Use PathEscape for dbname in DSN. (#1432)

Support for slashes in database names via url escape codes.
On the other hand, '%' in DSN is now treated as percent-encoding.

Co-authored-by: Brian Hendriks <[email protected]>

Author: methane

Diff for: AUTHORS

@@ -110,6 +110,7 @@ Xuehong Chan <chanxuehong at gmail.com>
 Zhenye Xie <xiezhenye at gmail.com>
 Zhixin Wen <john.wenzhixin at gmail.com>
 Ziheng Lyu <zihenglv at gmail.com>
+Brian Hendriks <brian at dolthub.com>
 
 # Organizations
 
@@ -127,3 +128,4 @@ Percona LLC
 Pivotal Inc.
 Stripe Inc.
 Zendesk Inc.
+Dolthub Inc.

Diff for: README.md

@@ -114,6 +114,12 @@ This has the same effect as an empty DSN string:
 
 ```
 
+`dbname` is escaped by [PathEscape()]()https://pkg.go.dev/net/url#PathEscape) since v1.8.0. If your database name is `dbname/withslash`, it becomes:
+
+```
+/dbname%2Fwithslash
+```
+
 Alternatively, [Config.FormatDSN](https://godoc.org/github.com/go-sql-driver/mysql#Config.FormatDSN) can be used to create a DSN string by filling a struct.
 
 #### Password

Diff for: dsn.go

@@ -203,7 +203,7 @@ func (cfg *Config) FormatDSN() string {
 
 	// /dbname
 	buf.WriteByte('/')
-	buf.WriteString(cfg.DBName)
+	buf.WriteString(url.PathEscape(cfg.DBName))
 
 	// [?param1=value1&...&paramN=valueN]
 	hasParam := false
@@ -365,7 +365,11 @@ func ParseDSN(dsn string) (cfg *Config, err error) {
 					break
 				}
 			}
-			cfg.DBName = dsn[i+1 : j]
+
+			dbname := dsn[i+1 : j]
+			if cfg.DBName, err = url.PathUnescape(dbname); err != nil {
+				return nil, fmt.Errorf("invalid dbname %q: %w", dbname, err)
+			}
 
 			break
 		}

Diff for: dsn_test.go

@@ -50,6 +50,9 @@ var testDSNs = []struct {
 }, {
 	"/dbname",
 	&Config{Net: "tcp", Addr: "127.0.0.1:3306", DBName: "dbname", Collation: "utf8mb4_general_ci", Loc: time.UTC, MaxAllowedPacket: defaultMaxAllowedPacket, Logger: defaultLogger, AllowNativePasswords: true, CheckConnLiveness: true},
+}, {
+	"/dbname%2Fwithslash",
+	&Config{Net: "tcp", Addr: "127.0.0.1:3306", DBName: "dbname/withslash", Collation: "utf8mb4_general_ci", Loc: time.UTC, MaxAllowedPacket: defaultMaxAllowedPacket, Logger: defaultLogger, AllowNativePasswords: true, CheckConnLiveness: true},
 }, {
 	"@/",
 	&Config{Net: "tcp", Addr: "127.0.0.1:3306", Collation: "utf8mb4_general_ci", Loc: time.UTC, MaxAllowedPacket: defaultMaxAllowedPacket, Logger: defaultLogger, AllowNativePasswords: true, CheckConnLiveness: true},
@@ -76,17 +79,20 @@ var testDSNs = []struct {
 
 func TestDSNParser(t *testing.T) {
 	for i, tst := range testDSNs {
-		cfg, err := ParseDSN(tst.in)
-		if err != nil {
-			t.Error(err.Error())
-		}
+		t.Run(tst.in, func(t *testing.T) {
+			cfg, err := ParseDSN(tst.in)
+			if err != nil {
+				t.Error(err.Error())
+				return
+			}
 
-		// pointer not static
-		cfg.TLS = nil
+			// pointer not static
+			cfg.TLS = nil
 
-		if !reflect.DeepEqual(cfg, tst.out) {
-			t.Errorf("%d. ParseDSN(%q) mismatch:\ngot  %+v\nwant %+v", i, tst.in, cfg, tst.out)
-		}
+			if !reflect.DeepEqual(cfg, tst.out) {
+				t.Errorf("%d. ParseDSN(%q) mismatch:\ngot  %+v\nwant %+v", i, tst.in, cfg, tst.out)
+			}
+		})
 	}
 }
 
@@ -113,27 +119,29 @@ func TestDSNParserInvalid(t *testing.T) {
 
 func TestDSNReformat(t *testing.T) {
 	for i, tst := range testDSNs {
-		dsn1 := tst.in
-		cfg1, err := ParseDSN(dsn1)
-		if err != nil {
-			t.Error(err.Error())
-			continue
-		}
-		cfg1.TLS = nil // pointer not static
-		res1 := fmt.Sprintf("%+v", cfg1)
-
-		dsn2 := cfg1.FormatDSN()
-		cfg2, err := ParseDSN(dsn2)
-		if err != nil {
-			t.Error(err.Error())
-			continue
-		}
-		cfg2.TLS = nil // pointer not static
-		res2 := fmt.Sprintf("%+v", cfg2)
+		t.Run(tst.in, func(t *testing.T) {
+			dsn1 := tst.in
+			cfg1, err := ParseDSN(dsn1)
+			if err != nil {
+				t.Error(err.Error())
+				return
+			}
+			cfg1.TLS = nil // pointer not static
+			res1 := fmt.Sprintf("%+v", cfg1)
 
-		if res1 != res2 {
-			t.Errorf("%d. %q does not match %q", i, res2, res1)
-		}
+			dsn2 := cfg1.FormatDSN()
+			cfg2, err := ParseDSN(dsn2)
+			if err != nil {
+				t.Error(err.Error())
+				return
+			}
+			cfg2.TLS = nil // pointer not static
+			res2 := fmt.Sprintf("%+v", cfg2)
+
+			if res1 != res2 {
+				t.Errorf("%d. %q does not match %q", i, res2, res1)
+			}
+		})
 	}
 }