},
+		{
+			name:       "trailing tab",
+			connString: "dbname=foo\t",
+		},
+		{
+			name:       "quoted value with trailing spaces",
+			connString: "dbname='foo'  ",
+		},
+		{
+			name:       "two key-value pairs with trailing spaces",
+			connString: "port=5432 dbname=foo  ",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := pgconn.ParseConfig(tt.connString)
+			require.NoErrorf(t, err, "conn string %q should not produce an error", tt.connString)
+		})
+	}
+}
+
 func TestConfigCopyReturnsEqualConfig(t *testing.T) {
 	connString := "postgres://jack:secret@localhost:5432/mydb?application_name=pgxtest&search_path=myschema&connect_timeout=5"
 	original, err := pgconn.ParseConfig(connString)