Improve err extraction logic

The previous regexp had superfluous wildcard matching at the beginning
and end. This results in eagerly matching the whole string and
subsequently matches the last occurance of the match.

Instead we don't want to use the wildcard so the default left to right
matching is used and we get the first occurence.

Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>

go/mysql/sqlerror/sql_error.go

@@ -77,7 +77,7 @@ func (se *SQLError) SQLState() string {
 	return se.State
 }
 
-var errExtract = regexp.MustCompile(`.*\(errno ([0-9]*)\) \(sqlstate ([0-9a-zA-Z]{5})\).*`)
+var errExtract = regexp.MustCompile(`\(errno ([0-9]*)\) \(sqlstate ([0-9a-zA-Z]{5})\)`)
 
 // NewSQLErrorFromError returns a *SQLError from the provided error.
 // If it's not the right type, it still tries to get it from a regexp.

go/mysql/sqlerror/sql_error_test.go

@@ -20,10 +20,11 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"vitess.io/vitess/go/vt/proto/vtrpc"
 	"vitess.io/vitess/go/vt/vterrors"
-
-	"github.com/stretchr/testify/assert"
 )
 
 func TestDemuxResourceExhaustedErrors(t *testing.T) {
@@ -173,11 +174,17 @@ func TestNewSQLErrorFromError(t *testing.T) {
 			num: EROutOfResources,
 			ss:  SSUnknownSQLState,
 		},
+		{
+			err: vterrors.Errorf(vtrpc.Code_RESOURCE_EXHAUSTED, "vttablet: rpc error: code = AlreadyExists desc = Duplicate entry '1' for key 'PRIMARY' (errno 1062) (sqlstate 23000) (CallerID: userData1): Sql: \"insert into test(id, `name`) values (:vtg1 /* INT64 */, :vtg2 /* VARCHAR */)\", BindVars: {vtg1: \"type:INT64 value:\\\"1\\\"\"vtg2: \"type:VARCHAR value:\\\"(errno 1366) (sqlstate 10000)\\\"\"}"),
+			num: ERDupEntry,
+			ss:  SSConstraintViolation,
+		},
 	}
 
 	for _, tc := range tCases {
 		t.Run(tc.err.Error(), func(t *testing.T) {
-			err := NewSQLErrorFromError(tc.err).(*SQLError)
+			var err *SQLError
+			require.ErrorAs(t, NewSQLErrorFromError(tc.err), &err)
 			assert.Equal(t, tc.num, err.Number())
 			assert.Equal(t, tc.ss, err.SQLState())
 		})